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  • 1
    Electronic Resource
    Electronic Resource
    Beijerinckia indica var.penicillanicum penicillin V acylase: enhanced enzyme production by catabolite repression-resistant mutant and effect of solvents on enzyme activity (1991)
    Springer
    Journal of industrial microbiology and biotechnology 7 (1991), S. 209-214 
    Details
    ISSN: 1476-5535
    Keywords: Penicillin V acylase ; Beijerinckia indica var.penicillanicum ; Mutation ; Solvent effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Beijerinckia indica var.penicillanicum mutant UREMS-5, producing 168% more penicillin V acylase, was obtained by successive treatment with UV, γ-irradiation and ethylmethane sulfonate. Penicillin V acylase production by the mutant strain was resistant to catabolite repression by glucose. Incorporation of glucose, sodium glutamate and vegetable oils in the medium enhanced enzyme production. The maximum specific production of penicillin V acylase was 244 IU/g dry weight of cells. Effect of solvents on hydrolysis of penicillin V by soluble penicillin V acylase and whole cells was studied. Methylene chloride, chloroform and carbon tetrachloride significantly stimulated the rate of penicillin V hydrolysis by whole cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01575885
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  • 2
    Electronic Resource
    Electronic Resource
    Use of continuous-flow UV-induced mutation technique to enhance chlorinated organic biodegradation (1991)
    Springer
    Journal of industrial microbiology and biotechnology 8 (1991), S. 99-106 
    Details
    ISSN: 1476-5535
    Keywords: Mutation ; UV ; Biodegradation ; Chlorinated organic compound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary In this study, a continuous-flow UV-induced mutation (CUM) device and the CUM device coupled to a selector (CUMS) reactor were fabricated and tested for their ability to enhance the probability of obtaining populations capable of chlorinated organic biodegradation. A mixed culture of bacteria were used as the starting strain for both the CUM and CUMS processes. Populations were obtained from the CUM and CUMS systems capable of 4-chlorobenzoic acid, 2,4-dichlorobenzoic acid and chlorendic acid biodegradation. Non-UV irradiated population served as controls for the experiments and did not demonstrate chlorinated organic biodegradation over the test duration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01578760
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  • 3
    Electronic Resource
    Electronic Resource
    Generation of new functional mutant alleles by premeiotic disruption of the Neurospora crassa am gene (1990)
    Springer
    Current genetics 18 (1990), S. 441-445 
    Details
    ISSN: 1432-0983
    Keywords: Neurospora crassa ; Mutation ; RIP phenomenon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the further analysis of a cross in which the mis-sense allele, am 3, of the Neurospora crassa am (glutamate dehydrogenase) gene was present in one parent together with two ectopic wild-type gene copies, one ascus was identified in which the two ectopic copies had been inactivated by the RIP process whereas the am 3 allele continued to produce its characteristic enzyme variety in active, but heat-sensitive, form. The am 3 allele had also acquired a new HindIII restriction site. It had no detectable methylation. The mutations responsible respectively for the new restriction site and the modified enzyme properties were separated from each other, and from the original am 3 mutation, by selecting for intragenic recombination on either side of the am 3 site. In this way two new effectively wild-type alleles were generated, one characterised by its heat-sensitive and kinetically modified enzyme product and the other by a new HindIII site. These results demonstrate that the RIP phenomenon can be a source of new functional alleles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309914
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  • 4
    Electronic Resource
    Electronic Resource
    Evolutionary consequences of nonrandom damage and repair of chromatin domains (1992)
    Springer
    Journal of molecular evolution 35 (1992), S. 156-180 
    Details
    ISSN: 1432-1432
    Keywords: DNA damage ; DNA repair ; Chromatin ; Evolution ; Nucleosomes ; Nuclear matrix ; Active genes ; Z-DNA ; Sperm ; Mutation ; Molecular clock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Some evolutionary consequences of different rates and trends in DNA damage and repair are explained. Different types of DNA damaging agents cause nonrandom lesions along the DNA. The type of DNA sequence motifs to be preferentially attacked depends upon the chemical or physical nature of the assaulting agent and the DNA base composition. Higher-order chromatin structure, the nonrandom nucleosome positioning along the DNA, the absence of nucleosomes from the promoter regions of active genes, curved DNA, the presence of sequence-specific binding proteins, and the torsional strain on the DNA induced by an increased transcriptional activity all are expected to affect rates of damage of individual genes. Furthermore, potential Z-DNA, H-DNA, slippage, and cruciform structures in the regulatory region of some genes or in other genomic loci induced by torsional strain on the DNA are more prone to modification by genotoxic agents. A specific actively transcribed gene may be preferentially damaged over nontranscribed genes only in specific cell types that maintain this gene in active chromatin fractions because of (1) its decondensed chromatin structure, (2) torsional strain in its DNA, (3) absence of nucleosomes from its regulatory region, and (4) altered nucleosome structure in its coding sequence due to the presence of modified histones and HMG proteins. The situation in this regard of germ cell lineages is, of course, the only one to intervene in evolution. Most lesions in DNA such as those caused by UV or DNA alkylating agents tend to diminish the GC content of genomes. Thus, DNA sequences not bound by selective constraints, such as pseudogenes, will show an increase in their AT content during evolution as evidenced by experimental observations. On the other hand, transcriptionally active parts may be repaired at rates higher than inactive parts of the genome, and proliferating cells may display higher repair activities than quiescent cells. This might arise from a tight coupling of the repair process with both transcription and replication, all these processes taking place on the nuclear matrix. Repair activities differ greatly among species, and there is a good correlation between life span and repair among mammals. It is predicted that genes that are transcriptionally active in germ-cell lineages have a lower mutation rate than bulk DNA, a circumstance that is expected to be reflected in evolution. Exception to this rule might be genes containing potential Z-DNA, H-DNA, or cruciform structures in their coding or regulatory regions that appear to be refractory to repair. This study supports the molecular clock hypothesis when applied to one gene within a group of related species and contends that evolutionary rates might vary between genes and gene segments not only as a result of differences in selective constraints but also as a result of differences in the rate of damage minus rate of repair among different segments of chromatin DNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00183227
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  • 5
    Electronic Resource
    Electronic Resource
    Synonymous substitutions are clustered in enterobacterial genes (1994)
    Springer
    Journal of molecular evolution 39 (1994), S. 448-451 
    Details
    ISSN: 1432-1432
    Keywords: Synonymous substitution ; Escherichia coli ; Salmonella typhimurium ; Mutation ; Recombination ; Selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spatial distribution of synonymous substitutions in enterobacterial genes is investigated. It is shown that synonymous substitutions are significantly clustered in such a way that a synonymous substitution in one codon elevates the rate of synonymous substitution in an adjacent codon by about 10%. The level of clustering does not appear to be related to the level of gene expression, and it is restricted to a range of two or three codons. There are at least three possible explanations: (1) sequence-directed mutagenesis, (2) recombination, and (3) selection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00173413
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  • 6
    Electronic Resource
    Electronic Resource
    Evidence for in vitro induced mutation which improves somatic embryogenesis in Asparagus officinalis L. (1994)
    Springer
    Plant cell reports 13 (1994), S. 372-376 
    Details
    ISSN: 1432-203X
    Keywords: Asparagus officinalis L ; Habituation ; Mutation ; Somatic embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Somatic embryogenesis from different genotypes of Asparagus officinalis L. could be obtained by in vitro culture of shoot apices. Apices were first cultured on an auxin-rich inducing medium and then transferred onto a hormone-free development medium. All genotypes tested in this way produced a few somatic embryos. In some experiments, during the development phase, a new kind of friable highly embryogenic tissue appeared in a random manner. These tissues could be continuously subcultured on a hormone-free medium and were named embryogenic lines. Five of these embryogenic lines regenerated plants from somatic embryos. These regenerated plants exhibited an increased embryogenic response compared to the parent plants; e.g. apex culture produced somatic embryos without any auxin treatments. For one of the embryogenic lines, a genetic analysis showed that the improved embryogenic response of regenerated plants was controlled by a mendelian dominant monogenic mutation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234140
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  • 7
    Electronic Resource
    Electronic Resource
    Energy-dependent mitochondrial mutagenicity of antibacterial ofloxacin and its recombinogenic activity in yeast (1994)
    Springer
    Current genetics 26 (1994), S. 281-284 
    Details
    ISSN: 1432-0983
    Keywords: Ofloxacin ; Mitochondria ; Mutation ; Recombination ; Topoisomerase ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ofloxacin, a specific inhibitor of bacterial topoisomerase II, is known to inhibit the growth of yeast cells and to induce rho − mutants in the yeast S. cerevisiae. The frequency of ofloxacin-induced petite mutants under non-growth conditions was found to be strongly diminished when the cells were depleted in intramitochondrial ATP. Under optimal conditions of mitochondrial mutagenesis the drug induced mitotic recombination and reverse mutation in diploid strains but failed to cure either killer plasmids or the 2 μm DNA of dividing cells. The sensitivity to ofloxacin of the strains deficient in the DNA strandbreak repair pathway (rad52) was significantly higher then that of the wild-type strains and of the mutants deficient in excision or mutagenic DNA repair. The results are compatible with the idea that the cytotoxic and genetic activity of ofloxacin in yeast probably results from the inhibited DNA ligation function of topoisomerase II creating DNA breaks that are reparable through the recombination repair pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00309561
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  • 8
    Electronic Resource
    Electronic Resource
    Diploid yeast cells yield homozygous spontaneous mutations (1993)
    Springer
    Current genetics 23 (1993), S. 430-434 
    Details
    ISSN: 1432-0983
    Keywords: S. cerevisiae ; Mutational homozygosis ; Loss of heterozygosity ; Mutation ; Recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A leucine-requiring hybrid of Saccharomyces cerevisiae, homoallelic at the LEU1 locus (leu1–12/leu1–12) and heterozygous for three chromosome-VII genetic markers distal to the LEU1 locus, was employed to inquire: (1) whether spontaneous gene mutation and mitotic segregation of heterozygous markers occur in positive nonrandom association and (2) whether homozygous LEU1/LEU1 mutant diploids are generated. The results demonstrate that gene mutation of leu1–12 to LEU1 and mitotic segregation of heterozygous chromosome-VII markers occur in strong positive nonrandom association, suggesting that the stimulatory DNA lesion is both mutagenic and recombinogenic. In addition, genetic analysis of diploid Leu+ revertants revealed that approximately 3% of mutations of leu1–12 to LEU1 result in LEU1/LEU1 homozygotes. Red-white sectored Leu+ colonies exhibit genotypes that implicate postreplicational chromatid breakage and exchange near the site of leu1–12 reversion, chromosome loss, and subsequent restitution of diploidy, in the sequence of events leading to mutational homozygosis. By analogy, diploid cell populations can yield variants homozygous for novel recessive gene mutations at biologically significant rates. Mutational homozygosis may be relevant to both carcinogenesis and the evolution of asexual diploid organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312630
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  • 9
    Electronic Resource
    Electronic Resource
    Isolation and characterization of an ω3-desaturation-defective mutant of an arachidonic acid-producing fungus, Mortierella alpina 1S-4 (1994)
    Springer
    Archives of microbiology 161 (1994), S. 316-319 
    Details
    ISSN: 1432-072X
    Keywords: Fatty acids ; Mortierella alpina ; ω3-Desaturation ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A mutant considered to be defective in the conversion of n-6 to n-3 fatty acids (ω3-desaturation) was derived from a Δ5-desaturation-defective mutant (Mut44) of Mortierella alpina 1S-4, after treating its spores with N-methyl-N′-nitro-N-nitrosoguanidine. This mutant cannot produce 8(Z),11(Z),14(Z),17(Z)-eicosatetraenoic acid or any other n-3 fatty acids, of which about 10% was found in its parental strain upon cultivation at 12°C. The mutant's growth rate was comparable to that of the parental strain when grown at 28°C, but it became much slower when the mutant grew at 12°C, at which the lag phase for Mut44 was about 2 d but 5 d for the mutant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303586
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  • 10
    Electronic Resource
    Electronic Resource
    Prolonged environmental stress via a two step process selects mutants of Escherichia, Salmonella and Pseudomonas that grow at 54°C (1991)
    Springer
    Archives of microbiology 156 (1991), S. 307-311 
    Details
    ISSN: 1432-072X
    Keywords: Temperature ; Mutation ; Thermotolerance ; Escherichia coli ; Salmonella typhimurium ; Pseudomonas aeruginosoa ; DNA gyrase ; gyrA ; Nalidixic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A prolonged incubation of Escherichia, Salmonella or Pseudomonas at 48°C with nalidixic acid selected mutants (T48) able to grow at 48°C. A prolonged incubation at 54°C of the T48 mutants selected mutants (T54) able to grow at 54°C. These mutants were susceptible to the same bacteriophages as the original mesophilic strains. Auxotrophic phenotypes of Escherichia coli and Salmonella typhimurium mesophilic parents were demonstrated by these mutants if they were cultivated on minimal agar with cellobiose at 48°C or 54°C or on a minimal agar with glucose at 37°C. The T48 alleles mapped in the gyrA region of E. coli or S. typhimurium chromosome. In S. typhimurium the T54 alleles, which permit growth at 54°C, were shown by cotransductional analysis to be linked to gyrA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00263003
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  • 11
    Electronic Resource
    Electronic Resource
    Induction of SOS like responses by nitrofurantoin in Vibrio cholerae el tor cells (1993)
    Springer
    Archives of microbiology 159 (1993), S. 98-100 
    Details
    ISSN: 1432-072X
    Keywords: Prophage induction ; Weigle reactivation ; Mutation ; Filamentation ; Nitrofurantoin ; Vibrio cholerae el tor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Treatment of Vibrio cholerae el tor strain SLH22(J) with nitrofurantoin induced dose-dependent prophage ‘kappa’, the maximum induction being 6-fold the spontaneous induction level. UV-inactivated ‘kappa’ phages were Weigle reactivated, the maximum Weigle factor being 1.8 and 2.0 respectively in nitrofurantoin and UV pretreated el tor strain H218 Smr. Nitrofurantoin treatment also caused significant filamentation of the el tor strain H218 Smr and mutation of these cells from ampicillin sensitivity to ampicillin resistance. The levels of the four SOS-like responses induced by this drug were low but significant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00244270
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  • 12
    Electronic Resource
    Electronic Resource
    Immune networks modeled by replicator equations (1994)
    Springer
    Journal of mathematical biology 33 (1994), S. 111-137 
    Details
    ISSN: 1432-1416
    Keywords: B-cells ; Immune system ; Idiotypic networks ; Mutation ; Replicator equations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract In order to evaluate the role of idiotypic networks in the operation of the immune system a number of mathematical models have been formulated. Here we examine a class of B-cell models in which cell proliferation is governed by a non-negative, unimodal, symmetric response function f(h), where the field h summarizes the effect of the network on a single clone. We show that by transforming into relative concentrations, the B-cell network equations can be brought into a form that closely resembles the replicator equation. We then show that when the total number of clones in a network is conserved, the dynamics of the network can be represented by the dynamics of a replicator equation. The number of equilibria and their stability are then characterized using methods developed for the study of second-order replicator equations. Analogies with standard Lotka-Volterra equations are also indicated. A particularly interesting result of our analysis is the fact that even though the immune network equations are not second-order, the number and stability of their equilibria can be obtained by a superposition of second-order replicator systems. As a consequence, the problem of finding all of the equilibrium points of the nonlinear network equations can be reduced to solving linear equations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160176
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  • 13
    Electronic Resource
    Electronic Resource
    Mutation in autocatalytic reaction networks (1992)
    Springer
    Journal of mathematical biology 30 (1992), S. 597-632 
    Details
    ISSN: 1432-1416
    Keywords: Autocatalysis ; Mutation ; Perturbation theory ; Qualitative analysis ; Replication dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A class of kinetic equations describing catalysed and template induced replication, and mutation is introduced. This ODE in its most general form is split into two vector fields, a replication and a mutation field. The mutation field is considered as a perturbation of the replicator equation. The perturbation expansion is a Taylor series in a mutation parameter λ. First, second and higher order contributions are computed by means of the conventional Rayleigh-Schrödinger approach. Qualitative shifts in the positions of rest points and limit cycles on the boundary of the physically meaningful part of concentration space are predicted from flow topologies. The results of the topological analysis are summarized in two theorems which turned out to be useful in applications: the rest point migration theorem (RPM) and the limit cycle migration theorem (LCM). Quantitative expressions for the shifts of rest points are computed directly from the perturbation expansion. The concept is applied to a collection of selected examples from biophysical chemistry and biology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175609
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  • 14
    Electronic Resource
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    Inhibition of Mg2+ current by single-gene mutation in Paramecium (1994)
    Springer
    The journal of membrane biology 139 (1994), S. 203-212 
    Details
    ISSN: 1432-1424
    Keywords: Mg2+ current ; Mutation ; Paramecium ; Intracellular Mg2+ homeostasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract “Eccentric” is a newly-isolated mutant of Paramecium tetraurelia that fails to swim backwards in response to Mg2+. In the wild type, this backward swimming results from Mg2+ influx via a Mg2+-specific ion conductance (I Mg. Voltage-clamp analysis confirmed that, as suspected, step changes in membrane potential over a physiological range fail to elicit I Mg from eccentric. Further electrophysiological investigation revealed a number of additional ion-current defects in eccentric: (i) The Ca2+ current activated upon depolarization inactivates more slowly in eccentric than in the wild type, and it requires longer to recover from this inactivation. (ii) The Ca2+-dependent Na+ current deactivates significantly faster in the mutant, (iii) The two K+ currents observed upon hyperpolarization are reduced by 〉60% in eccentric. It is difficult to envision how these varied pleiotropic effects could result from loss of a single ion current. Rather, they suggest that the eccentric mutation affects a global regulatory system. Two plausible hypotheses are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232624
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  • 15
    Electronic Resource
    Electronic Resource
    Mutation in autocatalytic reaction networks (1992)
    Springer
    Journal of mathematical biology 30 (1992), S. 597-631 
    Details
    ISSN: 1432-1416
    Keywords: Autocatalysis ; Mutation ; Perturbation theory ; Qualitative analysis ; Replication dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A class of kinetic equations describing catalysed and template induced replication, and mutation is introduced. This ODE in its most general form is split into two vector fields, a replication and a mutation field. The mutation field is considered as a perturbation of the replicator equation. The perturbation expansion is a Taylor series in a mutation parameter λ. First, second and higher order contributions are computed by means of the conventional Rayleigh-Schrödinger approach. Qualitative shifts in the positions of rest points and limit cycles on the boundary of the physically meaningful part of concentration space are predicted from flow topologies. The results of the topological analysis are summarized in two theorems which turned out to be useful in applications: the rest point migration theorem (RPM) and the limit cycle migration theorem (LCM). Quantitative expressions for the shifts of rest points are computed directly from the perturbation expansion. The concept is applied to a collection of selected examples from biophysical chemistry and biology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00948894
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  • 16
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    The genealogical process of neutral genes with mutation in geographically structured populations (1993)
    Springer
    Journal of mathematical biology 31 (1993), S. 123-132 
    Details
    ISSN: 1432-1416
    Keywords: Genealogy ; Coalescent ; Mutation ; Migration ; Markov chain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract The genealogical process of neutral genes with mutation in geographically structured populations is investigated. Following Watterson [24], the sampled genes are partitioned into two types, old equivalence classes and new equivalence classes. The model is described by a bivariate continuous time Markov chain as an interactive particle system. Some results are obtained in the two-population model and the stepping stone model with symmetric nearest-neighbour migration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00171221
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  • 17
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    What is the difference between models of error thresholds and Muller's ratchet? (1993)
    Springer
    Journal of mathematical biology 32 (1993), S. 33-44 
    Details
    ISSN: 1432-1416
    Keywords: Mutation ; Selection ; Random drift ; Muller's ratchet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract Two independently derived theories predict upper limits to the mutation rate beyond which evolution cannot be controlled by natural selection. One is the theory of Muller's ratchet, explaining the low phylogenetic age of parthenogenetic clones, the other one is the theory of error thresholds, predicting the maximal information content of selfreplicating molecules in prebiotic evolution. Both theories are based on similiar mathematical models but reach qualitatively different conclusions. Muller's ratchet only works in finite populations, while error thresholds are a deterministic phenomenon. In this paper it is shown that this discrepancy is due to different assumptions about the fitness values the selfreplicative units are allowed to assume. If no lower limit for the fitness values is assumed then the deterministic equilibrium frequency of the currently best genotype is strictly positive, no matter how strong mutation is, and random drift is required to cause its extinction (Muller's ratchet). On the other hand, positive lower limits for the fitness values lead to zero equilibrium frequencies in the deterministic description provided the mutation rate is high enough and no back mutations occur.
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    URL: http://dx.doi.org/10.1007/BF00160372
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  • 18
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    Mutation load and mutation-selection-balance in quantitative genetic traits (1994)
    Springer
    Journal of mathematical biology 32 (1994), S. 193-218 
    Details
    ISSN: 1432-1416
    Keywords: Selection ; Mutation ; Mutation load ; Quantitative genetic traits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract Haldane (1937) showed that the reduction of equilibrium mean fitness in an infinite population due to recurrent deleterious mutations depends only on the mutation rate but not on the harmfulness of mutants. His analysis, as well as more recent ones (cf. Crow 1970), ignored back mutation. The purpose of the present paper is to extend these results to arbitrary mutation patterns among alleles and to quantitative genetic traits. We derive first-order approximations for the equilibrium mean fitness (and the mutation load) and determine the order of the error term. For a metric trait under mutation-stabilizing-selection balance our result differs qualitatively from that of Crow and Kimura (1964), whose analysis is based on a Gaussian assumption. Our general approach also yields a mathematical proof that the variance under the usual mutation-stabilizing-selection model is, to first order, µ/s (the house-of-cards approximation) as µ/s tends to zero. This holds for arbitrary mutant distributions and does not require that the population mean coincide with the optimum. We show how the mutant distribution determines the order of the error term, and thus the accuracy of the house-of-cards approximation. Upper and lower bounds to the equilibrium variance are derived that deviate only to second order as µ/s tends to zero. The multilocus case is treated under the assumption of global linkage equilibrium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00163878
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  • 19
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    Moments, cumulants, and polygenic dynamics (1991)
    Springer
    Journal of mathematical biology 30 (1991), S. 199-213 
    Details
    ISSN: 1432-1416
    Keywords: Polygenic dynamics ; Quantitative trait ; Selection ; Mutation ; Cumulants ; Generating function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A new approach for describing the evolution of polygenic traits subject to selection and mutation is presented. Differential equations for the change of cumulants of the allelic frequency distribution at a particular locus and for the cumulants of the distributions of genotypic and phenotypic values are derived. The derivation is based on the assumptions of random mating, no sex differences, absence of random drift, additive gene action, linkage equilibrium, and Hardy-Weinberg proportions. Cumulants are a set of parameters that, like moments, describe the shape of a probability density. Compared with moments, however, they have properties that make them a much more convenient tool for investigating polygenic traits. Applications to directional and stabilizing selection are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160336
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  • 20
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    The generation of Mutator transposable element subfamilies in maize (1994)
    Springer
    Theoretical and applied genetics 87 (1994), S. 657-667 
    Details
    ISSN: 1432-2242
    Keywords: Transposable elements ; Mutation ; Evolution ; DNA repair ; Gene conversion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mobile DNAs of the Mutator system of maize (Zea mays) are exceptional both in structure and diversity. So far, six subfamilies of Mu elements have been discovered; all Mu elements share highly conserved terminal inverted repeats (TIRs), but each sub-family is defined by internal sequences that are apparently unrelated to the internal sequences of any other Mu subfamily. The Mu1/Mu2 subfamily of elements was created by the acquisition of a portion of a standard maize gene (termed MRS-A) within two Mu TIRs. Beside the unusually long (185–359 bp) and diverse TIRs found on all of these elements, other direct and inverted repeats are often found either within the central portion of a Mu element or within a TIR. Our computer analyses have shown that sequence duplications (mostly short direct repeats interrupted by a few base pairs) are common in non-autonomous members of the Mutator, Ac/Ds, and Spm(En) systems. These duplications are often tightly associated with the element-internal end of the TIRs. Comparisons of Mu element sequences have indicated that they share more terminal components than previously reported; all subfamilies have at least the most terminal 215 bp, at one end or the other, of the 359-bp Mu5 TIR. These data suggest that many Mu element subfamilies were generated from a parental element that had termini like those of Mu5. With the Mu5 TIRs as a standard, it was possible to determine that elements like Mu4 could have had their unusual TIRs created through a three-step process involving (1) addition of sequences to interrupt one TIR, (2) formation of a stem-loop structure by one strand of the element, and (3) a subsequent DNA repair/gene conversion event that duplicated the insertion(s) within the other TIR. A similar repair/conversion extending from a TIR stem into loop DNA could explain the additional inverted repeat sequences added to the internal ends of the Mu4 and Mu7 TIRs. This same basic mechanism was found to be capable of generating new Mu element subfamilies. After endonucleolytic attack of the loop within the stem-loop structure, repair/conversion of the gap could occur as an intermolecular event to generate novel internal sequences and, therefore, a new Mu element subfamily. Evidence supporting and expanding this model of new Mu element subfamily creation was identified in the sequence of MRS-A.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222890
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  • 21
    Electronic Resource
    Electronic Resource
    Rapid conversion of rDNA intergenic spacer of diploid mutants of rice derived from γ-ray irradiated tetraploids (1994)
    Springer
    Molecular genetics and genomics 243 (1994), S. 166-172 
    Details
    ISSN: 1617-4623
    Keywords: Rice ; Tetraploid irradiation ; Genome rearrangement ; rDNA ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The organization of tandemly repeated sequences of ribosomal DNA (rDNA) in rice mutants derived from γ-irradiated tetraploids was analyzed. Southern hybridization analysis of nuclear DNA revealed that most of the intergenic spacers (IGSs) in mutant rDNA are replaced concertedly by new molecular species. The new IGSs are produced by the amplification of a subrepeat of about 250 bp. Results obtained from sequence analyses indicate that various intermediate molecular species of the subrepeat were formed during structuring of the IGS region and that many rearrangements occurred between them. These findings demonstrate the effectiveness of recurrent irradiation of tetraploids for inducing artificial genome rearrangement, and also indicate the extreme plasticity and variability of genome structure in plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280313
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  • 22
    Electronic Resource
    Electronic Resource
    Comparison of the nucleotide sequences of the meta-cleavage pathway genes of TOL plasmid pWW0 from Pseudomonas putida with other meta-cleavage genes suggests that both single and multiple nucleotide substitutions contribute to enzyme evolution (1993)
    Springer
    Molecular genetics and genomics 239 (1993), S. 81-89 
    Details
    ISSN: 1617-4623
    Keywords: TOL plasmid ; Biodegradation ; Pseudornonas putida ; Evolution ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract TOL plasmid pWW0 from Pseudomonas putida mt-2 encodes catabolic enzymes required for the oxidation of toluene and xylenes. The structural genes for these catabolic enzymes are clustered into two operons, the xylCMABN operon, which encodes a set of enzymes required for the transformation of toluene/xylenes to benzoate/toluates, and the xylXYZLTEGFJQKIH operon, which encodes a set of enzymes required for the transformation of benzoate/toluates to Krebs cycle intermediates. The latter operon can be divided physically and functionally into two parts, the xylXYZL cluster, which is involved in the transformation of benzoate/toluates to (methyl)catechols, and the xylTEGFJQKIH cluster, which is involved in the transformation of (methyl)catechols to Krebs cycle intermediates. Genes isofunctional to xylXYZL are present in Acinetobacter calcoaceticus, and constitute a benzoate-degradative pathway, while xylTEGFJQKIH homologous encoding enzymes of a methylphenol-degradative pathway and a naphthalene-degradative pathway are present on plasmid pVI150 from P. putida CF600, and on plasmid NAH7 from P. putida PpG7, respectively. Comparison of the nucleotide sequences of the xylXYZLTEGFJQKIH genes with other isofunctional genes suggested that the xylTEGFJQKIH genes on the TOL plasmid diverged from these homologues 20 to 50 million years ago, while the xylXYZL genes diverged from the A. calcoaceticus homologues 100 to 200 million years ago. In codons where amino acids are not conserved, the substitution rate in the third base was higher than that in synonymous codons. This result was interpreted as indicating that both single and multiple nucleotide substitutions contributed to the amino acid-substituting mutations, and hence to enzyme evolution. This observation seems to be general because mammalian globin genes exhibit the same tendency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00281605
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  • 23
    Electronic Resource
    Electronic Resource
    Molecular biology of AMP deaminase deficiency (1994)
    Springer
    Pharmacy world & science 16 (1994), S. 55-61 
    Details
    ISSN: 1573-739X
    Keywords: AMP deaminase/deliciency ; Deficiency diseases ; Genetics, biochemical ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In man, there are at least four isoforms of adenosine monophosphate deaminase (AMPD): myoadenylate deaminase in skeletal muscle, the L isoform in liver, and the E1 and E2 isoforms in erythrocytes. Myoadenylafe deaminase is encoded by the AMPD1 gene located on chromosome 1 p13-p21, the L isoform by the AMPD2 gene, and both isoforms in erythrocytes by the AMPD3 gene. Myoadenylate deaminase deficiency is found in 2–3% of all muscle biopsies. The inborn type of myoadenylate deaminase deficiency is caused by a single mutant allele harbouring two mutations: C34→T (Gin→Stop) and C143→T (Pro-48→Leu). Population studies revealed a frequency of the mutant allele of 0.12 in Caucasian Americans and Germans. The C34→T mutation is located in exon 2, which is alternatively spliced in part of the AMPD1 transcript in human muscle. Since the second mutation does not affect enzyme function, alternatively spliced mRNA encodes a catalytically active enzyme. Only one patient with a disorder linked to liver AMPD has been described so far. In this patient the decreased inhibition of this enzyme by GTP resulted in uric acid overproduction and gout. A complete lack of erythrocyte AMPD activity is found in asymptomatic subjects. The molecular basis of both disorders is not yet known.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01880656
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  • 24
    Electronic Resource
    Electronic Resource
    DNA sequence of the Doe retroposon in the white-one mutant of Drosophila melanogaster and of secondary insertions in the phenotypically altered derivatives white honey and white-eosin (1991)
    Springer
    Molecular genetics and genomics 225 (1991), S. 17-24 
    Details
    ISSN: 1617-4623
    Keywords: Retroposon ; Transposable element ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We analysed the structure of the white locus of Drosophila melanogaster in a family of related white mutants. The white-one mutant has bleach white eyes, and a Doc transposable element is inserted into the promoter region of the white locus. The DNA sequence of this Doc insertion was determined, and showed it to be closely related to other Drosophila melanogaster retroposons such as the I factor and the F, G and jockey elements. There are two long open reading frames, which encode a putative nucleic acid binding protein and a putative reverse transcriptase, respectively. Two independent, partially pigmented derivatives were analysed by cloning sequences from this region. In white-honey a transposable element of the retroviral class, B104, is inserted within the Doe element. In white-eosin there is an insertion within the Doc element of a 190 by sequence that appears to be a member of a novel family of transposable elements. This pogo element is of the same structural class as the Drosophila melanogaster P and hobo elements. These data are consistent with the hypothesis that the Doc retroposon cannot excise, and that, for the white-one mutation, flies with altered phenotypes are most often generated by the insertion of additional transposable elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00282637
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  • 25
    Electronic Resource
    Electronic Resource
    Gene sequence of recA + and construction of recA mutants of Vibrio cholerae (1994)
    Springer
    Molecular genetics and genomics 244 (1994), S. 295-302 
    Details
    ISSN: 1617-4623
    Keywords: DNA repair ; Recombination ; Virulence ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The recA + gene of Vibrio cholerae O1 has been cloned, its nucleotide sequence determined and the product characterized. A deletion mutation was constructed in the recA gene and mutants showed the typical sensitivity to UV and to DNA-damaging agents, as well as an inability to mediate homologous DNA recombination. The chromosomal recA deletion mutants in V. cholerae do not show altered virulence in the infant mouse cholera model and are thus ideal strains for use in complementation studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285457
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  • 26
    Electronic Resource
    Electronic Resource
    Genetic variability of the emm-related genes of the large vir regulon of group A streptococci: potential intra- and intergenomic recombination events (1994)
    Springer
    Molecular genetics and genomics 243 (1994), S. 691-698 
    Details
    ISSN: 1617-4623
    Keywords: Streptococcus pyogenes ; vir regulon ; emm-related genes ; Recombination ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract One of the most prevalent genetic lineages of group A streptococci (GAS) harbors a genomic locus termed the large vir regulon, which contains an emm gene encoding the antiphagocytic M protein, and structurally related fcrA and enn (emm-related) genes encoding immunoglobulin-binding proteins. In the present study more than 100 large vir regulons from 42 different GAS serotypes were analyzed by PCR and partial DNA sequencing. On comparing these data to published sequences, sites of mutational and putative recombinational events were identified and ordered with respect to their intra/intergenic or intra/intergenomic nature. The emm-related genes were found to display small intragenic deletions or insertions, were completely deleted from, or newly inserted into the genome, or were fused to adjacent genes. Intergenomic exchanges of complete emm-related genes, or segments thereof, between different vir regulons were detected. Most of these processes seem to involve short flanking direct repeats. Occasionally, the structural changes could be correlated with changes in the functions of the encoded proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00279579
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  • 27
    Electronic Resource
    Electronic Resource
    Mapping a mutator, mu2, which increases the frequency of terminal deletions in Drosophila melanogaster (1994)
    Springer
    Molecular genetics and genomics 245 (1994), S. 598-607 
    Details
    ISSN: 1617-4623
    Keywords: Deficiency mapping ; Mutation ; Telomere Chromosome structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A mutator, mu2, in Drosophila melanogaster has been identified recently that potentiates the recovery of terminal deficiencies. The deleted chromosomes behave as if they had been capped; that is, they are protected from degradation and from fusion with other chromosome fragments. The mutator maps near the telomere on the left arm of chromosome 3. Using the selectable marker Aprt, 150 deficiencies for region 62 of the cytological map have been recovered. These deficiencies identify the map position of mu2 as 62B11-C1. A yeast artificial chromosome spanning this region has been subcloned into lambda phage, and the positions of deficiency breakpoints on either side of the mu2 gene have been identified within the subclones. These positions limit the location of the left end of the gene to a 23 kb region. In the course of these experiments, three additional, presumptive mutant alleles were identified, suggesting that other mutator alleles remain undiscovered in many standard laboratory stocks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00282222
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  • 28
    Electronic Resource
    Electronic Resource
    nir1, a conditional-lethal mutation in barley causing a defect in nitrite reduction (1993)
    Springer
    Molecular genetics and genomics 236 (1993), S. 275-282 
    Details
    ISSN: 1617-4623
    Keywords: Hordeum vulgare L. ; Nitrite reduction ; Mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eleven green individuals were isolated when 95000 M2 plants of barley (Hordeum vulgare L.), mutagenised with azide in the M1, were screened for nitrite accumulation in their leaves after nitrate treatment in the light. The selected plants were maintained in aerated liquid culture solution containing glutamine as sole nitrogen source. Not all plants survived to flowering and some others that did were not fertile. One of the selected plants, STA3999, from the cultivar Tweed could be crossed to the wild-type cultivar and analysis of the F2 progeny showed that leaf nitrite accumulation was due to a recessive mutation in a single nuclear gene, which has been designated Nir1. The homozygous nir1 mutant could be maintained to flowering in liquid culture with either glutamine or ammonium as sole nitrogen source, but died within 14 days after transfer to compost. The nitrite reductase cross-reacting material seen in nitrate-treated wild-type plants could not be detected in either the leaf or the root of the homozygous nir1 mutant. Nitrite reductase activity, measured with dithionite-reduced methyl viologen as electron donor, of the nitrate-treated homozygous nir1 mutant was much reduced but NADH-nitrate reductase activity was elevated compared to wild-type plants. We conclude that the Nir1 locus determines the formation of nitrite reductase apoprotein in both the leaf and root of barley and speculate that it represents either the nitrite reductase apoprotein gene locus or, less likely, a regulatory locus whose product is required for the synthesis of nitrite reductase, but not nitrate reductase. Elevation of NADH-nitrate reductase activity in the nir1 mutant suggests a regulatory perturbation in the expression of the Narl gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00277123
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  • 29
    Electronic Resource
    Electronic Resource
    Human male infertility may be due to a decrease of the protamine P2 content in sperm chromatin (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 34 (1993), S. 53-57 
    Details
    ISSN: 1040-452X
    Keywords: Spermatozoa ; Gene expression ; Mutation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Basic chromosomal proteins were extracted from the sperm of fertile and infertile human males. The relative proportions of protamine 1, 2, and 3 were determined by scanning microdensitometry following electrophoresis of total protamine in polyacrilamide gels. The findings were as follows: (1) The proportion of protamine P(2 + 3) in sperm obtained from infertile males was lower than that in fertile males. (2) Protamine P(2 + 3) in infertile human males showed reduced affinity to DNA. The possibility that some cases of human male infertility may be due to mutation within the protamine P2 gene is discussed. © 1993 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080340109
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  • 30
    Electronic Resource
    Electronic Resource
    drop out: A third chromosome maternal-effect locus required for formation of the Drosophila cellular blastoderm (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 32 (1992), S. 331-338 
    Details
    ISSN: 1040-452X
    Keywords: Cellularization ; Embryogenesis ; Mutation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: drop out (dop) is a recessive maternal-effect locus identified in a screen for female-sterile mutations in Drosophila polytene region 71C-F. Phenotypic analyses of the dop mutation indicate that the gene is required for proper formation of the cellular blastoderm. In embryos derived from either homozygous or hemizygous dop mothers, cytoplasmic clearing, nuclear migration and division, and pole cell formation appear normal. However, developmental defects are observed prior to and during cellularization of the blastoderm. At the beginning of nuclear cycle 14, the distinct separation of the internal yolk mass and the cortical cytoplasm breaks down. Subsequently, a population of somatic nuclei located at the periphery of the syncytial blastoderm becomes irregularly spaced and nonuniform in their distribution. Despite a somewhat regular formation of the cortical actin network, cellularizaiton in mutant embryos is extremely variable. Such embryos fail to gastrulate normally and produce variable amounts of defective cuticle. Overall, our analyses suggest that the dop gene functions in maintaining the separation of yolk and cortical cytoplasm and in stabilizing the distribution of somatic nuclei in the Drosophila syncytial blastoderm.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080320405
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    Evidence of changes in protease sensitivity and subunit exchange rate on DNA binding by C/EBP (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-08-17
    Description: The transcription factor C/EBP uses a bipartite structural motif to bind DNA. Two protein chains dimerize through a set of amphipathic alpha helices termed the leucine zipper. Highly basic polypeptide regions emerge from the zipper to form a linked set of DNA contact surfaces. In the recently proposed a "scissors grip" model, the paired set of basic regions begin DNA contact at a central point and track in opposite directions along the major groove, forming a molecular clamp around DNA. This model predicts that C/EBP must undertake significant changes in protein conformation as it binds and releases DNA. The basic region of ligand-free C/EBP is highly sensitive to protease digestion. Pronounced resistance to proteolysis occurred when C/EBP associated with its specific DNA substrate. Sequencing of discrete proteolytic fragments showed that prominent sites for proteolysis occur at two junction points predicted by the "scissors grip" model. One junction corresponds to the cleft where the basic regions emerge from the leucine zipper. The other corresponds to a localized nonhelical segment that has been hypothesized to contain an N-cap and facilitate the sharp angulation necessary for the basic region to track continuously in the major groove of DNA.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shuman, J D -- Vinson, C R -- McKnight, S L -- New York, N.Y. -- Science. 1990 Aug 17;249(4970):771-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Research Laboratories, Department of Embryology, Baltimore, MD 21210.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2202050" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; CCAAT-Enhancer-Binding Proteins ; Chromatography, High Pressure Liquid ; DNA/*metabolism ; DNA-Binding Proteins/metabolism ; Kinetics ; Leucine ; Macromolecular Substances ; Models, Molecular ; Molecular Sequence Data ; Nuclear Proteins/*metabolism ; Peptide Fragments/metabolism ; Peptide Hydrolases/*metabolism ; Protein Conformation ; Transcription Factors/*metabolism ; Trypsin/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    GT-1 binding site confers light responsive expression in transgenic tobacco (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-04-27
    Description: Light-dependent expression of rbcS, the gene encoding the small subunit of ribulose-1,5-bisphosphate carboxylase, which is the key enzyme involved in carbon fixation in higher plants, is regulated at the transcriptional level. Sequence analysis of the gene has uncovered a conserved GT motif in the -150 to -100 region of many rbcS promoters. This motif serves as the binding site of a nuclear factor, designated GT-1. Analysis of site-specific mutants of pea rbcS-3A promoter demonstrated that GT-1 binding in vitro is correlated with light-responsive expression of the rbcS promoter in transgenic plants. However, it is not known whether factors other than GT-1 might also be required for activation of transcription by light. A synthetic tetramer of box II (TGTGTGGTTAATATG), the GT-1 binding site located between -152 to -138 of the rbcS-3A promoter, inserted upstream of a truncated cauliflower mosaic virus 35S promoter is sufficient to confer expression in leaves of transgenic tobacco. This expression occurs principally in chloroplast-containing cells, is induced by light, and is correlated with the ability of box II to bind GT-1 in vitro. The data show that the binding site for GT-1 is likely to be a part of the molecular light switch for rbcS activation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lam, E -- Chua, N H -- New York, N.Y. -- Science. 1990 Apr 27;248(4954):471-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Plant Molecular Biology, Rockefeller University, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2330508" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Binding Sites ; Chloramphenicol O-Acetyltransferase/genetics ; Cloning, Molecular ; DNA-Binding Proteins/*metabolism ; Gene Expression Regulation/*physiology ; Genetic Vectors ; *Light ; Molecular Sequence Data ; Mutation ; Nuclear Proteins/*metabolism ; Plant Proteins/*metabolism ; *Plants, Toxic ; Promoter Regions, Genetic/genetics ; Ribulose-Bisphosphate Carboxylase/*genetics ; Tobacco/enzymology/*genetics ; Transcription, Genetic/radiation effects ; Transformation, Genetic
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Common modifications of trimeric G proteins and ras protein: involvement of polyisoprenylation (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-07-13
    Description: The heterotrimeric guanine nucleotide-binding regulatory proteins act at the inner surface of the plasma membrane to relay information from cell surface receptors to effectors inside the cell. These G proteins are not integral membrane proteins, yet are membrane associated. The processing and function of the gamma subunit of the yeast G protein involved in mating-pheromone signal transduction was found to be affected by the same mutations that block ras processing. The nature of these mutations implied that the gamma subunit was polyisoprenylated and that this modification was necessary for membrane association and biological activity. A microbial screen was developed for pharmacological agents that inhibit polyisoprenylation and that have potential application in cancer therapy.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Finegold, A A -- Schafer, W R -- Rine, J -- Whiteway, M -- Tamanoi, F -- CA 41996/CA/NCI NIH HHS/ -- GM 07183/GM/NIGMS NIH HHS/ -- GM 35827/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Jul 13;249(4965):165-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, University of Chicago, IL 60637.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1695391" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Cell Membrane/metabolism ; Cloning, Molecular ; Epitopes/genetics ; GTP-Binding Proteins/genetics/*metabolism ; Hemagglutinins, Viral/immunology ; Lovastatin/pharmacology ; Mevalonic Acid/pharmacology ; Molecular Sequence Data ; Mutation ; Oncogene Protein p21(ras)/genetics/*metabolism ; Orthomyxoviridae/immunology ; Protein Processing, Post-Translational ; Saccharomyces cerevisiae/*genetics/metabolism ; Signal Transduction ; Suppression, Genetic
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 34
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    De novo design, expression, and characterization of Felix: a four-helix bundle protein of native-like sequence (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-08-24
    Description: The protein Felix was designed de novo to fold into an antiparallel four-helix bundle of specific topology. Its sequence of 79 amino acid residues is not homologous to any known protein sequence, but is "native-like" in that it is nonrepetitive and contains 19 of the 20 naturally occurring amino acids. Felix has been expressed from a synthetic gene cloned in Escherichia coli, and the protein has been purified to homogeneity. Physical characterization of the purified protein indicates that Felix (i) is monomeric in solution, (ii) is predominantly alpha-helical, (iii) contains a designed intramolecular disulfide bond linking the first and fourth helices, and (iv) buries its single tryptophan in an apolar environment and probably in close proximity with the disulfide bond. These physical properties rule out several alternative structures and indicate that Felix indeed folds into approximately the designed three-dimensional structure.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hecht, M H -- Richardson, J S -- Richardson, D C -- Ogden, R C -- New York, N.Y. -- Science. 1990 Aug 24;249(4971):884-91.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Duke University, Durham, NC 27710.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2392678" target="_blank"〉PubMed〈/a〉
    Keywords: *Amino Acid Sequence ; Base Sequence ; DNA/genetics ; *Models, Chemical ; Models, Molecular ; Molecular Sequence Data ; *Protein Conformation ; Protein Denaturation ; *Proteins ; *Recombinant Proteins
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 35
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    Structure of human serum albumin (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-07-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Carter, D C -- He, X M -- New York, N.Y. -- Science. 1990 Jul 20;249(4966):302-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Space Science Laboratory, NASA Marshall Space Flight Center, Huntsville, AL 35812.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2374930" target="_blank"〉PubMed〈/a〉
    Keywords: Humans ; Models, Molecular ; Protein Conformation ; *Serum Albumin ; X-Ray Diffraction
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 36
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    GTP-GDP exchange proteins (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-05-18
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Levitzki, A -- New York, N.Y. -- Science. 1990 May 18;248(4957):794.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Chemistry, Hebrew University of Jerusalem, Israel.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2188357" target="_blank"〉PubMed〈/a〉
    Keywords: Guanine Nucleotides/*metabolism ; Guanosine Diphosphate/*metabolism ; Guanosine Triphosphate/*metabolism ; Mutation ; Oncogene Protein p21(ras)/genetics/*metabolism ; Proto-Oncogene Proteins/genetics/*metabolism ; Proto-Oncogene Proteins p21(ras) ; Saccharomyces cerevisiae/genetics/metabolism ; Schizosaccharomyces/genetics/metabolism
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    Design of DNA-binding peptides based on the leucine zipper motif (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-08-17
    Description: A class of transcriptional regulator proteins bind to DNA at dyad-symmetric sites through a motif consisting of (i) a "leucine zipper" sequence that associates into noncovalent, parallel, alpha-helical dimers and (ii) a covalently connected basic region necessary for binding DNA. The basic regions are predicted to be disordered in the absence of DNA and to form alpha helices when bound to DNA. These helices bind in the major groove forming multiple hydrogen-bonded and van der Waals contacts with the nucleotide bases. To test this model, two peptides were designed that were identical to natural leucine zipper proteins only at positions hypothesized to be critical for dimerization and DNA recognition. The peptides form dimers that bind specifically to DNA with their basic regions in alpha-helical conformations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉O'Neil, K T -- Hoess, R H -- DeGrado, W F -- New York, N.Y. -- Science. 1990 Aug 17;249(4970):774-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Central Research and Development Department, E.I. du Pont de Nemours & Co., Wilmington, DE 19880-0328.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2389143" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Binding Sites ; Chemistry, Physical ; Circular Dichroism ; Computer Simulation ; DNA/*metabolism ; DNA-Binding Proteins/*metabolism ; Hydrogen Bonding ; *Leucine ; Macromolecular Substances ; Models, Molecular ; Molecular Sequence Data ; Physicochemical Phenomena ; Protein Conformation
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  • 38
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    DNA looping and unlooping by AraC protein (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-10-26
    Description: Expression of the L-arabinose BAD operon in Escherichia coli is regulated by AraC protein which acts both positively in the presence of arabinose to induce transcription and negatively in the absence of arabinose to repress transcription. The repression of the araBAD promoter is mediated by DNA looping between AraC protein bound at two sites near the promoter separated by 210 base pairs, araI and araO2. In vivo and in vitro experiments presented here show that an AraC dimer, with binding to half of araI and to araO2, maintains the repressed state of the operon. The addition of arabinose, which induces the operon, breaks the loop, and shifts the interactions from the distal araO2 site to the previously unoccupied half of the araI site. The conversion between the two states does not require additional binding of AraC protein and appears to be driven largely by properties of the protein rather than being specified by the slightly different DNA sequences of the binding sites. Slight reorientation of the subunits of AraC could specify looping or unlooping by the protein. Such a mechanism could account for regulation of DNA looping in other systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lobell, R B -- Schleif, R F -- GM18277/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Oct 26;250(4980):528-32.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate Department of Biochemistry, Brandeis University, Waltham, MA 02254.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2237403" target="_blank"〉PubMed〈/a〉
    Keywords: AraC Transcription Factor ; Arabinose/genetics/pharmacology ; *Bacterial Proteins ; Binding Sites ; *DNA, Bacterial/genetics/metabolism ; DNA, Superhelical/metabolism ; Escherichia coli/*genetics ; Escherichia coli Proteins ; Fucose/pharmacology ; Gene Expression Regulation, Bacterial/*drug effects ; Guanine/metabolism ; Macromolecular Substances ; Methylation ; Mutation ; Nucleic Acid Conformation/*drug effects ; Operon ; Protein Conformation/drug effects ; Repressor Proteins/metabolism/*pharmacology ; *Transcription Factors
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  • 39
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    An insertion in the human thyrotropin receptor critical for high affinity hormone binding (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-09-21
    Description: Thyrotropin (TSH), luteinizing hormone (LH), and chorionic gonadotropin (CG) are structurally related glycoprotein hormones, which bind to receptors that share a high degree of sequence similarity. However, comparison of the primary amino acid sequences of the TSH and LH-CG receptors reveals two unique insertions of 8 and 50 amino acids in the extracellular domain of the TSH receptor. The functional significance of these insertions were determined by site-directed mutagenesis. Deletion of the 50-amino acid tract (residues 317 to 366) had no effect on TSH binding or on TSH and thyroid-stimulating immunoglobulin (TSI) biological activities. In contrast, either deletion or substitution of the eight-amino acid region (residues 38 to 45) abolished these activities. This eight-amino acid tract near the amino terminus of the TSH receptor appears to be an important site of interaction for both TSH and TSI.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wadsworth, H L -- Chazenbalk, G D -- Nagayama, Y -- Russo, D -- Rapoport, B -- DK-19289/DK/NIDDK NIH HHS/ -- DK-36182/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1990 Sep 21;249(4975):1423-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine, Veterans Administration Medical Center, San Francisco, CA 94121.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2169649" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Binding Sites ; Cell Line ; Chromosome Deletion ; Clone Cells ; Cyclic AMP/metabolism ; Humans ; Molecular Sequence Data ; Mutation ; Oligonucleotide Probes ; Receptors, Thyrotropin/*genetics/metabolism ; Thyrotropin/*metabolism/pharmacology ; Transfection
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  • 40
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    Testing for carcinogens with rodents (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-09-21
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Abelson, P H -- New York, N.Y. -- Science. 1990 Sep 21;249(4975):1357.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2402628" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Carcinogenicity Tests/*methods ; *Carcinogens ; Mutation ; *Rodentia
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  • 41
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    Defective presentation of endogenous antigen by a cell line expressing class I molecules (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-04-20
    Description: Cytotoxic T lymphocytes (CTLs) recognize class I major histocompatibility complex (MHC) molecules associated with antigenic peptides derived from endogenously synthesized proteins. Binding to such peptides is a requirement for class I assembly in the endoplasmic reticulum (ER). A mutant human cell line, T2, assembles and transports to its surface some, but not all, class I MHC molecules. The class I molecules expressed on the surface of T2 do not present peptides derived from cytosolic antigens, although they can present exogenously added peptides to CTL. The transported class I molecules may interact weakly with an unknown retaining factor in the ER such that they can assemble despite the relative shortage of peptides.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hosken, N A -- Bevan, M J -- AI-19335/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1990 Apr 20;248(4953):367-70.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Immunology, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2326647" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigen-Presenting Cells/*immunology ; Antigens/immunology ; Antigens, Viral/immunology ; B-Lymphocytes/immunology ; Capsid/immunology ; Cell Line ; Endoplasmic Reticulum/immunology ; Gene Expression ; H-2 Antigens/genetics/immunology ; HLA Antigens/genetics ; Histocompatibility Antigens Class I/*immunology ; Histocompatibility Antigens Class II/genetics ; Humans ; Mice ; Mutation ; Ovalbumin/immunology ; Peptides/immunology ; T-Lymphocytes, Cytotoxic/immunology ; Transfection ; Tumor Cells, Cultured ; Viral Core Proteins/immunology
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  • 42
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    Sequence requirements for coiled-coils: analysis with lambda repressor-GCN4 leucine zipper fusions (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-12-07
    Description: A genetic system was developed in Escherichia coli to study leucine zippers with the amino-terminal domain of bacteriophage lambda repressor as a reporter for dimerization. This system was used to analyze the importance of the amino acid side chains at eight positions that form the hydrophobic interface of the leucine zipper dimer from the yeast transcriptional activator, GCN4. When single amino acid substitutions were analyzed, most functional variants contained hydrophobic residues at the dimer interface, while most nonfunctional sequence variants contained strongly polar or helix-breaking residues. In multiple randomization experiments, however, many combinations of hydrophobic residues were found to be nonfunctional, and leucines in the heptad repeat were shown to have a special function in leucine zipper dimerization.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hu, J C -- O'Shea, E K -- Kim, P S -- Sauer, R T -- AI15706/AI/NIAID NIH HHS/ -- GM11117/GM/NIGMS NIH HHS/ -- GM44162/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 7;250(4986):1400-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2147779" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacteriophage lambda/*genetics ; DNA-Binding Proteins/*genetics ; Escherichia coli/*genetics ; Fungal Proteins/*genetics ; Genetic Variation ; Leucine Zippers/*genetics ; Models, Molecular ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Phenotype ; Protein Conformation ; *Protein Kinases ; Random Allocation ; Recombinant Fusion Proteins/metabolism ; *Saccharomyces cerevisiae Proteins ; Transcription Factors/*genetics
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  • 43
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    Involvement of the silencer and UAS binding protein RAP1 in regulation of telomere length (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-10-26
    Description: The yeast protein RAP1, initially described as a transcriptional regulator, binds in vitro to sequences found in a number of seemingly unrelated genomic loci. These include the silencers at the transcriptionally repressed mating-type genes, the promoters of many genes important for cell growth, and the poly[(cytosine)1-3 adenine] [poly(C1-3A)] repeats of telomeres. Because RAP1 binds in vitro to the poly(C1-3A) repeats of telomeres, it has been suggested that RAP1 may be involved in telomere function in vivo. In order to test this hypothesis, the telomere tract lengths of yeast strains that contained conditionally lethal (ts) rap1 mutations were analyzed. Several rap1ts alleles reduced telomere length in a temperature-dependent manner. In addition, plasmids that contain small, synthetic telomeres with intact or mutant RAP1 binding sites were tested for their ability to function as substrates for poly(C1-3A) addition in vivo. Mutations in the RAP1 binding sites reduced the efficiency of the addition reaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lustig, A J -- Kurtz, S -- Shore, D -- GM 40094/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Oct 26;250(4980):549-53.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2237406" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Binding Sites ; Chromosomes, Fungal/metabolism/*ultrastructure ; DNA-Binding Proteins/metabolism ; Fungal Proteins/genetics/*metabolism ; *Genes, Fungal ; *Genes, Mating Type, Fungal ; Molecular Sequence Data ; Mutation ; Plasmids ; Poly A/metabolism ; Poly C/metabolism ; Repetitive Sequences, Nucleic Acid ; Saccharomyces cerevisiae/*genetics ; Temperature ; *Transcription Factors ; Transformation, Genetic
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  • 44
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    Structural characterization of a partly folded apomyoglobin intermediate (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-09-28
    Description: To understand why proteins adopt particular three-dimensional structures, it is important to elucidate the hierarchy of interactions that stabilize the native state. Proteins in partly folded states can be used to dissect protein organizational hierarchies. A partly folded apomyoglobin intermediate has now been characterized structurally by trapping slowly exchanging peptide NH protons and analyzing them by two-dimensional 1H-NMR (nuclear magnetic resonance). Protons in the A, G, and H helix regions are protected from exchange, while protons in the B and E helix regions exchange freely. On the basis of these results and the three-dimensional structure of native myoglobin, a structural model is presented for the partly folded intermediate in which a compact subdomain retains structure while the remainder of the protein is essentially unfolded.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hughson, F M -- Wright, P E -- Baldwin, R L -- DK34909/DK/NIDDK NIH HHS/ -- GM19988/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Sep 28;249(4976):1544-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Beckman Center, Stanford University School of Medicine, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2218495" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Apoproteins/chemistry/*metabolism ; Hydrogen-Ion Concentration ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Sequence Data ; Myoglobin/chemistry/*metabolism ; Protein Conformation ; Spectrophotometry, Ultraviolet
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    Regulation of an enzyme by phosphorylation at the active site (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-08-31
    Description: The isocitrate dehydrogenase of Escherichia coli is an example of a ubiquitous class of enzymes that are regulated by covalent modification. In the three-dimensional structure of the enzyme-substrate complex, isocitrate forms a hydrogen bond with Ser113, the site of regulatory phosphorylation. The structures of Asp113 and Glu113 mutants, which mimic the inactivation of the enzyme by phosphorylation, show minimal conformational changes from wild type, as in the phosphorylated enzyme. Calculations based on observed structures suggest that the change in electrostatic potential when a negative charge is introduced either by phosporylation or site-directed mutagenesis is sufficient to inactivate the enzyme. Thus, direct interaction at a ligand binding site is an alternative mechanism to induced conformational changes from an allosteric site in the regulation of protein activity by phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hurley, J H -- Dean, A M -- Sohl, J L -- Koshland, D E Jr -- Stroud, R M -- GM 24485/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 31;249(4972):1012-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2204109" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Escherichia coli/*enzymology/genetics ; Homeostasis ; Isocitrate Dehydrogenase/genetics/*metabolism ; Models, Molecular ; Molecular Sequence Data ; Phosphorylation ; Protein Conformation
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    Structural transitions upon ligand binding in a cooperative dimeric hemoglobin (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-08-03
    Description: Comparison of the 2.4 angstrom resolution crystal structures of dimeric clam hemoglobin in the deoxygenated and carbon-monoxide liganded states shows how radically different the structural basis for cooperative oxygen binding is from that operative in mammalian hemoglobins. Heme groups are in direct communication across a novel subunit interface formed by the E and F helices. The conformational changes at this interface that accompany ligand binding are more dramatic at a tertiary level but more subtle at a quaternary level than those in mammalian hemoglobins. These findings suggest a cooperative mechanism that links ligation at one subunit with potentiation of affinity at the second subunit.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Royer, W E Jr -- Hendrickson, W A -- Chiancone, E -- New York, N.Y. -- Science. 1990 Aug 3;249(4968):518-21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2382132" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Carboxyhemoglobin/metabolism ; Hemoglobins/*metabolism ; Ligands ; Macromolecular Substances ; Models, Molecular ; Molecular Sequence Data ; Mollusca ; Protein Conformation
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  • 47
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    The structure of a complex of recombinant hirudin and human alpha-thrombin (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-07-20
    Description: The crystallographic structure of a recombinant hirudin-thrombin complex has been solved at 2.3 angstrom (A) resolution. Hirudin consists of an NH2-terminal globular domain and a long (39 A) COOH-terminal extended domain. Residues Ile1 to Tyr3 of hirudin form a parallel beta-strand with Ser214 to Glu217 of thrombin with the nitrogen atom of Ile1 making a hydrogen bond with Ser195 O gamma atom of the catalytic site, but the specificity pocket of thrombin is not involved in the interaction. The COOH-terminal segment makes numerous electrostatic interactions with an anion-binding exosite of thrombin, whereas the last five residues are in a helical loop that forms many hydrophobic contacts. In all, 27 of the 65 residues of hirudin have contacts less than 4.0 A with thrombin (10 ion pairs and 23 hydrogen bonds). Such abundant interactions may account for the high affinity and specificity of hirudin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rydel, T J -- Ravichandran, K G -- Tulinsky, A -- Bode, W -- Huber, R -- Roitsch, C -- Fenton, J W 2nd -- HL13160/HL/NHLBI NIH HHS/ -- HL43229/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Jul 20;249(4966):277-80.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Michigan State University, East Lansing 48824.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2374926" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Hirudins/*metabolism ; Humans ; Models, Molecular ; Molecular Sequence Data ; Protein Binding ; Protein Conformation ; Recombinant Proteins/metabolism ; Thrombin/*metabolism ; X-Ray Diffraction
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  • 48
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    Metalloantibodies (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-08-10
    Description: A metalloantibody has been constructed with a coordination site for metals in the antigen binding pocket. The Zn(II) binding site from carbonic anhydrase B was used as a model. Three histidine residues have been placed in the light chain complementarity determining regions of a single chain antibody molecule. In contrast to the native protein, the mutant displayed metal-dependent fluorescence-quenching behavior. This response was interpreted as evidence for metal binding in the three-histidine site with relative affinities in the order Cu(II) greater than Zn(II) greater than Cd(II). The presence of metal cofactors in immunoglobulins should facilitate antibody catalysis of redox and hydrolytic reactions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Iverson, B L -- Iverson, S A -- Roberts, V A -- Getzoff, E D -- Tainer, J A -- Benkovic, S J -- Lerner, R A -- F32GM-1204702/GM/NIGMS NIH HHS/ -- IGM 37684/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 10;249(4969):659-62.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2116666" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; *Binding Sites, Antibody ; Cadmium ; Carbonic Anhydrases/*immunology ; Copper ; Fluoresceins ; Immunoglobulin Heavy Chains ; Immunoglobulin Light Chains ; Ligands ; *Metals ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Spectrometry, Fluorescence ; Zinc
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    Translation initiation and ribosomal biogenesis: involvement of a putative rRNA helicase and RPL46 (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-03-02
    Description: Cold-sensitive mutations in the SPB genes (spb1-spb7) of Saccharomyces cerevisiae suppress the inhibition of translation initiation resulting from deletion of the poly(A)-binding protein gene (PAB1). The SPB4 protein belongs to a family of adenosine triphosphate (ATP)-dependent RNA helicases. The aberrant production of 25S ribosomal RNA (rRNA) occurring in spb4-1 mutants or the deletion of SPB2 (RPL46) permits the deletion of PAB1. These data suggest that mutations affecting different steps of 60S subunit formation can allow PAB-independent translation, and they indicate that further characterization of the spb mutations could lend insight into the biogenesis of the ribosome.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sachs, A B -- Davis, R W -- R37 GM 21891/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Mar 2;247(4946):1077-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Stanford Medical Center, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2408148" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Carrier Proteins/genetics/metabolism ; DEAD-box RNA Helicases ; Molecular Sequence Data ; Mutation ; Poly(A)-Binding Proteins ; *Protein Biosynthesis ; RNA Nucleotidyltransferases/genetics/*metabolism ; RNA Processing, Post-Transcriptional ; RNA, Fungal/genetics/metabolism ; RNA, Ribosomal/genetics/*metabolism ; Ribosomal Proteins/genetics/*metabolism ; Ribosomes/*metabolism ; Saccharomyces cerevisiae/enzymology/*genetics ; *Saccharomyces cerevisiae Proteins ; Sequence Homology, Nucleic Acid
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    T cells responsive to myelin basic protein in patients with multiple sclerosis (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-02-09
    Description: Gene mutation in vivo in human T lymphocytes appears to occur preferentially in dividing cells. Individuals with multiple sclerosis (MS) are assumed to have one or more populations of diving T cells that are being stimulated by autoantigens. Mutant T cell clones from MS patients were isolated and tested for reactivity to myelin basic protein, an antigen that is thought to participate in the induction of the disease. The hypoxanthine guanine phosphoribosyltransferase (hprt) clonal assay was used to determine mutant frequency values in MS patients with chronic progressive disease. Eleven of 258 thioguanine-resistant (hprt-) T cell clones from five of the six MS patients who were tested proliferated in response to human myelin basic protein without prior in vitro exposure to this antigen. No wild-type clones from these patients, nor any hprt- or wild-type clones from three healthy individuals responded to myelin basic protein. Thus, T cell clones that react with myelin basic protein can be isolated from the peripheral blood of MS patients.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Allegretta, M -- Nicklas, J A -- Sriram, S -- Albertini, R J -- CA30688-07/CA/NCI NIH HHS/ -- NS00849/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1990 Feb 9;247(4943):718-21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Genetics Laboratory, University of Vermont, Burlington 05401.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1689076" target="_blank"〉PubMed〈/a〉
    Keywords: Adult ; Autoantigens/immunology ; Cell Division ; Clone Cells/immunology ; Female ; Humans ; Hypoxanthine Phosphoribosyltransferase/genetics ; Male ; Middle Aged ; Multiple Sclerosis/genetics/*immunology ; Mutation ; Myelin Basic Protein/*immunology ; T-Lymphocytes/drug effects/*immunology ; Thioguanine/pharmacology ; X Chromosome
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    A mouse model of the aniridia-Wilms tumor deletion syndrome (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-11-09
    Description: Deletion of chromosome 11p13 in humans produces the WAGR syndrome, consisting of aniridia (an absence or malformation of the iris), Wilms tumor (nephroblastoma), genitourinary malformations, and mental retardation. An interspecies backcross between Mus musculus/domesticus and Mus spretus was made in order to map the homologous chromosomal region in the mouse genome and to define an animal model of this syndrome. Nine evolutionarily conserved DNA clones from proximal human 11p were localized on mouse chromosome 2 near Small-eyes (Sey), a semidominant mutation that is phenotypically similar to aniridia. Analysis of Dickie's Small-eye (SeyDey), a poorly viable allele that has pleiotropic effects, revealed the deletion of three clones, f3, f8, and k13, which encompass the aniridia (AN2) and Wilms tumor susceptibility genes in man. Unlike their human counterparts, SeyDey/+ mice do not develop nephroblastomas. These findings suggest that the Small-eye defect is genetically equivalent to human aniridia, but that loss of the murine homolog of the Wilms tumor gene is not sufficient for tumor initiation. A comparison among Sey alleles suggests that the AN2 gene product is required for induction of the lens and nasal placodes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Glaser, T -- Lane, J -- Housman, D -- 2 T32 GMO7753-11/GM/NIGMS NIH HHS/ -- GM27882/GM/NIGMS NIH HHS/ -- T32 GM007753/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Nov 9;250(4982):823-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2173141" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Aniridia/*genetics ; Blotting, Southern ; Chromosome Deletion ; Chromosome Mapping ; DNA/analysis ; *Disease Models, Animal ; Eye/embryology/pathology ; Female ; Genes, Wilms Tumor/*genetics ; Genetic Markers ; Kidney Neoplasms/*genetics ; Male ; Mice ; Mice, Inbred C3H ; Mice, Inbred C57BL ; Muridae ; Mutation ; Phenotype ; Polymorphism, Genetic ; Syndrome ; Wilms Tumor/*genetics
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    HSP104 required for induced thermotolerance (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-06-01
    Description: A heat shock protein gene, HSP104, was isolated from Saccharomyces cerevisiae and a deletion mutation was introduced into yeast cells. Mutant cells grew at the same rate as wild-type cells and died at the same rate when exposed directly to high temperatures. However, when given a mild pre-heat treatment, the mutant cells did not acquire tolerance to heat, as did wild-type cells. Transformation with the wild-type gene rescued the defect of mutant cells. The results demonstrate that a particular heat shock protein plays a critical role in cell survival at extreme temperatures.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sanchez, Y -- Lindquist, S L -- GM 35483/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Jun 1;248(4959):1112-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2188365" target="_blank"〉PubMed〈/a〉
    Keywords: Cloning, Molecular ; Fungal Proteins/biosynthesis/*genetics ; Genes, Fungal ; Heat-Shock Proteins/biosynthesis/genetics/*physiology ; *Hot Temperature ; Mutation ; Restriction Mapping ; Saccharomyces cerevisiae/genetics/growth & development/*physiology
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    The microchip microbe hunters (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-02-16
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Alper, J -- New York, N.Y. -- Science. 1990 Feb 16;247(4944):804-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2154848" target="_blank"〉PubMed〈/a〉
    Keywords: Acquired Immunodeficiency Syndrome/drug therapy ; *Antiviral Agents/therapeutic use ; Capsid/ultrastructure ; Common Cold/*drug therapy ; Drug Design ; Humans ; Models, Molecular ; Protein Conformation ; Rhinovirus/ultrastructure ; Software
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    Transmembrane protein structure: spin labeling of bacteriorhodopsin mutants (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-06-01
    Description: Transmembrane proteins serve important biological functions, yet precise information on their secondary and tertiary structure is very limited. The boundaries and structures of membrane-embedded domains in integral membrane proteins can be determined by a method based on a combination of site-specific mutagenesis and nitroxide spin labeling. The application to one polypeptide segment in bacteriorhodopsin, a transmembrane chromoprotein that functions as a light-driven proton pump is described. Single cysteine residues were introduced at 18 consecutive positions (residues 125 to 142). Each mutant was reacted with a specific spin label and reconstituted into vesicles that were shown to be functional. The relative collision frequency of each spin label with freely diffusing oxygen and membrane-impermeant chromium oxalate was estimated with power saturation EPR (electron paramagnetic resonance) spectroscopy. The results indicate that residues 129 to 131 form a short water-exposed loop, while residues 132 to 142 are membrane-embedded. The oxygen accessibility for positions 131 to 138 varies with a periodicity of 3.6 residues, thereby providing a striking demonstration of an alpha helix. The orientation of this helical segment with respect to the remainder of the protein was determined.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Altenbach, C -- Marti, T -- Khorana, H G -- Hubbell, W L -- AI 11479/AI/NIAID NIH HHS/ -- EY05216/EY/NEI NIH HHS/ -- GM28289/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Jun 1;248(4959):1088-92.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Jules Stein Eye Institute, University of California, Los Angeles 90024-7008.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2160734" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; *Bacteriorhodopsins/genetics ; Cysteine/genetics ; Electron Spin Resonance Spectroscopy ; *Membrane Proteins/genetics ; Molecular Sequence Data ; Mutation ; Oxalates ; Oxalic Acid ; Oxygen ; Protein Conformation ; Spin Labels
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    Paleoanthropology gets physical (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-02-16
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Marshall, E -- New York, N.Y. -- Science. 1990 Feb 16;247(4944):798-801.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2369435" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Anthropology ; Carbon Radioisotopes ; DNA, Mitochondrial/genetics ; Hominidae/*genetics ; Humans ; Israel ; Mutation ; *Paleontology ; South Africa
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    Ligand-induced transformation by a noninternalizing epidermal growth factor receptor (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-02-23
    Description: Identification of a mutant epidermal growth factor (EGF) receptor that does not undergo downregulation has provided a genetic probe to investigate the role of internalization in ligand-induced mitogenesis. Contact-inhibited cells expressing this internalization-defective receptor exhibited a normal mitogenic response at significantly lower ligand concentrations than did cells expressing wild-type receptors. A transformed phenotype and anchorage-independent growth were observed at ligand concentrations that failed to elicit these responses in cells expressing wild-type receptors. These findings imply that activation of the protein tyrosine kinase activity at the cell membrane is sufficient for the growth-enhancing effects of EGF. Thus, downregulation can serve as an attenuation mechanism, without which transformation ensues.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wells, A -- Welsh, J B -- Lazar, C S -- Wiley, H S -- Gill, G N -- Rosenfeld, M G -- DDK 13149/DK/NIDDK NIH HHS/ -- DDK 18477/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1990 Feb 23;247(4945):962-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, University of California-San Diego, La Jolla 92093.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2305263" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Division ; Cell Line ; Down-Regulation ; *Endocytosis ; Enzyme Activation ; Epidermal Growth Factor/pharmacology ; Genetic Vectors ; Moloney murine leukemia virus/genetics ; Mutation ; Phenotype ; Protein-Tyrosine Kinases/metabolism ; Receptor, Epidermal Growth Factor/genetics/*metabolism ; Transfection
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    Linkage of a cardiac arrhythmia, the long QT syndrome, and the Harvey ras-1 gene (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-05-03
    Description: Genetic factors contribute to heart disease. In this study, linkage analyses have been performed in a family that is predisposed to sudden death from cardiac arrhythmias, the long QT syndrome (LQT). A DNA marker at the Harvey ras-1 locus (H-ras-1) was linked to LQT with a logarithm of the likelihood ratio for linkage (lod score) of 16.44 at theta = 0, which confirms the genetic basis of this trait and localizes this gene to the short arm of chromosome 11. As no recombination was observed between LQT and H-ras-1, and there is a physiological rationale for its involvement in this disease, ras becomes a candidate for the disease locus.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Keating, M -- Atkinson, D -- Dunn, C -- Timothy, K -- Vincent, G M -- Leppert, M -- New York, N.Y. -- Science. 1991 May 3;252(5006):704-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Human Genetics, University of Utah Health Sciences Center, Salt Lake City 84132.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1673802" target="_blank"〉PubMed〈/a〉
    Keywords: Chromosome Mapping ; Chromosomes, Human, Pair 11 ; Electrocardiography ; *Genes, ras ; Humans ; *Lod Score ; Long QT Syndrome/*genetics/physiopathology ; Mutation ; Pedigree ; Polymorphism, Restriction Fragment Length
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    Structure of a peptide inhibitor bound to the catalytic subunit of cyclic adenosine monophosphate-dependent protein kinase (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-07-26
    Description: The structure of a 20-amino acid peptide inhibitor bound to the catalytic subunit of cyclic AMP-dependent protein kinase, and its interactions with the enzyme, are described. The x-ray crystal structure of the complex is the basis of the analysis. The peptide inhibitor, derived from a naturally occurring heat-stable protein kinase inhibitor, contains an amphipathic helix that is followed by a turn and an extended conformation. The extended region occupies the cleft between the two lobes of the enzyme and contains a five-residue consensus recognition sequence common to all substrates and peptide inhibitors of the catalytic subunit. The helical portion of the peptide binds to a hydrophobic groove and conveys high affinity binding. Loops from both domains converge at the active site and contribute to a network of conserved residues at the sites of magnesium adenosine triphosphate binding and catalysis. Amino acids associated with peptide recognition, nonconserved, extend over a large surface area.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Knighton, D R -- Zheng, J H -- Ten Eyck, L F -- Xuong, N H -- Taylor, S S -- Sowadski, J M -- RR01644/RR/NCRR NIH HHS/ -- T32CA09523/CA/NCI NIH HHS/ -- T32DK07233/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1991 Jul 26;253(5018):414-20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, San Diego, La Jolla 92093-0654.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1862343" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Carrier Proteins/*chemistry/metabolism ; Computer Simulation ; Enzyme Inhibitors/*chemistry ; *Intracellular Signaling Peptides and Proteins ; Macromolecular Substances ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Kinases/*chemistry/metabolism ; X-Ray Diffraction
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    A nonconservative serine to cysteine mutation in the sulfate-binding protein, a transport receptor (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-03-22
    Description: Serine 130 is one of seven residues that form a total of seven hydrogen bonds with the sulfate completely sequestered deep in the cleft between the two lobes of the bilobate sulfate-binding protein from Salmonella typhimurium. This residue has been replaced with Cys, Ala, and Gly by site-directed mutagenesis in an Escherichia coli expression system. Replacement with the isosteric Cys caused a 3200-fold decrease in the sulfate-binding activity relative to the wild-type activity, whereas replacement with Ala and Gly resulted in only 100- and 15-fold decreases, respectively. The effect of the Cys substitution is attributed largely to steric effect, whereas the Gly substitution more nearly reflects the loss of one hydrogen bond to the bound sulfate with a strength of only 1.6 kilocalories per mole.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉He, J J -- Quiocho, F A -- New York, N.Y. -- Science. 1991 Mar 22;251(5000):1479-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Baylor College of Medicine, Houston, TX 77030.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1900953" target="_blank"〉PubMed〈/a〉
    Keywords: *Bacterial Proteins ; Binding Sites ; Carrier Proteins/chemistry/*genetics/metabolism ; Cysteine ; DNA Mutational Analysis ; *Escherichia coli Proteins ; Hydrogen Bonding ; Hydrogen-Ion Concentration ; Models, Molecular ; *Periplasmic Binding Proteins ; Salmonella typhimurium ; Serine ; Structure-Activity Relationship ; Sulfates/*chemistry ; Thermodynamics
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    Structural features that give rise to the unusual stability of RNA hairpins containing GNRA loops (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-07-12
    Description: The most frequently occurring RNA hairpins in 16S and 23S ribosomal RNA contain a tetranucleotide loop that has a GNRA consensus sequence. The solution structures of the GCAA and GAAA hairpins have been determined by nuclear magnetic resonance spectroscopy. Both loops contain an unusual G-A base pair between the first and last residue in the loop, a hydrogen bond between a G base and a phosphate, extensive base stacking, and a hydrogen bond between a sugar 2'-end OH and a base. These interactions explain the high stability of these hairpins and the sequence requirements for the variant and invariant nucleotides in the GNRA tetranucleotide loop family.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Heus, H A -- Pardi, A -- AI 27026/AI/NIAID NIH HHS/ -- AI 30726/AI/NIAID NIH HHS/ -- RR03283/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1991 Jul 12;253(5016):191-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1712983" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Computer Graphics ; Hydrogen Bonding ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; Oligoribonucleotides/chemistry ; RNA/chemistry/*ultrastructure ; Structure-Activity Relationship ; Thermodynamics
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    Three-dimensional structures of the ligand-binding domain of the bacterial aspartate receptor with and without a ligand (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-12-09
    Description: The three-dimensional structure of an active, disulfide cross-linked dimer of the ligand-binding domain of the Salmonella typhimurium aspartate receptor and that of an aspartate complex have been determined by x-ray crystallographic methods at 2.4 and 2.0 angstrom (A) resolution, respectively. A single subunit is a four-alpha-helix bundle with two long amino-terminal and carboxyl-terminal helices and two shorter helices that form a cylinder 20 A in diameter and more than 70 A long. The two subunits in the disulfide-bonded dimer are related by a crystallographic twofold axis in the apo structure, but by a noncrystallographic twofold axis in the aspartate complex structure. The latter structure reveals that the ligand binding site is located more than 60 A from the presumed membrane surface and is at the interface of the two subunits. Aspartate binds between two alpha helices from one subunit and one alpha helix from the other in a highly charged pocket formed by three arginines. The comparison of the apo and aspartate complex structures shows only small structural changes in the individual subunits, except for one loop region that is disordered, but the subunits appear to change orientation relative to each other. The structures of the two forms of this protein provide a step toward understanding the mechanisms of transmembrane signaling.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Milburn, M V -- Prive, G G -- Milligan, D L -- Scott, W G -- Yeh, J -- Jancarik, J -- Koshland, D E Jr -- Kim, S H -- AI 30725/AI/NIAID NIH HHS/ -- DK09765/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1991 Nov 29;254(5036):1342-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1660187" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Aspartic Acid/metabolism ; Binding Sites ; Disulfides/analysis ; Hydrogen Bonding ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; *Receptors, Amino Acid ; Receptors, Cell Surface/*chemistry/metabolism ; Salmonella typhimurium/metabolism ; X-Ray Diffraction
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    Crystal structure of defensin HNP-3, an amphiphilic dimer: mechanisms of membrane permeabilization (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-03-22
    Description: Defensins (molecular weight 3500 to 4000) act in the mammalian immune response by permeabilizing the plasma membranes of a broad spectrum of target organisms, including bacteria, fungi, and enveloped viruses. The high-resolution crystal structure of defensin HNP-3 (1.9 angstrom resolution, R factor 0.19) reveals a dimeric beta sheet that has an architecture very different from other lytic peptides. The dimeric assembly suggests mechanisms by which defensins might bind to and permeabilize the lipid bilayer.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hill, C P -- Yee, J -- Selsted, M E -- Eisenberg, D -- New York, N.Y. -- Science. 1991 Mar 22;251(5000):1481-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Eisenberg, Molecular Biology Institute, Los Angeles, CA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2006422" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Blood Proteins/chemistry/*ultrastructure ; Cell Membrane Permeability ; Crystallography ; Defensins ; Guinea Pigs ; Humans ; Macromolecular Substances ; Membrane Proteins/chemistry/ultrastructure ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; Protein Conformation ; Rabbits ; Rats ; Structure-Activity Relationship ; X-Ray Diffraction ; *alpha-Defensins
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    Similarity of protein G and ubiquitin (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-10-25
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kraulis, P J -- New York, N.Y. -- Science. 1991 Oct 25;254(5031):581-2.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1658931" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites, Antibody ; Immunoglobulin G ; Models, Molecular ; Molecular Sequence Data ; Nerve Tissue Proteins/*chemistry/genetics/immunology ; Protein Conformation ; Sequence Homology, Nucleic Acid ; Ubiquitins/*chemistry/genetics
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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    Generation of cAMP-activated chloride currents by expression of CFTR (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-02-08
    Description: Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) cause cystic fibrosis. In order to evaluate its function, CFTR was expressed in HeLa, Chinese hamster ovary (CHO), and NIH 3T3 fibroblast cells, and anion permeability was assessed with a fluorescence microscopic assay and the whole-cell patch-clamp technique. Adenosine 3',5'-monophosphate (cAMP) increased anion permeability and chloride currents in cells expressing CFTR, but not in cells expressing a mutant CFTR (delta F508) or in nontransfected cells. The simplest interpretation of these observations is that CFTR is itself a cAMP-activated chloride channel. The alternative interpretation, that CFTR directly or indirectly regulates chloride channels, requires that these cells have endogenous cryptic, chloride channels that are stimulated by cAMP only in the presence of CFTR.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Anderson, M P -- Rich, D P -- Gregory, R J -- Smith, A E -- Welsh, M J -- New York, N.Y. -- Science. 1991 Feb 8;251(4994):679-82.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1704151" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; Chloride Channels ; Chlorides/*metabolism ; Cricetinae ; Cyclic AMP/*physiology ; Cystic Fibrosis Transmembrane Conductance Regulator ; Humans ; Membrane Proteins/*metabolism/*physiology ; Mice ; Mutation ; Recombinant Proteins ; Structure-Activity Relationship
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    Global suppression of protein folding defects and inclusion body formation (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-07-05
    Description: Amino acid substitutions at a site in the center of the bacteriophage protein P22 tailspike polypeptide chain suppress temperature-sensitive folding mutations at many sites throughout the chain. Characterization of the intracellular folding and chain assembly process reveals that the suppressors act in the folding pathway, inhibiting the aggregation of an early folding intermediate into the kinetically trapped inclusion body state. The suppressors alone increase the folding efficiency of the otherwise wild-type polypeptide chain without altering the stability or activity of the native state. These amino acid substitutions identify an unexpected aspect of the protein folding grammar--sequences within the chain that carry information inhibiting unproductive off-pathway conformations. Such mutations may serve to increase the recovery of protein products of cloned genes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mitraki, A -- Fane, B -- Haase-Pettingell, C -- Sturtevant, J -- King, J -- GMS17,980/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1991 Jul 5;253(5015):54-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1648264" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Coliphages ; DNA Mutational Analysis ; Electrophoresis, Polyacrylamide Gel ; Gene Expression Regulation ; Inclusion Bodies/*chemistry ; Molecular Sequence Data ; Mutation ; *Protein Conformation ; Viral Proteins/*chemistry ; Viral Tail Proteins
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    Triplex DNA finally comes of age (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-06-07
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Moffat, A S -- New York, N.Y. -- Science. 1991 Jun 7;252(5011):1374-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2047850" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; DNA/*chemistry ; DNA Replication ; Genes, myc ; Models, Molecular ; Molecular Sequence Data ; Transcription, Genetic/drug effects
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    Engineered metal-binding proteins: purification to protein folding (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-06-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Arnold, F H -- Haymore, B L -- New York, N.Y. -- Science. 1991 Jun 28;252(5014):1796-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1648261" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Carrier Proteins/*chemical synthesis/chemistry/isolation & purification ; Cytochrome c Group/chemistry ; Histidine ; Ligands ; Metals/*metabolism ; Models, Molecular ; Protein Conformation ; *Protein Engineering
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    Laser ablation studies of the role of the Drosophila oocyte nucleus in pattern formation (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-10-11
    Description: Somatic and germline cells interact during oogenesis to establish the pattern axes of the Drosophila eggshell and embryo. The role of the oocyte nucleus in pattern formation was tested with the use of laser ablation. Ablation in stage 6 to 9 egg chambers caused partial or complete ventralization of the eggshell, phenotypes similar to those of eggs produced by gurken or torpedo females. Accumulation of vasa protein at the posterior pole of treated oocytes was also disrupted. Thus the oocyte nucleus is required as late as stage 9 for dorsoventral patterning within the follicle cells and for polar plasm assembly in the oocyte.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Montell, D J -- Keshishian, H -- Spradling, A C -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 1991 Oct 11;254(5029):290-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Carnegie Institution of Washington, Baltimore, MD 21210.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1925585" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Nucleus/*physiology ; Cell Polarity/physiology ; Drosophila/*embryology ; Egg Shell ; Genes ; Laser Therapy ; Microsurgery ; Morphogenesis ; Mutation ; Oocytes/*physiology ; Oogenesis
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    First protein kinase structure (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-07-26
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hoffman, M -- New York, N.Y. -- Science. 1991 Jul 26;253(5018):383.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1862341" target="_blank"〉PubMed〈/a〉
    Keywords: Carrier Proteins/chemistry/metabolism ; Enzyme Inhibitors/chemistry ; *Intracellular Signaling Peptides and Proteins ; Models, Molecular ; Protein Conformation ; Protein Kinases/*chemistry/metabolism
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    The three-dimensional structure of canine parvovirus and its functional implications (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-03-22
    Description: The three-dimensional atomic structure of a single-stranded DNA virus has been determined. Infectious virions of canine parvovirus contain 60 protein subunits that are predominantly VP-2. The central structural motif of VP-2 has the same topology (an eight-stranded antiparallel beta barrel) as has been found in many other icosahedral viruses but represents only about one-third of the capsid protein. There is a 22 angstrom (A) long protrusion on the threefold axes, a 15 A deep canyon circulating about each of the five cylindrical structures at the fivefold axes, and a 15 A deep depression at the twofold axes. By analogy with rhinoviruses, the canyon may be the site of receptor attachment. Residues related to the antigenic properties of the virus are found on the threefold protrusions. Some of the amino termini of VP-2 run to the exterior in full but not empty virions, which is consistent with the observation that some VP-2 polypeptides in full particles can be cleaved by trypsin. Eleven nucleotides are seen in each of 60 symmetry-related pockets on the interior surface of the capsid and together account for 13 percent of the genome.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tsao, J -- Chapman, M S -- Agbandje, M -- Keller, W -- Smith, K -- Wu, H -- Luo, M -- Smith, T J -- Rossmann, M G -- Compans, R W -- New York, N.Y. -- Science. 1991 Mar 22;251(5000):1456-64.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2006420" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Antigens, Viral/chemistry ; Capsid/ultrastructure ; Crystallography ; DNA, Viral/ultrastructure ; Hemagglutinins, Viral/chemistry ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; Parvoviridae/*ultrastructure ; Virion/ultrastructure ; Virus Replication ; X-Ray Diffraction
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    Critical structural elements of the VP16 transcriptional activation domain (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-01-04
    Description: Virion protein 16 (VP16) of herpes simplex virus type 1 contains an acidic transcriptional activation domain. Missense mutations within this domain have provided insights into the structural elements critical for its function. Net negative charge contributed to, but was not sufficient for, transcriptional activation by VP16. A putative amphipathic alpha helix did not appear to be an important structural component of the activation domain. A phenylalanine residue at position 442 was exquisitely sensitive to mutation. Transcriptional activators of several classes contain hydrophobic amino acids arranged in patterns resembling that of VP16. Therefore, the mechanism of transcriptional activation by VP16 and other proteins may involve both ionic and specific hydrophobic interactions with target molecules.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cress, W D -- Triezenberg, S J -- AI 27323/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1991 Jan 4;251(4989):87-90.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Michigan State University, East Lansing 48824-1319.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1846049" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; *Immediate-Early Proteins ; Molecular Sequence Data ; Mutation ; Protein Conformation ; *Simplexvirus ; Structure-Activity Relationship ; Transcription Factors/*chemistry/genetics/pharmacology ; Transcription, Genetic/*drug effects ; Transfection ; Viral Proteins/*genetics ; Virion
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    Membrane-mediated assembly of filamentous bacteriophage Pf1 coat protein (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-05-31
    Description: Filamentous bacteriophage Pf1 assembles by a membrane-mediated process during which the viral DNA is secreted through the membrane while being encapsulated by the major coat protein. Neutron diffraction studies showed that in the virus most of the coat protein consists of two alpha-helical segments arranged end-to-end with an intervening mobile surface loop. Nuclear magnetic resonance studies of the coat protein in the membrane-bound form have shown that the secondary structure is essentially identical to that in the intact virus. A comparison indicates that during membrane-mediated viral assembly, while the secondary structure of the coat protein is largely conserved, its tertiary structure changes substantially.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nambudripad, R -- Stark, W -- Opella, S J -- Makowski, L -- New York, N.Y. -- Science. 1991 May 31;252(5010):1305-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, Boston University, MA 02215.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1925543" target="_blank"〉PubMed〈/a〉
    Keywords: Bacteriophages/chemistry ; Capsid/*chemistry/metabolism ; *Capsid Proteins ; Cell Membrane/*metabolism ; Hydrogen Bonding ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Structure ; Neutrons ; Protein Conformation
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  • 73
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    Tissue-specific splicing in vivo of the beta-tropomyosin gene: dependence on an RNA secondary structure (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-06-28
    Description: The beta-tropomyosin gene in chicken contains two mutually exclusive exons (exons 6A and 6B) which are used by the splicing apparatus in myogenic cells, respectively, before (myoblast stage) and after (myotube stage) differentiation. The myoblast splicing pattern is shown to depend on multiple sequence elements that are located in the upstream intron and in the exon 6B and that exert a negative control over exon 6B splicing. This regulation of splicing is due, at least in part, to a secondary structure of the primary transcript, which limits in vivo the accessibility of exon 6B in myoblasts.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Libri, D -- Piseri, A -- Fiszman, M Y -- New York, N.Y. -- Science. 1991 Jun 28;252(5014):1842-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut Pasteur, Paris, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2063196" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Chickens ; Exons ; Introns ; Models, Molecular ; Molecular Sequence Data ; Muscles/physiology ; Mutagenesis, Site-Directed ; Nucleic Acid Conformation ; RNA Precursors/*genetics ; *RNA Splicing ; RNA, Messenger/*genetics ; Transcription, Genetic ; Tropomyosin/*genetics
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    Cooperativity induced by a single mutation at the subunit interface of a dimeric enzyme: glutathione reductase (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-11-13
    Description: When glycine418 of Escherichia coli glutathione reductase, which is in a closely packed region of the dimer interface, is replaced with a bulky tryptophan residue, the enzyme becomes highly cooperative (Hill coefficient 1.76) for glutathione binding. The cooperativity is lost when the mutant subunit is hybridized with a wild-type subunit to create a heterodimer. The mutation appears to disrupt atomic packing at the dimer interface, which induces a change of kinetic mechanism. A single mutation in a region of the protein remote from the active site can thus act as a molecular switch to confer cooperativity on an enzyme.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Scrutton, N S -- Deonarain, M P -- Berry, A -- Perham, R N -- New York, N.Y. -- Science. 1992 Nov 13;258(5085):1140-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Cambridge, United Kingdom.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1439821" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Binding Sites ; Escherichia coli/*enzymology/genetics ; Genes, Bacterial ; Glutathione/metabolism ; Glutathione Reductase/*chemistry/genetics/metabolism ; Glycine/chemistry ; Kinetics ; Macromolecular Substances ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; *Mutagenesis, Site-Directed ; NADP/metabolism ; Plasmids ; Protein Multimerization ; Tryptophan/chemistry
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    Actin constitution: guaranteeing the right to assemble (1992)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1992-10-30
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wertman, K F -- Drubin, D G -- GM42759/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1992 Oct 30;258(5083):759-60.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cell Biology, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1439782" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/*chemistry/genetics/metabolism ; Adenosine Diphosphate/metabolism ; Adenosine Triphosphate/metabolism ; Amino Acid Sequence ; Animals ; Binding Sites ; Models, Molecular ; Molecular Structure ; Mutation ; Rabbits ; Tetrahymena/chemistry
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    Three-dimensional structure of dimeric human recombinant macrophage colony-stimulating factor (1992)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1992-11-20
    Description: Macrophage colony-stimulating factor (M-CSF) triggers the development of cells of the monocyte-macrophage lineage and has a variety of stimulatory effects on mature cells of this class. The biologically active form of M-CSF is a disulfide-linked dimer that activates an intrinsic tyrosine kinase activity on the M-CSF receptor by inducing dimerization of the receptor molecules. The structure of a recombinant human M-CSF dimer, determined at 2.5 angstroms by x-ray crystallography, contains two bundles of four alpha helices laid end-to-end, with an interchain disulfide bond. Individual monomers of M-CSF show a close structural similarity to the cytokines granulocyte-macrophage colony-stimulating factor and human growth hormone. Both of these cytokines are monomeric in their active form, and their specific receptors lack intrinsic tyrosine kinase activity. The similarity of these structures suggests that the receptor binding determinants for all three cytokines may be similar.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pandit, J -- Bohm, A -- Jancarik, J -- Halenbeck, R -- Koths, K -- Kim, S H -- New York, N.Y. -- Science. 1992 Nov 20;258(5086):1358-62.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Structural Biology Division, Lawrence Berkeley Laboratory, Berkeley, CA 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1455231" target="_blank"〉PubMed〈/a〉
    Keywords: Crystallography ; Disulfides ; Granulocyte-Macrophage Colony-Stimulating Factor/ultrastructure ; Growth Hormone/chemistry ; Macrophage Colony-Stimulating Factor/*ultrastructure ; Models, Molecular ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Recombinant Proteins/ultrastructure ; Sequence Homology, Amino Acid ; X-Ray Diffraction
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    Predicted structural similarities of the DNA binding domains of c-Myc and endonuclease Eco RI (1992)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1992-01-24
    Description: The c-Myc oncoprotein belongs to a family of proteins whose DNA binding domains contain a basic region-helix-loop-helix (bHLH) motif. Systematic mutagenesis of c-Myc revealed that dimerized bHLH motifs formed a parallel four-helix bundle with the amino termini of helices 1 and 2 directed toward the inner and outer nucleotides of the DNA binding site, respectively. Both the basic region and the carboxyl-terminal end of the loop contributed to DNA binding specificity. The DNA binding domain of c-Myc may therefore be structurally similar to that of restriction endonuclease Eco RI.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Halazonetis, T D -- Kandil, A N -- New York, N.Y. -- Science. 1992 Jan 24;255(5043):464-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cancer Research, Merck Sharp and Dohme Research Laboratories, West Point, PA 19486.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1734524" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Binding Sites ; DNA-Binding Proteins/*chemistry ; Deoxyribonuclease EcoRI/*chemistry ; Humans ; Macromolecular Substances ; Models, Molecular ; Molecular Sequence Data ; Nucleic Acid Conformation ; Protein Conformation ; Proto-Oncogene Proteins c-myc/*chemistry ; Sequence Alignment ; Transcription Factors/chemistry
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    Converting trypsin to chymotrypsin: the role of surface loops (1992)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1992-03-06
    Description: Trypsin (Tr) and chymotrypsin (Ch) have similar tertiary structures, yet Tr cleaves peptides at arginine and lysine residues and Ch prefers large hydrophobic residues. Although replacement of the S1 binding site of Tr with the analogous residues of Ch is sufficient to transfer Ch specificity for ester hydrolysis, specificity for amide hydrolysis is not transferred. Trypsin is converted to a Ch-like protease when the binding pocket alterations are further modified by exchange of the Ch surface loops 185 through 188 and 221 through 225 for the analogous Tr loops. These loops are not structural components of either the S1 binding site or the extended substrate binding sites. This mutant enzyme is equivalent to Ch in its catalytic rate, but its substrate binding is impaired. Like Ch, this mutant utilizes extended substrate binding to accelerate catalysis, and substrate discrimination occurs during the acylation step rather than in substrate binding.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hedstrom, L -- Szilagyi, L -- Rutter, W J -- DK21344/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1992 Mar 6;255(5049):1249-53.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Hormone Research Institute, University of California, San Francisco 94143-0534.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1546324" target="_blank"〉PubMed〈/a〉
    Keywords: Acylation ; Amino Acid Sequence ; Base Sequence ; Binding Sites ; Chymotrypsin/*chemistry/metabolism ; Hydrolysis ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; Mutagenesis, Site-Directed ; Protein Conformation ; Substrate Specificity ; Trypsin/*chemistry/genetics/metabolism
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  • 79
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    Molecular structure of charybdotoxin, a pore-directed inhibitor of potassium ion channels (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-08-13
    Description: The three-dimensional structure of charybdotoxin, a high-affinity peptide blocker of several potassium ion channels, was determined by two-dimensional nuclear magnetic resonance (2-D NMR) spectroscopy. Unambiguous NMR assignments of backbone and side chain hydrogens were made for all 37 amino acids. The structure was determined by distance geometry and refined by nuclear Overhauser and exchange spectroscopy back calculation. The peptide is built on a foundation of three antiparallel beta strands to which other parts of the sequence are attached by three disulfide bridges. The overall shape is roughly ellipsoidal, with axes of approximately 2.5 and 1.5 nanometers. Nine of the ten charged groups are located on one side of the ellipsoid, with seven of the eight positive residues lying in a stripe 2.5 nanometers in length. The other side displays three hydrophobic residues projecting prominently into aqueous solution. The structure rationalizes several mechanistic features of charybdotoxin block of the high-conductance Ca2(+)-activated K+ channel.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Massefski, W Jr -- Redfield, A G -- Hare, D R -- Miller, C -- GM-20168/GM/NIGMS NIH HHS/ -- GM-31768/GM/NIGMS NIH HHS/ -- RR0031/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 3;249(4968):521-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Graduate Department of Biochemistry, Brandeis University, Waltham, MA 02254.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1696395" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Charybdotoxin ; Disulfides/analysis ; Magnetic Resonance Spectroscopy/methods ; Models, Molecular ; Molecular Sequence Data ; Potassium Channels/drug effects ; Protein Conformation ; *Scorpion Venoms/pharmacology
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  • 80
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    Emerging viruses, emerging threat (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-01-19
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Culliton, B J -- New York, N.Y. -- Science. 1990 Jan 19;247(4940):279-80.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2153314" target="_blank"〉PubMed〈/a〉
    Keywords: Acquired Immunodeficiency Syndrome/transmission ; Agriculture ; Animals ; Arenaviruses, New World ; Ebolavirus ; Hiv ; Hemorrhagic Fevers, Viral/transmission ; Herpesvirus 6, Human ; Humans ; Influenza A virus/genetics ; Influenza, Human/mortality/transmission ; Mutation ; Virus Diseases/epidemiology/etiology/*transmission ; Viruses/genetics/pathogenicity
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 81
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    Zinc mediation of the binding of human growth hormone to the human prolactin receptor (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-12-21
    Description: Human growth hormone (hGH) elicits a diverse set of biological activities including lactation that derives from binding to the prolactin (PRL) receptor. The binding affinity of hGH for the extracellular binding domain of the hPRL receptor (hPRLbp) was increased about 8000-fold by addition of 50 micromolar ZnCl2. Zinc was not required for binding of hGH to the hGH binding protein (hGHbp) or for binding of hPRL to the hPRLbp. Other divalent metal ions (Ca2+, Mg2+, Cu2+, Mn2+, and Co2+) at physiological concentrations did not support such strong binding. Scatchard analysis indicated a stoichiometry of one Zn2+ per hGH.hPRLbp complex. Mutational analysis showed that a cluster of three residues (His18, His21, and Glu174) in hGH and His188 from the hPRLbp (conserved in all PRL receptors but not GH receptors) are probable Zn2+ ligands. This polypeptide hormone.receptor "zinc sandwich" provides a molecular mechanism to explain why nonprimate GHs are not lactogenic and offers a molecular link between zinc deficiency and its association with altered functions of hGH.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cunningham, B C -- Bass, S -- Fuh, G -- Wells, J A -- New York, N.Y. -- Science. 1990 Dec 21;250(4988):1709-12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Protein Engineering, Genentech, Inc., South San Francisco, CA 94080.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2270485" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Binding Sites ; Chlorides/*pharmacology ; Growth Hormone/*metabolism ; Humans ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Oligonucleotide Probes ; Plasmids ; Protein Conformation ; Receptors, Prolactin/drug effects/genetics/*metabolism ; Restriction Mapping ; Zinc/metabolism/*pharmacology ; *Zinc Compounds
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  • 82
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    Transplanted suprachiasmatic nucleus determines circadian period (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-02-23
    Description: The pacemaker role of the suprachiasmatic nucleus in a mammalian circadian system was tested by neural transplantation by using a mutant strain of hamster that shows a short circadian period. Small neural grafts from the suprachiasmatic region restored circadian rhythms to arrhythmic animals whose own nucleus had been ablated. The restored rhythms always exhibited the period of the donor genotype regardless of the direction of the transplant or genotype of the host. The basic period of the overt circadian rhythm therefore is determined by cells of the suprachiasmatic region.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ralph, M R -- Foster, R G -- Davis, F C -- Menaker, M -- HD13162/HD/NICHD NIH HHS/ -- HD18686/HD/NICHD NIH HHS/ -- MH09483/MH/NIMH NIH HHS/ -- New York, N.Y. -- Science. 1990 Feb 23;247(4945):975-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, University of Virginia, Charlottesville 22903.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2305266" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Circadian Rhythm/genetics/*physiology ; Cricetinae ; Immunohistochemistry ; Male ; Mutation ; Nerve Tissue/*transplantation ; Neuropeptide Y/analysis ; Suprachiasmatic Nucleus/embryology/*physiology ; Vasopressins/analysis
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    The MerR metalloregulatory protein binds mercuric ion as a tricoordinate, metal-bridged dimer (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-02-23
    Description: Bacterial MerR proteins are dimeric DNA-binding proteins that mediate the Hg(II)-dependent induction of mercury resistance operons. Site-directed mutagenesis of the Bacillus sp. RC607 MerR protein reveals that three of four Cys residues per monomer are required for Hg(II) binding at the single high-affinity binding site. Inactive mutant homodimers can exchange subunits to form heterodimers active for Hg(II) binding. Studies of a heterodimer retaining only three of eight cysteine residues per dimer reveal that Cys79 in one subunit and Cys114 and Cys123 in the second subunit are necessary and sufficient for high-affinity Hg(II) binding in an asymmetric, subunit bridging coordination complex.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Helmann, J D -- Ballard, B T -- Walsh, C T -- GM20011/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Feb 23;247(4945):946-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2305262" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacillus/*analysis/genetics ; Bacterial Proteins/genetics/*metabolism ; Base Sequence ; Binding Sites ; Cations ; DNA-Binding Proteins/genetics/*metabolism ; Macromolecular Substances ; Mercury/*metabolism ; Molecular Sequence Data ; Mutation ; Structure-Activity Relationship
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    Down to the wire for the NF gene (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-07-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Roberts, L -- New York, N.Y. -- Science. 1990 Jul 20;249(4966):236-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2115688" target="_blank"〉PubMed〈/a〉
    Keywords: DNA/genetics ; *Genes ; Humans ; Mutation ; Neurofibromatosis 1/*genetics ; Suppression, Genetic
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  • 85
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    Structural mutations of the T cell receptor zeta chain and its role in T cell activation (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-07-13
    Description: T cell hybridomas that express zeta zeta, but not zeta eta, dimers in their T cell receptors (TCRs) produce interleukin-2 (IL-2) and undergo an inhibition of spontaneous growth when activated by antigen, antibodies to the receptor, or antibodies to Thy-1. Hybridomas without zeta and eta were reconstituted with mutated zeta chains. Cytoplasmic truncations of up to 40% of the zeta molecule reconstituted normal surface assembly of TCRs, but antigen-induced IL-2 secretion and growth inhibition were lost. In contrast, cross-linking antibodies to the TCR activated these cells. A point mutation conferred the same signaling phenotype as did the truncations and caused defective antigen-induced tyrosine kinase activation. Thus zeta allows the binding of antigen/major histocompatibility complex (MHC) to alpha beta to effect TCR signaling.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Frank, S J -- Niklinska, B B -- Orloff, D G -- Mercep, M -- Ashwell, J D -- Klausner, R D -- New York, N.Y. -- Science. 1990 Jul 13;249(4965):174-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2371564" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Cross-Linking Reagents ; Dose-Response Relationship, Immunologic ; Hybridomas ; Immunity, Cellular ; Immunoblotting ; Interleukin-2/*biosynthesis ; Ligands ; *Lymphocyte Activation ; Major Histocompatibility Complex ; Mice ; Molecular Sequence Data ; Mutation ; Peptide Fragments/genetics/*immunology ; Precipitin Tests ; Receptors, Antigen, T-Cell/genetics/*immunology ; Signal Transduction ; T-Lymphocytes/*immunology ; Transfection
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  • 86
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    Rhodopsin mutants that bind but fail to activate transducin (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-10-05
    Description: Rhodopsin is a member of a family of receptors that contain seven transmembrane helices and are coupled to G proteins. The nature of the interactions between rhodopsin mutants and the G protein, transduction (Gt), was investigated by flash photolysis in order to monitor directly Gt binding and dissociation. Three mutant opsins with alterations in their cytoplasmic loops bound 11-cis-retinal to yield pigments with native rhodopsin absorption spectra, but they failed to stimulate the guanosine triphosphatase activity of Gt. The opsin mutations included reversal of a charged pair conserved in all G protein-coupled receptors at the cytoplasmic border of the third transmembrane helix (mutant CD1), replacement of 13 amino acids in the second cytoplasmic loop (mutant CD2), and deletion of 13 amino acids from the third cytoplasmic loop (mutant EF1). Whereas mutant CD1 failed to bind Gt, mutants CD2 and EF1 showed normal Gt binding but failed to release Gt in the presence of guanosine triphosphate. Therefore, it appears that at least the second and third cytoplasmic loops of rhodopsin are required for activation of bound Gt.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Franke, R R -- Konig, B -- Sakmar, T P -- Khorana, H G -- Hofmann, K P -- New York, N.Y. -- Science. 1990 Oct 5;250(4977):123-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2218504" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Cell Line ; Cell Membrane/metabolism ; Chromosome Deletion ; Micelles ; Models, Molecular ; Molecular Sequence Data ; *Mutation ; Photolysis ; Protein Binding ; Protein Conformation ; Rhodopsin/genetics/*metabolism ; Transducin/*metabolism ; Transfection
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    Genetic mechanisms of tumor suppression by the human p53 gene (1990)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1990-12-14
    Description: Mutations of the gene encoding p53, a 53-kilodalton cellular protein, are found frequently in human tumor cells, suggesting a crucial role for this gene in human oncogenesis. To model the stepwise mutation or loss of both p53 alleles during tumorigenesis, a human osteosarcoma cell line, Saos-2, was used that completely lacked endogenous p53. Single copies of exogenous p53 genes were then introduced by infecting cells with recombinant retroviruses containing either point-mutated or wild-type versions of the p53 cDNA sequence. Expression of wild-type p53 suppressed the neoplastic phenotype of Saos-2 cells, whereas expression of mutated p53 conferred a limited growth advantage to cells in the absence of wild-type p53. Wild-type p53 was phenotypically dominant to mutated p53 in a two-allele configuration. These results suggest that, as with the retinoblastoma gene, mutation of both alleles of the p53 gene is essential for its role in oncogenesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, P L -- Chen, Y M -- Bookstein, R -- Lee, W H -- CA51495/CA/NCI NIH HHS/ -- EY00278/EY/NEI NIH HHS/ -- EY05758/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 14;250(4987):1576-80.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, School of Medicine, University of California, San Diego, La Jolla 92093-0612.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2274789" target="_blank"〉PubMed〈/a〉
    Keywords: Alleles ; Base Sequence ; *Cinnamates ; Cloning, Molecular ; DNA/genetics ; Drug Resistance/genetics ; Genes, p53/*genetics ; Genetic Vectors ; Humans ; Hygromycin B/analogs & derivatives ; Molecular Sequence Data ; Moloney murine leukemia virus/genetics ; Mutation ; Neomycin ; Osteosarcoma/*genetics ; Plasmids ; Transfection ; Tumor Cells, Cultured
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  • 88
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    Secondary structure is the major determinant for interaction of HIV rev protein with RNA (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-02-16
    Description: A region in the human immunodeficiency virus (HIV) env message, with the potential to form a complex secondary structure (designated RRE), interacts with the rev protein (Rev). This interaction is believed to mediate export of HIV structural messenger RNAs from the nucleus to the cytoplasm. In this report the regions essential for Rev interaction with the RRE are further characterized and the functional significance of Rev-RRE interaction in vivo is examined. A single hairpin loop structure within the RRE was found to be a primary determinant for Rev binding in vitro and Rev response in vivo. Maintenance of secondary structure, rather than primary nucleotide sequence alone, appeared to be necessary for Rev-RNA interaction, which distinguishes it from the mechanism for cis-acting elements in DNA. Limited changes within the 200 nucleotides, which preserved the proper RRE conformational structure, were well tolerated for Rev binding and function. Thus, variation among the RRE elements present in the diverse HIV isolates would have little, if any, effect on Rev responsiveness.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Olsen, H S -- Nelbock, P -- Cochrane, A W -- Rosen, C A -- New York, N.Y. -- Science. 1990 Feb 16;247(4944):845-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Oncology and Virology, Roche Institute of Molecular Biology, Nutley, NJ 07110.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2406903" target="_blank"〉PubMed〈/a〉
    Keywords: Base Composition ; Base Sequence ; Chromosome Deletion ; Gene Products, rev/genetics/*metabolism ; Genes, rev ; HIV/*genetics/metabolism ; Molecular Sequence Data ; Mutation ; Nucleic Acid Conformation ; Plasmids ; Protein Conformation ; RNA, Messenger/*genetics/metabolism ; RNA, Viral/genetics/metabolism ; Trans-Activators/*metabolism ; rev Gene Products, Human Immunodeficiency Virus
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  • 89
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    Interfacial catalysis: the mechanism of phospholipase A2 (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-12-14
    Description: A chemical description of the action of phospholipase A2 (PLA2) can now be inferred with confidence from three high-resolution x-ray crystal structures. The first is the structure of the PLA2 from the venom of the Chinese cobra (Naja naja atra) in a complex with a phosphonate transition-state analogue. This enzyme is typical of a large, well-studied homologous family of PLA2S. The second is a similar complex with the evolutionarily distant bee-venom PLA2. The third structure is the uninhibited PLA2 from Chinese cobra venom. Despite the different molecular architectures of the cobra and bee-venom PLA2s, the transition-state analogue interacts in a nearly identical way with the catalytic machinery of both enzymes. The disposition of the fatty-acid side chains suggests a common access route of the substrate from its position in the lipid aggregate to its productive interaction with the active site. Comparison of the cobra-venom complex with the uninhibited enzyme indicates that optimal binding and catalysis at the lipid-water interface is due to facilitated substrate diffusion from the interfacial binding surface to the catalytic site rather than an allosteric change in the enzyme's structure. However, a second bound calcium ion changes its position upon the binding of the transition-state analogue, suggesting a mechanism for augmenting the critical electrophile.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3443688/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3443688/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Scott, D L -- White, S P -- Otwinowski, Z -- Yuan, W -- Gelb, M H -- Sigler, P B -- GM22324/GM/NIGMS NIH HHS/ -- HL36235/HL/NHLBI NIH HHS/ -- R01 HL036235/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 14;250(4987):1541-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2274785" target="_blank"〉PubMed〈/a〉
    Keywords: Bee Venoms/analysis ; Binding Sites ; Calcium/metabolism ; Catalysis ; Chemistry, Physical ; Cobra Venoms/analysis ; Models, Molecular ; Molecular Structure ; Organophosphonates/metabolism ; Phospholipases A/chemistry/*metabolism ; Phospholipases A2 ; Phospholipids/metabolism ; Physicochemical Phenomena ; Protein Conformation ; X-Ray Diffraction
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    Poliovirus mutants resistant to neutralization with soluble cell receptors (1990)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1990-12-14
    Description: Poliovirus mutants resistant to neutralization with soluble cellular receptor were isolated. Replication of soluble receptor-resistant (srr) mutants was blocked by a monoclonal antibody directed against the HeLa cell receptor for poliovirus, indicating that the mutants use this receptor to enter cells. The srr mutants showed reduced binding to HeLa cells and cell membranes. However, the reduced binding phenotype did not have a major impact on viral replication, as judged by plaque size and one-step growth curves. These results suggest that the use of soluble receptors as antiviral agents could lead to the selection of neutralization-resistant mutants that are able to bind cell surface receptors, replicate, and cause disease.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kaplan, G -- Peters, D -- Racaniello, V R -- AI20017/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 14;250(4987):1596-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2177226" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Monoclonal/immunology ; Antiviral Agents ; Baculoviridae/genetics ; Cell Line ; Cell Membrane/metabolism ; Centrifugation, Density Gradient ; DNA/genetics ; Genetic Vectors ; HeLa Cells ; Humans ; Insects ; Mutation ; Neutralization Tests ; Poliovirus/genetics/*physiology ; Receptors, Virus/genetics/*physiology ; Recombinant Proteins/physiology ; Transfection ; Virus Replication
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    Three-dimensional structure of the LDL receptor-binding domain of human apolipoprotein E (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-06-28
    Description: Human apolipoprotein E, a blood plasma protein, mediates the transport and uptake of cholesterol and lipid by way of its high affinity interaction with different cellular receptors, including the low-density lipoprotein (LDL) receptor. The three-dimensional structure of the LDL receptor-binding domain of apoE has been determined at 2.5 angstrom resolution by x-ray crystallography. The protein forms an unusually elongated (65 angstroms) four-helix bundle, with the helices apparently stabilized by a tightly packed hydrophobic core that includes leucine zipper-type interactions and by numerous salt bridges on the mostly charged surface. Basic amino acids important for LDL receptor binding are clustered into a surface patch on one long helix. This structure provides the basis for understanding the behavior of naturally occurring mutants that can lead to atherosclerosis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wilson, C -- Wardell, M R -- Weisgraber, K H -- Mahley, R W -- Agard, D A -- HL-41633/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1991 Jun 28;252(5014):1817-22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, University of California, San Francisco 94143-0448.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2063194" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Apolipoproteins E/*chemistry/genetics/metabolism ; Binding Sites ; Computer Graphics ; Humans ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Receptors, LDL/*metabolism ; X-Ray Diffraction
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  • 92
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    Structure of a legume lectin with an ordered N-linked carbohydrate in complex with lactose (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-11-08
    Description: The three-dimensional structure of the lactose complex of the Erythrina corallodendron lectin (EcorL), a dimer of N-glycosylated subunits, was determined crystallographically and refined at 2.0 angstrom resolution to an R value of 0.19. The tertiary structure of the subunit is similar to that of other legume lectins, but interference by the bulky N-linked heptasaccharide, which is exceptionally well ordered in the crystal, forces the EcorL dimer into a drastically different quaternary structure. Only the galactose moiety of the lactose ligand resides within the combining site. The galactose moiety is oriented differently from ligands in the mannose-glucose specific legume lectins and is held by hydrophobic interactions with Ala88, Tyr106, Phe131, and Ala218 and by seven hydrogen bonds, four of which are to the conserved Asp89, Asn133, and NH of Gly107. The specificity of legume lectins toward the different C-4 epimers appears to be associated with extensive variations in the outline of the variable parts of the binding sites.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shaanan, B -- Lis, H -- Sharon, N -- New York, N.Y. -- Science. 1991 Nov 8;254(5033):862-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1948067" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Carbohydrate Conformation ; Carbohydrate Sequence ; Computer Simulation ; Erythrina ; Glycosylation ; Hydrogen Bonding ; Lectins/*chemistry ; Macromolecular Substances ; Models, Molecular ; Molecular Sequence Data ; Oligosaccharides ; Plant Lectins ; Plants, Medicinal ; Protein Conformation ; X-Ray Diffraction
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 93
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    Atomic structure of adenosine deaminase complexed with a transition-state analog: understanding catalysis and immunodeficiency mutations (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-05-31
    Description: The crystal structure of a murine adenosine deaminase complexed with 6-hydroxyl-1,6-dihydropurine ribonucleoside, a nearly ideal transition-state analog, has been determined and refined at 2.4 angstrom resolution. The structure is folded as an eight-stranded parallel alpha/beta barrel with a deep pocket at the beta-barrel COOH-terminal end wherein the inhibitor and a zinc are bound and completely sequestered. The presence of the zinc cofactor and the precise structure of the bound analog were not previously known. The 6R isomer of the analog is very tightly held in place by the coordination of the 6-hydroxyl to the zinc and the formation of nine hydrogen bonds. On the basis of the structure of the complex a stereoselective addition-elimination or SN2 mechanism of the enzyme is proposed with the zinc atom and the Glu and Asp residues playing key roles. A molecular explanation of a hereditary disease caused by several point mutations of an enzyme is also presented.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wilson, D K -- Rudolph, F B -- Quiocho, F A -- CA14030/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1991 May 31;252(5010):1278-84.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1925539" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Deaminase/*chemistry/deficiency/metabolism ; Amino Acid Sequence ; Animals ; Binding Sites ; Catalysis ; Crystallization ; Immunologic Deficiency Syndromes/*enzymology/genetics ; Mice ; Models, Molecular ; Molecular Structure ; Mutation ; Protein Conformation ; Purine Nucleosides/chemistry/*metabolism ; Ribonucleosides/chemistry/*metabolism ; Zinc/metabolism
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  • 94
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    NMR studies of the structure and dynamics of membrane-bound bacteriophage Pf1 coat protein (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-05-31
    Description: Filamentous bacteriophage coat protein undergoes a remarkable structural transition during the viral assembly process as it is transferred from the membrane environment of the cell, where it spans the phospholipid bilayer, to the newly extruded virus particles. Nuclear magnetic resonance (NMR) studies show the membrane-bound form of the 46-residue Pf1 coat protein to be surprisingly complex with five distinct regions. The secondary structure consists of a long hydrophobic helix (residues 19 to 42) that spans the bilayer and a short amphipathic helix (residues 6 to 13) parallel to the plane of the bilayer. The NH2-terminus (residues 1 to 5), the COOH-terminus (residues 43 to 46), and residues 14 to 18 connecting the two helices are mobile. By comparing the structure and dynamics of the membrane-bound coat protein with that of the viral form as determined by NMR and neutron diffraction, essential features of assembly process can be identified.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shon, K J -- Kim, Y -- Colnago, L A -- Opella, S J -- AI20770-06/AI/NIAID NIH HHS/ -- GM34343-06/GM/NIGMS NIH HHS/ -- RR-02301/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1991 May 31;252(5010):1303-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Pennsylvania, Philadelphia 19104.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1925542" target="_blank"〉PubMed〈/a〉
    Keywords: Capsid/*chemistry/metabolism ; *Capsid Proteins ; Cell Membrane/metabolism ; Lipid Bilayers/metabolism ; *Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Structure ; Protein Conformation
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  • 95
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    Long-range structure in ribonuclease P RNA (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-11-08
    Description: Phylogenetic-comparative and mutational analyses were used to elucidate the structure of the catalytically active RNA component of eubacterial ribonuclease P (RNase P). In addition to the refinement and extension of known structural elements, the analyses revealed a long-range interaction that results in a second pseudoknot in the RNA. This feature strongly constrains the three-dimensional structure of RNase P RNA near the active site. Some RNase P RNAs lack this structure but contain a unique, possibly compensating, structural domain. This suggests that different RNA structures located at different positions in the sequence may have equivalent architectural functions in RNase P RNA.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Haas, E S -- Morse, D P -- Brown, J W -- Schmidt, F J -- Pace, N R -- GM34527/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1991 Nov 8;254(5033):853-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Indiana University, Bloomington 47405.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1719634" target="_blank"〉PubMed〈/a〉
    Keywords: Bacillus subtilis/enzymology/genetics ; Base Composition ; Base Sequence ; Biological Evolution ; Endoribonucleases/*genetics ; Escherichia coli/enzymology/genetics ; *Escherichia coli Proteins ; Models, Molecular ; Molecular Sequence Data ; Mutagenesis ; Nucleic Acid Conformation ; RNA, Bacterial/*genetics ; RNA, Catalytic/*genetics ; Ribonuclease P
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  • 96
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    Zinc finger-DNA recognition: crystal structure of a Zif268-DNA complex at 2.1 A (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-05-10
    Description: The zinc finger DNA-binding motif occurs in many proteins that regulate eukaryotic gene expression. The crystal structure of a complex containing the three zinc fingers from Zif268 (a mouse immediate early protein) and a consensus DNA-binding site has been determined at 2.1 angstroms resolution and refined to a crystallographic R factor of 18.2 percent. In this complex, the zinc fingers bind in the major groove of B-DNA and wrap part way around the double helix. Each finger has a similar relation to the DNA and makes its primary contacts in a three-base pair subsite. Residues from the amino-terminal portion of an alpha helix contact the bases, and most of the contracts are made with the guanine-rich strand of the DNA. This structure provides a framework for understanding how zinc fingers recognize DNA and suggests that this motif may provide a useful basis for the design of novel DNA-binding proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pavletich, N P -- Pabo, C O -- GM-31471/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1991 May 10;252(5007):809-17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2028256" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Crystallography ; DNA/*metabolism ; DNA-Binding Proteins/*chemistry/isolation & purification/physiology ; Early Growth Response Protein 1 ; *Immediate-Early Proteins ; Mice ; Models, Molecular ; Molecular Sequence Data ; Molecular Structure ; Transcription Factors/*chemistry/isolation & purification/physiology ; Zinc Fingers/*physiology
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  • 97
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    Structurally homologous ligand binding of integrin Mac-1 and viral glycoprotein C receptors (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-11-22
    Description: Three spatially distant surface loops were found to mediate the interaction of the coagulation protein factor X with the leukocyte integrin Mac-1. This interacting region, which by computational modeling defines a three-dimensional macromotif in the catalytic domain, was also recognized by glycoprotein C (gC), a factor X receptor expressed on herpes simplex virus (HSV)-infected endothelial cells. Peptidyl mimicry of each loop inhibited factor X binding to Mac-1 and gC, blocked monocyte generation of thrombin, and prevented monocyte adhesion to HSV-infected endothelium. These data link the ligand recognition of Mac-1 to established mechanisms of receptor-mediated vascular injury.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Altieri, D C -- Etingin, O R -- Fair, D S -- Brunck, T K -- Geltosky, J E -- Hajjar, D P -- Edgington, T S -- HL 46408/HL/NHLBI NIH HHS/ -- P01 HL 16411/HL/NHLBI NIH HHS/ -- R01 HL 43773/HL/NHLBI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1991 Nov 22;254(5035):1200-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Immunology, Scripps Research Institute, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1957171" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding, Competitive ; Cell Line ; Factor X/*metabolism/ultrastructure ; Humans ; In Vitro Techniques ; Ligands ; Macrophage-1 Antigen/*metabolism ; Models, Molecular ; Molecular Sequence Data ; Peptides/chemistry/metabolism ; Protein Conformation ; Viral Envelope Proteins/*metabolism
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  • 98
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    Identification of a gene located at chromosome 5q21 that is mutated in colorectal cancers (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-03-15
    Description: Recent studies have suggested the existence of a tumor suppressor gene located at chromosome region 5q21. DNA probes from this region were used to study a panel of sporadic colorectal carcinomas. One of these probes, cosmid 5.71, detected a somatically rearranged restriction fragment in the DNA from a single tumor. Further analysis of the 5.71 cosmid revealed two regions that were highly conserved in rodent DNA. These sequences were used to identify a gene, MCC (mutated in colorectal cancer), which encodes an 829-amino acid protein with a short region of similarity to the G protein-coupled m3 muscarinic acetylcholine receptor. The rearrangement in the tumor disrupted the coding region of the MCC gene. Moreover, two colorectal tumors were found with somatically acquired point mutations in MCC that resulted in amino acid substitutions. MCC is thus a candidate for the putative colorectal tumor suppressor gene located at 5q21. Further studies will be required to determine whether the gene is mutated in other sporadic tumors or in the germ line of patients with an inherited predisposition to colonic tumorigenesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kinzler, K W -- Nilbert, M C -- Vogelstein, B -- Bryan, T M -- Levy, D B -- Smith, K J -- Preisinger, A C -- Hamilton, S R -- Hedge, P -- Markham, A -- 6M 07184/PHS HHS/ -- CA 06973/CA/NCI NIH HHS/ -- CA 09243/CA/NCI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1991 Mar 15;251(4999):1366-70.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Genetics Laboratory, Johns Hopkins Oncology Center, Baltimore, MD 21231.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1848370" target="_blank"〉PubMed〈/a〉
    Keywords: Adenomatous Polyposis Coli/*genetics ; Amino Acid Sequence ; Animals ; Base Sequence ; *Chromosomes, Human, Pair 5 ; Colorectal Neoplasms/*genetics ; Exons ; GTP-Binding Proteins/metabolism ; Gene Expression ; *Genes, Tumor Suppressor ; Humans ; Molecular Sequence Data ; Mutation ; Oligonucleotides/chemistry ; Polymerase Chain Reaction ; Proteins/*genetics/metabolism ; Rats ; Sequence Homology, Nucleic Acid ; *Tumor Suppressor Proteins
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  • 99
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    Structural basis for the activation of glycogen phosphorylase b by adenosine monophosphate (1991)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1991-11-29
    Description: The three-dimensional structure of the activated state of glycogen phosphorylase (GP) as induced by adenosine monophosphate (AMP) has been determined from crystals of pyridoxalpyrophosphoryl-GP. The same quaternary changes relative to the inactive conformation as those induced by phosphorylation are induced by AMP, although the two regulatory signals function through different local structural mechanisms. Moreover, previous descriptions of the phosphorylase active state have been extended by demonstrating that, on activation, the amino- and carboxyl-terminal domains of GP rotate apart by 5 degrees, thereby increasing access of substrates to the catalytic site. The structure also reveals previously unobserved interactions with the nucleotide that accounts for the specificity of the nucleotide binding site for AMP in preference to inosine monophosphate.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sprang, S R -- Withers, S G -- Goldsmith, E J -- Fletterick, R J -- Madsen, N B -- R01 DK26081/DK/NIDDK NIH HHS/ -- R01 DK31507/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1991 Nov 29;254(5036):1367-71.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas 75235-9050.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1962195" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Monophosphate/*pharmacology ; Amino Acid Sequence ; Binding Sites ; Enzyme Activation ; Macromolecular Substances ; Models, Molecular ; Phosphorylase b/chemistry/*metabolism ; Protein Conformation ; Pyridoxal Phosphate/analogs & derivatives/metabolism ; X-Ray Diffraction
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  • 100
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    Identity elements for specific aminoacylation of yeast tRNA(Asp) by cognate aspartyl-tRNA synthetase (1991)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1991-06-21
    Description: The nucleotides crucial for the specific aminoacylation of yeast tRNA(Asp) by its cognate synthetase have been identified. Steady-state aminoacylation kinetics of unmodified tRNA transcripts indicate that G34, U35, C36, and G73 are important determinants of tRNA(Asp) identity. Mutations at these positions result in a large decrease (19- to 530-fold) of the kinetic specificity constant (ratio of the catalytic rate constant kcat and the Michaelis constant Km) for aspartylation relative to wild-type tRNA(Asp). Mutation to G10-C25 within the D-stem reduced kcat/Km eightfold. This fifth mutation probably indirectly affects the presentation of the highly conserved G10 nucleotide to the synthetase. A yeast tRNA(Phe) was converted into an efficient substrate for aspartyl-tRNA synthetase through introduction of the five identity elements. The identity nucleotides are located in regions of tight interaction between tRNA and synthetase as shown in the crystal structure of the complex and suggest sites of base-specific contacts.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Putz, J -- Puglisi, J D -- Florentz, C -- Giege, R -- New York, N.Y. -- Science. 1991 Jun 21;252(5013):1696-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratoire de Biochimie, Institut de Biologie Moleculaire et Cellulaire du CNRS, Strasbourg, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2047878" target="_blank"〉PubMed〈/a〉
    Keywords: Aspartate-tRNA Ligase/*metabolism ; Base Sequence ; Computer Graphics ; DNA Mutational Analysis ; Fungal Proteins/metabolism ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; RNA, Fungal/metabolism ; RNA, Transfer, Amino Acyl/metabolism ; RNA, Transfer, Asp/*metabolism ; Saccharomyces cerevisiae/*enzymology ; Structure-Activity Relationship ; Substrate Specificity ; *Transfer RNA Aminoacylation
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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