ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Polymer and Materials Science  (7,462)
  • Physics  (1,395)
  • Analytical Chemistry and Spectroscopy  (1,298)
  • Cell & Developmental Biology  (1,046)
  • 1995-1999  (2,548)
  • 1980-1984  (4,380)
  • 1970-1974  (2,851)
  • 1925-1929  (31)
  • 1998  (2,548)
  • 1983  (4,380)
  • 1972  (2,851)
  • 1927  (31)
Collection
Keywords
Publisher
Years
  • 1995-1999  (2,548)
  • 1980-1984  (4,380)
  • 1970-1974  (2,851)
  • 1925-1929  (31)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Spatial configurations of polynucleotide chains. I. Steric interactions in polyribonucleotides: A virtual bond modelFrom the thesis submitted by Wilma K. Olson in fulfillment of the requirements for the degree of Doctor of Philosophy, Stanford University, 1971. (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1-23 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simplified scheme for treating the spatial configurations of polynucleotide chains is developed using the rotational isomeric state approximation and statistical methods applicable to linear systems of interacting subunits. As a consequence of geometric constraints imposed by the skeletal structure and of the severity of certain steric interactions, it is possible to represent the repeat unit comprising six skeletal bonds by two virtual bonds of fixed length. The configuration of the polynucleotide chain as a whole may be conveniently described by an alternating succession of these two virtual bonds. Moreover, analysis of steric interactions suggests that bond rotations governing the mutual orientation of a given pair of successive virtual bonds should be sensibly independent of the rotations affecting the mutual orientation of other pairs. The statistical mechanical treatment of configuration-dependent properties is much simplified in consequence of this mutual independence. Mean-square dimensions calculated by giving equal weights to all sterically allowed conformations are much smaller than values determined by Felsenfeld and co-workers. The calculated dimensions are markedly increased, however, by placing certain arbitrary restrictions on the rotations about selected pairs of skeletal bonds. It is thus demonstrated that steric interactions alone are insufficient to account for the spatial characteristics of polynucleotide chains. The dimensions are also found to be sensitive to the conformation of the ribose ring of each nucleotide unit, but, insofar as the influences of steric interactions are concerned, the dimensions do not depend on the heterocyclic base attached to the ribose ring.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Isoenzymes of tetrameric proteins (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 119-126 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A theory is presented concerning the possible arrangements of protomers in tetrameric molecules. Isoenzymes may exist even in the case of homotetramers if the asymmetry of the identical protomers is detectable. The number of tetrahedral isoenzymes that can be isolated depends on the nature of the intersubunit bonds and on the level of the asymmetry of the protomers. Five isoenzymes can be distinguished only if two different types of protomers form tetrahedral tetramers and the asymmetry of protomers is not detectable with the method used. If the two types of protomers can bind each other by any pairs of binding sets and the asymmetry of both protomer types reaches the level of detection with the method used, we obtain 117 isoenzymes: 15 individual ones, and 51 stereoisomeric pairs.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110109
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Graphical approach to non-ideal cases of self-associating protein systems (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 197-214 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Our previous paper described graphical procedures for evaluating the mode of association in ideal discrete and indefinite cases. This paper concerns the application of such procedures in cases where the non-ideality term BM1 must be considered. Bovine liver L-glutamate dehydrogenase and lysozyme are used as model systems. Several graphical procedures for dealing with cases of 1 - m, 1 - m - n, or indefinite association are developed. The procedure is based on the evaluation of the weight-fraction monomer with-out prior calculation of BM1, using graphical analysis to evaluate the non-ideality term.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110115
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Fibrillar aggregates of poly-γ-benzyl-L-glutamate (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 271-278 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110120
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Lysine oligopeptides. Preparation by ion-exchange chromatographyOn leave from the Department of Biophysics, The Weizmann Institute of Science, Rehovot, Israel. (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 607-621 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of L-lysine peptides (Lysn, n = 2-14) from polyL-lysine is described. Fractionation by ion-exchange column chromatography of poly-L-lysine hydrolysates on a preparative scale resulted in 0.2-1.0 g quantities of individual members of the poly-L-lysine series. The peptides isolated proved to be analytically pure and the optical configuration was fully retained, as demonstrated by complete enzymic digestion. Peptides higher than n = 14 were also prepared. They consisted of oligolysine groups of narrow and accurately determined size distribution. Potentiometric titrations were used both to characterize the products and to demonstrate the characteristic dependence of the dissociation constants on size of the peptide.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Independence of length and temperature effects on the rate of helix formation between complementary ribopolymers (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 549-561 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate of double helix formation by single stranded Poly A plus Poly U, Poly I plus Poly C, Poly G plus Poly C, and T2 DNA has been investigated as a function of both the length of the reacting strands and temperature. The length dependence of the rate is found to be independent of temperature. All of the reactions studied show a rate approximately proportional to the square root of the length of the shorter of the complementary strands. At or about 30°C below the melting temperature the ribopolymers react with about the same rate. This rate is four to five times slower than DNA renaturation rates. The effect of temperature on ribopolymer reaction rates is interpreted in terms of a steady-state model for helix propagation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Evidence for stereospecific collision complexes of cyclo(tri-L-prolyl) with benzene (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 653-659 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: NMR spectra of cyclo(tri-L-prolyl), c-(P)3, show large shifts of the Hα resonance on adding C6D6 to a solution of c-(P)3 in CD2Cl2. CPK models and observed coupling constants indicate a rigid c-(P)3 conformation, independent of solvent composition, suggesting that these shifts result from formation of stereospecific C6D6-c-(P)3 collision complexes in which the c-(P)3 Hα lie near the face of the aromatic ring. The temperature dependence of the Hα shifts and the solvent dependent shifts observed on adding toluene-d8 or nitrobenzene-d5 to the c-(P)3 solution suggest that preferred C6D6-c-(P)3 orientations result from attractive interactions between the electron-rich aromatic ring and the electropositive Hα's and/or δ+ nitrogen atoms in the peptide backbone. Reports of such interactions in increasingly diverse peptide model systems suggest that they may play a role in stabilizing protein structures.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110310
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Thermal denaturation of nucleohistones - effects of formaldehyde reaction (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 835-847 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal denaturation of native or partially dehistonized nucleohistones shows two melting bands at 66 and 81° in 2.5 × 10-4 M EDTA, pH 8.0. These correspond to the melting of DNA segments bound by the less basic and the more basic half-molecules of histones, respectively. These two melting bands combine into a broad melting band from around 70 to 85° when these nucleohistones are pre-treated with formaldehyde. A formaldehyde reaction which fixes histones on DNA by covalent bonds account for the effect. Formaldehyde fixation also increases the melting temperature of some free DNA segments from around 42 to around 55°. This is interpreted as a result of closed or rigid boundaries between free DNA and formaldehyde-reacted histone-bound DNA segments. MgCl2 dissociates histones from DNA more effectively and leaves longer free DNA segments than does NaCl. Thermal denaturation of a formaldehyde-reacted nucleoprotein thus provides an effective tool for comparing the relative size of free DNA regions on nucleoproteins. The effect of reversible binding of ligands on helix-coil transition of DNA is descussed and found not adequate for thermal denaturation of nucleohistones.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110408
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Linear relaxation analysis of the mechanochemical transformation of collagen fibers (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 899-912 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The isometric tensile stress generation observed when collagen fibers are immersed in aqueous solutions of lithium bromide ranging in molar concentration up to 7 was studied at 23°C. The reverse process, namely, isometric stress relaxation of the fiber occurring by subsequent immersion in distilled water, was also studied. We find that the data in the region of LiBr concentration up to about 2.5 moles/liter are adequately represented by a superposition integral \documentclass{article}\pagestyle{empty}\begin{document}$$ \sigma (t) = \int_{ - \infty }^\infty {K(t - \tau )} \frac{{dc(\tau )}}{{d\tau }}\,d\tau $$\end{document} where σ(t) is the time-dependent stress generated by the collagen fiber held at fixed length, c(t) is the history of LiBr molar concentration, and K(t) is the isometric contractility function, expressed as stress per unit salt concentration. We conclude that, within a limited range of salt concentration, a collagen fiber in a LiBr bath behaves as if it were a linear, time-invariant system defined mechanochemically by a single function K(t) which depends on the structural characteristics of the fiber while being independent of salt concentration. An analysis is presented of isometric mechanochemical data obtained under conditions of equilibrium by other workers who studied the behavior of collagen fibers in aqueous solutions either of urea, LiBr, or KCNS. The analysis shows that these independent (equilibrium) data confirm the linarity of the relation between isometric contractile stress and salt concentration on which our superposition integral representation is based. We also find that the asymptotic (infinite-time) value of the isometric stress is linearly related to the chemical potential of the salt as well, in agreement with the equilibrium thermodynamic treatment of mechanochemical processes by Katchalsky and Oplatka.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110413
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Thermodynamic analysis of thermal transitions in globular proteins. I. Calorimetric study of ribotrypsinogen, ribonuclease, and myoglobin (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 935-935 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110415
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    On the application of polyelectrolyte “limiting laws” to the helix-coil transition of DNA. I. Excess univalent cations (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 937-949 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A general theory of polyelectrolyte solutions is here used to calculate the differences in Gibbs free energy, enthalpy, and entropy between the coil and helix forms of DNA at any temperature and salt concentration. The salt has univalent cations and is assumed present in excess over the base concentration. The results are restricted to sufficiently dilute solutions. It is shown that the salt concentrations effect is entirely entropic in origin. When applied to the melting temperature, the calculations yield a relation between the enthalpy difference at the melting temperature and the slope of the plot of melting temperature vs. the logarithm of the salt concentration. In accord with observation, both the Gibbs free energy difference at any fixed temperature and the melting temperature are predicted to be linear functions of the log of the salt concentration.However, the theory is not in quantitative agreement with enthalpy data. Data on various colligative and transport properties of both helix and coil forms are reviewed in the text and in Appendix B, and good agreement is found with theory for both forms. No attempt is made to explain why the theory is quantitative for these properties but not for heat measurements.Finally, in Appendix A, an approximate calculation is made of the free energy contributions due to ionic effects not associated with the salt concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110502
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    The conformation fo poly-L-alanine in hexafluoroisopropanol (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1001-1020 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-molecular-weight poly-L-alanine dissolved in hexafluoroisopropanol exhibits infrared, ultraviolet, circular dichroism, and optical rotatory dispersion spectra which are unique and unlike any other previously reported polypeptide spectra. Strong evidence that a helical conformation is present is shown by the high degree of hypochromism in the 187mμ absorption peak and by the positions of the amide infrared bands. The CD and ORD spectra are also similar to those of α-helical polypeptides, though important qualitative and qualitative differences are observed. To explain the novel spectra, which are not mixtures of the spectra of previously reported polypeptide conformations, a new α-helix-like conformation is proposed. The postulated conformation (a doubly hydrogen-bonded helix) is a distorted α-helix in which the peptide carbonyl groups point slightly out from the helix axis and are hydrogen bonded simul taneously both to the NH of the fourth peptide residue to the carboxyl terminal side (as in the classical α-helix), as well as to a solvent molecule's hydroxyl hydrogen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110506
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    PPP calculations of the circular dichroism spectra of some dinucleoside phosphates (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1091-1102 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Circular dichriosm (CD) spectra have been calculated for serveral dinucleoside phosphates using a variant of the Pariser-Parr-Pople π-electron molecular orbital method. This method does not require the prior knowledge of the experimental absorption spectra of transition moments of the bases forming the dinucleoside phosphates. Calculated spectra were obtained in good agreement with experimental spectra for four dinucleoside phosphates, ApA, UpU, GpA, and UpA, and reasonable agreement was obtained for ApG and ApU. The effect of changing conformation on the CD spectrum was studied for ApA, UpU, UpA, and ApU; the spectra of UpU, UpA, and ApU were sensitive to small change in conformation, whereas ApA was insensitive over the range of conformation studied. Further studies await detailed knowledge of the structure of dinucleoside phosphates in solution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110511
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Synthesis and conformational study of poly(N∊-benzyl-L-lysine) and its benzyloxycarbonyl derivative (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1259-1268 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solvent-and pH-induced conformational changes are examined in order to investigate the influence of benzyl group. Polymer was prepared via N∊-benzyloxycarbonyl, N∊-benzyl-Nα-carboxy-L-lysine anhydride. The resulting poly (N∊-benzyloxycarbonyl, N∊-benzyl-L-lysine) was obtained in high yield and had a high molecular weight. The protected polymer was removed into poly (N∊-benzyl-L-lysine) by treating it with hydrogen bromide. From the results of the ORD and CD, the protected polymer has a righthanded α-helix, showing [m′]233 = -10,300, [θ]220 = -27,600 and [θ]207 = -25,100 in dioxane. The breakdown of the helical conformation is found to occur at 8% dichloroacetic acid in chloroform-dichloroacetic acid mixture. In the pH range 3.35-6.90, poly (N∊-benzyl-L-lysine) is in a random coil structure. In the pH range 7.50-13.0, the polypeptide has a right-handed α-helix structure; [m′]233 = -12,000, [0]220 = -27,200, and [0]207 = -27,000. In comparison with poly-L-lysine, the coil-to-helix transition is observed at lower pH range in 50% n-propanol. Above pH 8 by heating, the α ⇀ β transition of poly (N∊-benzyl-L-lysine) is not observed in an aqueous media.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110610
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Detection of polar side-chain hydration in polypeptides by near-infrared spectroscopy (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1305-1310 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110614
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Simple sequential model for the kinetics of conformational transitions of oligomeric helices and proteins (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1499-1520 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple sequential model is developed which is applicable to the kinetics of melting of some types of oligomeric helices and as an idealization to the kinetics of unfolding of some protein molecules. A procedure is presented for calculating the concentrations of all conformational species as functions of time. The time course of experimentally observable quantities which depend on these concentrations may then be computed.One of the most characteristic features of the model is the distinction between a transient and a steady-state phase. During the latter all molecular parameters change at the same rate, which depends strongly on the difficulty of nucleation and the length of the sequence. Simple approximations to the steady-state rate are discussed in terms of the exact solution. Rates of transient processes dependless strongly on the rate of nucleation and the number of steps and are a more direct reflection of the rates of the rates of the elementary process of propagation. The value of experimental observation of transient process is emphasized.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110713
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Masthead (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110801
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Far-infrared spectra of sequential copolymers of amino acids with alkyl group side chains (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1593-1605 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Far-infrared spectra were measured for the sequential copolymers of amino acids with alkyl group side chains. The analysis of the spectra showed that (L-Ala-L-Ala-Gly)n, (L-Ala-Gly)n, (L-Ala-Gly-Gly)n, (L-Val-L-Ala-L-Ala)n, and (L-Val-L-Ala)n, have the antiparallel pleated sheet structures and that the backbone conformations of (L-Val-L-Val-L-Ala)n and (L-Val-L-Val-Gly)n are the same as that of poly-L-valine. The far-infrared bands characteristic of the antiparallel pleated sheet structure were assigned on the basis of the result of the normal coordinate analysis of poly-L-alanine with this structure. The intersheet and interchain spacings of the sequential copolymers with the antiparallel pleated sheet structure were determined from the x-ray powder-diffraction patterns of these samples.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Induced cotton effects of tRNA-acridine orange complex and tRNA conformation (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1583-1592 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Circular dichroism spectra of acridine orange bound to E. coli tRNA were studied at varying tRNA phosphate-to-dye (P/D) ratios for both unfractionated and purified materials in the absence of Mg++. From the rather discrete features exhibited in the circular dichroism spectra three types of interactions were observed: (1) A high P/D ratio such as 75.2 or 49.8 indicates the interaction between the nucleotide base and dye molecule. The spectra with a large positive peak at 515 mμ are, however, quite different from that of DNA-AO complex under similar conditions. (2) With an intermediate P/D ratio (26.5 to 9.6) dye molecules bound strongly to the polynucleotide chain. (3) With low P/D ratios (≤7.5) the interaction appears to be due to the stacked dye molecules in the single-stranded part of tRNA. The spectra of the third group have an isobestic point at 477 mμ. Below a P/D ratio of 4 the spectrum shows one positive and two negative bands which may be the characteristics of circular dichroism of stacked dyes in polynucleotide chain.Although no drastic change in the conformation of tRNA itself was detectable in the presence of Mg++ in the ultraviolet region, a dramatic change was observed in the circular dichroism of tRNA-acridine orange complex when Mg++ concentration was increased to 10-3M. It was inferred that certain conformational changes other than simple hydrogen bond formation occured in tRNA molecules at this high Mg++ concentration, so that the amount of bound dye in the stacking condition was increased through the transition.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110805
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    The hydrolysis of poly (L-prolyl-glycyl-L-prolyl) by bacterial collagenase (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1607-1612 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly (L-Prolyl-Glycyl-L-Prolyl), a polymer which resembles collagen by physical and immunochemical criteria, has been shown to serve as a substrate for the highly specific bacterial collagenase obtained from Clostridium histolyticum. The postulated reaction products Gly Pro, Gly Pro Pro, and Pro Gly Pro Pro have been isolated. The enzyme has been employed as an analytical tool in elucidating the sequence of synthesized polymers of proline and glycine.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110807
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Effect of non-complementary nucleotides on the rate of helix formation: Kinetics of formation of poly (I)·poly (C,I) and poly (I)·poly (C,U) complexes (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1613-1620 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Apparent second-order rate constants for complex formation between poly (I) and poly (C) and copolymers of C containing non-complementary I or U residues have been determined spectrophotometrically. The rate constants decrease as the concentration of either I or U in the C strands increases-the effect seems insensitive to the species of residue involved, when differences in the thermal stabilities of the poly (I) poly (C,I) and poly (I). poly (C,U) complexes are taken into account. These results suggest that low concentrations of relatively stable defects can alter the apparent kinetic “complexity” of polynucleotides as determined by hybridization methods (C0t analysis).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110808
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    The kinetics of the renaturation of deoxyribonucleic acid denatured in the presence of copper (II) ions (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1661-1684 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: DNA which has been heat denatured in the presence of Cu++ ions can be completely and rapidly renatured by increasing the ionic strength of the solution above a critical value. A kinetic study of this renaturation recation was carried out by following the associated UV absorbance change and also by following the change in free Cu++ ion concentration by means of a specific Cu++ ion activity electrode. The data obtained could be fitted to first-order kinetics for a considerable extent of the reaction and the rate constant was found to increase with temperature and ionic strength, but to decrease markedly as the bulk viscosity of the solution was increased. At temperatures greater than 5°C the reaction rate depended on the time elapsing between denaturation and the commencement of the renaturation reaction. As there was good agreement between the rate constants obtained by following the decrease in hyperchromism and by following the increase in free Cu++ ion concentration, it is concluded that under the conditions employed, the rate of renaturation is determined by the rate of release of Cu++ ions from the denatured DNA-Cu++ complex.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110812
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Conformational studies on copolymers of L-leusine and L-leucine: Circular dichroism and potentiometric titration studies (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1723-1744 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational aspects of a series of copolymers of L-Leucine and L-leucine [poly-(LysxLeuy)] containing 0 to 0.41 mole fraction L-leucine have been studied by circular dichroism (CD) and potentiometric titration in 0.05M KF solution. CD studies on the α-helical conformation showed a dependence of the magnitude of the CD ellipticity band at 222 nm on copolymer composition; the [θ]222 decreasing with higher leucine contents. This was interpreted as the result of an increase of the hydrophobicity of the environment of the amide group due to the presence of the leucyl residues. Values of the Zimm-Rice parameter, σ, for the copolymers were obtained from the potentiometric titrations and used to fit theoretical curves to the experimental data. Using the variation of σ with polymer composition, a value of σ for the leucyl residue was estimated to be 6.3 × 10-2, assuming independence of σ on the amino acid sequence in the copolymer. The free energy change for the conversion of one mole residue from uncharged helix to uncharged coil, ΔGhc°, was also obtained from the titration data for each copolymer up to a leucine mole fraction of 0.16; a value of 385 cal mole-1 was estimated for ΔGhc° for a leucyl residue. These values for σ and ΔGhc° are compared with other values in the literature for various amino acid residues obtained from titration and melting curve data.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110817
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    The absence of an isotope effect on the stability of the poly-β-benzyl-L-aspartate α-helix in aprotic solvents (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1745-1763 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical rotatory dispersion measurements were used to follow the transition from the helical to the random coil conformation of poly-β-benzyl-L-aspartate as induced by changes in temperature and solvent composition in mixtures of dioxane and dimethylsulfoxide. Within experimental error, there is no difference in the stability of the helical state as measured in this way for the protonated and deuterated forms of the polypeptide. This result is considered in terms of previous attempts to study the isotope effect on conformational transitions of helical biological macromolecules and polypeptides. The conclusion is drawn that the apparent changes in conformational stability observed in these previous systems arise from alteration of the properties of the solvent. Speculations are advanced regarding the contribution of the interpeptide bond to the stability of the helical state.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110818
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Conformational aspects of polypeptide structure. XLI. Crystal structure of S-thiazolidine-4-carboxylic acid and helical structure of poly[(S)-thiazolidine-4-carboxylic acid]This work was carried out at the Polytechnic Institute of Brooklyn and the Istituto Chimico, Naples, Italy. (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1779-1787 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The helical structures of poly[(S)-thiazolidine-4-carboxylic acid], in the cis and trans forms, were redetermined by using the new sets of bond angles and bond lengths established by X-ray diffraction analysis of L-thioproline. Calculations of the helical structures of poly-L-proline and poly[(S)-oxazolidine-4-carboxylic acid] were also repeated. As a result of these energy calculations, it is suggested that, in contrast to poly-L-proline and poly[(S)-oxazolidine-4-carboxylic acid], poly[(S)-thiazolidine-4-carboxylic acid] should not mutarotate from the trans to the cis form. This result is due to the fact that the energy barrier for the conversion is most likely too high. Previous experimental work is consistent with this finding.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110903
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Optical rotatory dispersion and circular dichroism of benzoyl polysaccharidesParts of this work were presented at the “Makromolekulare Kolloquium” 1969, Freiburg/Brsg., BRD. (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1997-2013 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurements of optical rotatory dispersion (ORD) and circular dichroism (CD) were made in the range of 400-205 nm for polysaccharide tribenzoates such as 2,3,6-tri-O-benzoyl amylose (I), 2,3,4-tri-O-benzoyl dextran (II), tri-O-benzoyl pullulan (III), 2,3,6-tri-O-benzoyl cellulose (IV), 2,3,6-tri-O-benzoyl mannan (V), and polyglycan dibenzoates such as 2,3,-di-O-benzoyl amylose (VI), cellulose (VII), and mannan (VIII). All compounds exhibit Cotton effects in the region of their UV absorption bands (206-285 nm).Comparison of the corresponding di- and tribenzoyl polysaccharides shows a qualitative agreement in number, position and sign of the CD bands but differences in ellipticity magnitude. The disubstituted derivatives exhibit smaller amplitudes than the trisubstituted ones. The contribution of the C(6) chromophore (linked by a CH2-group to the asymmetric C(5) atom) was determined to be of the same sign as the combined contribution of the C(2) and C(3) substituents.The CD bonds of the individual polysaccharide derivatives, which differ in number, sign, and position, were discussed in terms of the steric position of the single chromophores and the steric arrangement and interaction caused by the configuration of the polysaccharides. The optical behavior of these polysaccharide derivatives was found to be not strongly influenced by a definite chain conformation in solution.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111002
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Spectroscopic study of monosubstituted amides. II. Rotation isomers in amides substituted by aliphatic side-chain modelsFor Part I See Ref. 3. This paper is one part of F. Fillaux's thesis registered by the CNRS (France) under No. A07245. (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2063-2077 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of the substituents upon the Amide I and νNH frequencies has been analyzed for ten amides substituted by aliphatic side chains. By considering the aliphatic chain field effect, some data are obtained as to the conformation of the N—Cα bond. In two amides, the presence of an equilibrium between two conformers is shown and a semiquantitative estimation of the energies involved is obtained. The consequences for polypeptides conformation, especially for poly-L-valine, are discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111007
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Viscosity of heparin as a function of dielectric constant and of desulfation (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2079-2090 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of dielectric constant (D) of the solvent on the viscosity of heparin was examined using the relation \documentclass{article}\pagestyle{empty}\begin{document}$ \eta _{{\rm sp}} /c = [\eta ]_\infty (1 + k/\sqrt c) $\end{document}, where [η]∞ is the shielded intrinsic viscosity obtained by extrapolating \documentclass{article}\pagestyle{empty}\begin{document}$ \eta _{{\rm sp}} /c\,{\rm vs}{\rm . }\,1/\sqrt c ) $\end{document} to infinite concentration, and k is an interaction parameter independent of the dielectric constant of the solvent. This equation was previously reported by the authors9 for describing the reduced viscosities of strong polyelectrolytes in salt-free polar solvents. It was found that the [η]∞ of heparin increases linearly with increasing dielectric constant of the solvent whereas the k values were, within experimental error, independent of D in the range 54.7 〈 D 〈 93.2 examined. Graded hydrolysis of heparin from its acid form (heparinic acid) at 57°C resulted in samples of varying degree of desulfation with corresponding decrease in biological activity. It was found that both [η]∞ and k decrease with increasing desulfation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111008
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    New banding species, with densities of phage-ghost clusters, produced from lambda phage particles on storage (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2171-2177 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Density gradient analysis of purified lambda phage particles after storage reveals that minor species with new banding desities arise during storage. These have densities expected for phage-ghost clusters containing integra rations of ghosts to phage particles. A lage numbersof new banding species has been observed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111016
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Synthetic peptides related to the entire sequence of yeast iso-1-cytochrome C (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2191-2194 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111019
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    A comparative X-ray study of a nucleoprotamine and DNA complexes with polylysine and polyarginine (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2223-2231 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The high-humidity X-ray pattern of oriented fibers prepared from salmon spermheads strongly resembles that of DNA in the B form. However, the nucleoprotamine pattern has a more intense first layer line and increased lateral unit-cell dimensions.Complexes of DNA with poly-L-lysine and poly-L-arginine were prepared and photographed at various relative humidities. The most crystalline patterns were obtained at 92% and also indicate DNA in the B form. However, whereas polylysine-DNA, like the spermheads, has a primitive hexagonal cell, polyarginine-DNA, like NaDNA, has three molecules in the unit cell. Polylysine-DNA, but not polyarginine-DNA, also resembles spermheads in having a strong first layer line.All three complexes show increasing intermolecular distance with increasing humidity, but with sharp maxima when photographed in water, which indicates cross-linking between the molecules. Lowering the humidity causes the polylysine-DNA, but not polyarginine-DNA, to change conformation from the B to the C form.The structural implications of these results are discussed in the light of model-building studies and a comparison of calculated and observed X-ray intensities.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    The pH dependence of tyrosine cyanuration in proteins (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2233-2240 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pH, temperature, and reagent concentration dependences of the cyanuration of tyrosines within proteins are compared with those of the free amino acid. The results indicate that the mechanism of the cyanuration reaction is a nucleophilic aromatic substitution of the SN2 type, where the tyrosine oxygen acts as a nucleophile and the displacement takes places at a carbon atom which is part of the six-membered ring of the s-triazene. This reaction must compete with the hydrolysis of cyanuric fluoride in aqueous media. These competing reactions generate curves for the pH dependence of the reactivity of tyrosine with cyanuric fluoride whihc vary in a predictable manner with the extent of ionization of tyrosine and the concentration of cyanuric fluoride. In the case of proteins, the dependence of the degree of tyrosine reactivity on pH and temperature within the pH range of full reactivity of the free amino acid reflects constraints imposed by the microenvironment of these groups within the three-dimensional structure of the macromolecule.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111104
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Salt bonding in proteins. A model for the abnormal hydrogen ion titration and the strong anion binding of serum albumin (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2197-2221 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Serum albumin undergoes a conformational change at pH 4, known as the N-F transition. In the customary Linderstrøm-Lang treatment of hydrogen ion titration, the carboxyl groups in serum albumin either have an abnormally low pK, or are buried in charged form, and the Linderstrøm-Lang charging parameter ω decreases dramatically at the N-F isomerization. In the present paper partition functions are derived and distribution functions are calculated for a model permitting salt bonding between the positively and negatively charged sites on a macromolecule. The N-form has an abnormally high salt bonding constant whereas that of the F-form corresponds to that of small ions. The result obtained is consistent with a “normal” intrinsic pK of the carboxyl groups of serum albumin without burying of any charges and with an unchanged ω. The nature of the postulated salt bonding is discussed.Further, it is shown that the “abnormal salt bonding” of serum albumin can explain its unusual ability to bind anions. Theoretical binding curves are calculated and compared with literature data of the Cl- binding of serum albumin. The relation of the present model to other models of hydrogen ion and anion binding to proteins is discussed. Some additional consequences of the present model are pointed out; a transition in the alkaline range, analogous to the acid transition, seems probable. Literature data support the existence of such a transition but do not allow detailed calculations at present.A general, thermodynamic treatment of the interactions between small ligands and macromolecules is outlined. Important points are the choice of the statistical-me- chanical ensemble and considerations of the fluctuations about the mean bonding, if (i) there are not only a ligand-locus interaction but also interligand interactions (in par- ticular intdigand attraction), or (ii) there is a conformational change in themacromole- cule depending on the ligand binding. In these cases, the binding isotherms obtained from thermodynamically closed systems (canonical ensemble) may erroneously indicate a distribution about a single probability maximum, i.e., the statistical mean binding N̄, and fluctuations about this value. The description of a phase change in a bound phase or a change in the “internal” self-interactions of a macromolecule requires a bind- ing equation permitting distributions about two maxima, i.e., (i) N1* 〈 N̄ (“thin” phase) and N2* 〉 N̄ (“condensed” phase) or (ii) two macromolecular conformations P′, and P″, having occupancy numbers N̄, and N̄2, respectively. The N-F transition is an example illustrating the relation between the complete distribution functions and the two-state approximation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    The β-conformation and association of low-molecular-weight poly-γ-benzyl-L-glutamate in Solutions (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 493-507 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three samples of poly-γ-benzyl-L-glutamate have been prepared from γ-benzyl-N-carboxy-L-glutamate anhydride with n-hexylamine initiation at anhydride-to-initiator molar ratios, [A]/[I], of 3, 4, and 8, and their conformation and association in ethylene dichloride and dioxane have been investigated by means of infrared spectra and vapor-pressure osmometry. Two conformations, σ-and β-forms, are present in those solvents, and the content of β-form increases with increasing A/I value and concentration. At infinite dilution molecular association is absent, but the number-average molecular weight increases with cocentration, markedly in ethylene dichloride and, to a lesser extent, in dioxane. The fraction of residues involved in associated molecules have been estimated as a function of concentration. Combination of the content of β-structure with the fraction of association leads to the following results. The A/I 3 and 4 polymers form intermolecularly hydrogen-bonded aggregates, in which hydrogen-bonded residues are in the β-structure. The A/I 8 polymer has the intramolecularly hydrogen-bonded β-structure at very low concentrations, but it also forms intermolecularly hydrogen-bonded aggregates at high concentrations.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110214
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Perspectives report: Melting of DNA. Its study and application as a research method (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 527-528 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110218
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Dielectric dispersion of the α-helix at the transition region to random coil (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 587-605 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dielectric studies have been carried out for the helix-coil transition of poly-β-benzyl-L-aspartate with m-cresol as a solvent. The transition of the solute molecules has been sharply reflected as a characteristic change in the dielectric dispersion curves in changing temperature. Two polarizations, one having a low and the other a high critical frequency, have appeared. According to theoretical considerations of a model of a broken helix, the former is found to come from the orientation. of helical sequences and the latter from the chemical relaxation due to the helix-coil transition. It also seems likely that the unfolded chain may have a polarizability which could not be neglected at the high-temperature side of the transition.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110305
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Conformational studies on polypeptides. The effect of sodium perchlorate on the conformation of poly-L-lysine and of random copolymers of L-lysine and L-phenylalanine in aqueous solution (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 633-643 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Circular Dichroism measurements have been carried out on poly-L-lysine (PLL) and on random copolymers of lysine and phenylalanine at various pH values and in the presence of different amounts of NaClO4. The results indicate that either the homopolymer or the copolymers at pH conditions at which the side-chain amino groups are fully protonated, assume the right-handed α-helical conformation in the presence of NaClO4. The results are interpreted in terms of specific binding of ClO4- ions on charged side-chain amino groups.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110308
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Pressure dependence of the helix-coil transition temperature for polynucleic acid helices (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 667-678 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal denaturation of DNA's and the corresponding helix-coil transformation of artificial polyribonucleic and polydeoxyribonucleic acids have been studied extensively both theoretically1-13 and experimentally. 14-30 Much less work has been carried out on the properties of these polynucleic acids at high pressure, and in particular, on the presure dependence of the helix-coil transition temperature.31-33 Light-scattering techniques have been used in this study to measure the pressure dependence of the helix-coil transition temperature of the two- and three-stranded helices of polyriboadenylic and polyribouridilic acids and of calf thymus DNA. From the slopes of the transition temperature vs. pressure curves and heats of transition obtained from the literature,20,34 the following volume changes from these helix-coil transitions have been obtained: (a) -0.96 cc/mole of nucleotide base pairs for the poly (A + U) transition, (b) +0.35 cc/mole of nucleotide base trios for the poly (A + 2U) transition, and (c) +2.7 cc/mole of nucleotide base pairs for the DNA transition. The relative magnitudes and signs of these volume changes which show that poly (A + U) is destabilized by increased pressure, whereas poly (A + 2U) and calf thymus DNA are stabilized by increased pressure, indicates that further development of the helix-coil transition theory for polynucleotides is needed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110312
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    The molecular weight of a fast sedimenting MS2 RNA form (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 735-735 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110319
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    The helix-coil transitions of poly (dA). Poly (dT) and poly (dA-dT). Poly (dA-dT) (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 745-759 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Helix-coil transition curves are calculated for poly (dA) poly(dT) and poly (dA-dT) poly (dA-dT) using the integral equation approach of Goel and Montroll.5 The transitions are described by the loop entropy model with the exponent of the loop entropy factor, k, remaining an arbitrary constant. The theoretical calculations are compared with experimental transition curves of the two polymers. Results indicate that the stacking energies for these two polymers differ by about 1 kcal/mole of base pairs. Also, a fit between theory and experiment was not possible for k 〉 1.70.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    The ultraviolet circular dichroism of some natural DNAs and an analysis of the spectra for sequence information (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 853-879 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism spectra of many natural DNAs and double-stranded synthetic polynucleotides were obtained. The eight first-neighbor contributions to the CD spectra of a DNA have been extracted from these data. Therefore, the CD spectrum for any DNA with known first-neighbor frequencies may be easily calculated. For a natural DNA the CD spectrum may be approximated by assuming the first-neighbor frequencies have the most probable values consistent with the base composition. Under favorable conditions, the measured CD spectrum can be used to determine thirteen of the sixteen first-neighbor frequencies of a DNA to ± 0.02 mole percent. The TG, CA, and TA first-neighbor cannot be unambiguously resolved by our method. The accuracy of the first-neighbor frequency analysis depends on the number of different first-neighbors present in the DNA and the extent to which they differ from the most probable value.The extinction coefficient at 260 nm and the base composition can also be calculated from the CD spectrum.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Masthead (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Theory of protein secondary structure and algorithm of its prediction (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 15-25 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A molecular theory of protein secondary structure is presented that takes account of both local interactions inside each chain region and long-range interactions between different regions, incorporating all these interactions in a single Ising-like model. Local interactions are evaluated from the stereochemical theory describing the relative stabilities of α- and β-structures for different residues in synthetic polypeptides, while long-range effects are approximated by the interaction of each chain region with the averaged hydrophobic template. Based on this theory, an algorithm of protein secondary structure prediction is proposed and examples are given of “blind” predictions made before the x-ray structural data became available.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Monte carlo simulations of peptide solvation (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 27-31 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: To increase our understanding of peptide-water interactions, we are simulating the behavior of water molecules in the intermolecular channels of [Phe4Val6]antamanide dododecahydrate crystals. There is good overall agreement between the positions predicted using two alternative potential functions and those that have been observed by x-ray diffraction. Detailed differences between the predictions for the two potential functions are discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    An empirical approach to protein conformation stability and flexibility (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 49-58 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Experimental measurements of disulfide bond stability at various stages of protein folding are considered in terms of the effective concentrations of the thiol groups relative to each other; values of up to 107M are observed, so that intramolecular interactions within the interior of a protein are much more stable, and provide greater stability to the folded conformation, than those on the surface or in a flexible segment. Intramolecular interactions can have substantially lower free energies than intermolecular, for solely entropic reasons; this implies that polar interactions, such as hydrogen bonds and salt bridges, can provide net stabilization to a folded conformation, in spite of the unfolded protein having intermolecular interactions with the solvent. These considerations can account for the lower free energy and enthalpy of the folded state and are useful for considering protein flexibility.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220110
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Conformational properties of microtubule protein: Their relation to the self-assembly process in vitro (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 87-91 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Near- and far-uv CD spectra of microtubule protein preparations have been examined to study the possible role of protein conformation in relation to the kinetics of the self-assembly of these proteins into microtubules in vitro. Although tubulin can form conformations with high helical content under apolar solution conditions, this transformation is apparently not involved in self-assembly. There is no major perturbation of tubulin near-uv CD by reagents and solution conditions favoring assembly. Thus, in these preparations, tubulin, as dimer and as oligomer with MAPs, is effectively in the conformation in which it undergoes self-assembly. This conclusion is consistent with a hybrid model of assembly of microtubule protein involving direct incorporation of oligomeric species as an alternative to the condensation polymerization of tubulin dimer as the exclusive assembly mechanism.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220114
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    The unfolding mechanism of thermolysin (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 101-105 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ligand-modulated kinetics of the autoproteolysis of thermolysin and the high-molecular-weight products of the reaction provide evidence for the conclusion that separation of the two structural domains is most probably the first step on the unfolding pathway of the protein under native conditions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220116
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Genetic and biochemical analysis of in vivo protein folding and subunit assembly (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 125-129 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The in vivo pathway of folding and subunit assembly of a trimeric bacteriophage protein has been studied by characterizing precursors to the native protein and by analyzing temperature-sensitive mutations that kinetically block the pathway. The native trimer is formed via an intermediate composed of three partially folded chains, the protrimer. At 39°C, temperature-sensitive mutations prevent the formation of both the native trimer and the protrimer, possibly by destabilizing earlier intermediates. However, the mutations do not affect the stability of the native protein, formed at 30°C. Thus, these mutations identify amino acid residues involved in interactions that determine the folding pathway.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220120
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Conformational and functional properties of hemoglobin in perturbed solvent: Kinetics of O2 release (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 1677-1696 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We studied the kinetics of O2 release by oxyhemoglobin caused by sodium dithionite, in the presence and in the absence of organic cosolvents (monohydric alcohols and formamide) at 10°C. This study was performed by using standard stopped-flow techniques coupled with microprocessor-based data acquisition. We have fitted the experimental data to a mathematical expression obtained on the basis of a two-state model that takes into account the kinetic heterogeneity between α- and β-chains and the presence of αβ-dimers in oxyhemoglobin solutions. Results indicate that the cosolvents mainly affect the allosteric parameter L, i.e., the T ⇄ R conformational equilibrium of hemoglobin, leaving the intrinsic deoxygenation rates of both R and T states almost unaltered. The L values obtained in the present work are in excellent agreement with analogous values previously estimated from oxygen equilibrium measurements.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220706
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Solution properties of porcine submaxillary mucin (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 1657-1675 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Porcine submaxillary mucin (PSM) is a glycoprotein composed of a protein core and frequent, short oligosaccharide side chains. We report static and dynamic light scattering experiments and intrinsic viscosities for PSM in aqueous solvent systems. In 0.1M NaCl solution, the data suggest PSM exists as large, internally branched, highly hydrated, polydisperse aggregates that slowly dissociate to give a stable species of weight-average molecular weight (Mw) 7.4 × 106. In 6M GdnHCl solution, the noncovalent bonds between PSM molecules are broken, giving a highly elongated molecule of Mw = 2.0 × 106. The irreversible nature of this dissociation suggests that the forces that stabilize the native aggregates of PSM in 0.1M NaCl are specific in nature. On reduction of PSM with mercaptoethanol, the polydispersity decreases and Mw also decreases to 9 × 105. A discrete change is observed in the solution properties of PSM in 0.1M NaCl at a concentration of 2mg/mL, manifested by a sudden decrease in the translational diffusion coefficient, an increase in viscosity number, and a decrease in slope of the osmotic compressibility. We tentatively propose that a weak and reversible secondary association process occurs at this concentration, although a purely hydrodynamic interaction cannot be ruled out.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220705
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Linear dichroism studies of nucleic acids. III. Reduced dichoism curves of DNA in ethanol-water and in poly(vinyl alcohol) filmsFor Part II in this series, see Matsuoka, Y. & Nordén, B. (1982) Biopolymers 21, 2433-2452. (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 1731-1746 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The uv linear dichroism of calf thylus DNA has been studied at different degrees of orientation both in flow-oriented ethanol-water solutions and in a stretched aqueous host of poly(vinyl alcohol) (PVA). The reduced dichroism (LDR) curves in the region 250-290 nm for DNA in PVA films at 75 and 100% relative humidity (r.h.) are in fair agreement with the curves calculated for the A- and B-forms of DNA, based on the fiber structures and the π-π* transitions of the free bases. This suggests that DNA adopts its A and B conformations in PVA at 75 and 100% r.h. In ethanol, on the other hand, a deviation from the A-form spectrum shows that the conformation of DNA in the solution can differ from the fiber structure. At shorter wavelenghts, a positive contribution to LDR is explained in terms of an out-of-plane polarized n-π* transition.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220709
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Localized vibrational modes at a double-helix-single-strand junction (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 1759-1767 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A vibrational analysis has been performed for a double-helix-single-strand junction. A Green's function technique has been used in treating the junction as a defect on an otherwise perfect system of infinite chain homopolymers. We calculate that the hydrogen-bond stretching at the junction is amplified by a factor of two relative to the interior of the double helix, B poly(dG)-poly(dC). Breathing modes localized near the junction have also been predicted at 77 and 94 wave numbers. The calculated results are shown to be consistent with predictions from recent nmr studies.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220711
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Masthead (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220801
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Nmr studies of a free and protected tetrapeptide glycyl-L-prolylglycylglycine in β-turn-supporting environment (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 1853-1868 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nmr studies of the protected and free tetrapeptide Gly-Pro-Gly-Gly were carried out in β-turn-supporting solvents, that is, in CDCl3 for Z-Gly-Pro-Gly-Gly-OMe and in Me2SO-d6 for H-Gly-Pro-Gly-Gly-OH. Comparisons with specifically α-deuterated analogs gave complete assignments of the NH and methylene regions. Analysis of chemical shifts, coupling constants, and the temperature dependence of chemical shifts show that the peptide adopts a type II β-turn conformation. This turn is stabilized for the protected tetrapeptide by two hydrogen bonds between (i) C=O (Gly1) and NH(Gly4), and (ii) urethane function NH and methyl ester C=O.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220804
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Computer simulation of the conformational properties of retro-inverso peptides. II. Ab initio study, spatial electron distribution, and population analysis of N-formylglycine methylamide, N-formyl N′-acetyldiaminomethane, and N-methylmalonamide (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 1901-1917 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio minimal and split-valence basis set calculations have been performed on compounds that are involved in retro-inverso modifications, i.e., gem-diaminoalkyl and malonyl structures. These calculations are compared with empirical force field calculations and the minor differences discussed. All calculations agree that the preferred helical conformation of the isolated gem-diaminoalkyl and malonyl derivatives of residues found in the retro-inverso modified peptides is 5-8 kcal/mol lower than the Ceq7 conformation preferred by the isolated peptide residues. Population analysis and contour plots of the charge distribution are used to help explain the differences between the model compounds.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220807
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Masthead (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220901
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Masthead (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220601
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Lysinium, argininum, glutamate, and aspartate ions in water solution (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 1449-1460 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: SCF-LCAO-MO ab initio calculations were carried out for the interaction between a charged amino acid and a water molecule. The results obtained were fitted by an analytical potential function of the atom-atom type, and the corresponding potential surfaces were examined by means of orientationally optimized isoenergy contour maps. Monte Carlo simulations were also carried out on a few selected solute-water clusters at T = 300 K, in order to obtain insight into the solvation structure.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220603
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Improved technique for calculating X-ray scattering intensity of biopolymers in solution: Evaluation of the form, volume, and surface of a particle (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 1507-1522 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An improved cube method has been developed for calculating the intensity of diffuse x-ray scattering of macromolecules in solution using a certain set of their atomic coordinates. The technique is based on the ideas of B. Lee and F. M. Richards [(1971) J. Mol. Biol. 55, 374-400] and Richards [(1977) Annu. Rev. Biophys. Bioeng. 6, 151-176] on the possibility of estimating the molecular and accessible surface of a particle by “rolling” a sphere, simulating a water molecule, on its molecular surface. It is shown that this technique is more advantageous than earlier versions of the cube methods. The improved technique for calculating scattering curves was utilized for several globular proteins, and for the first time, reliable scattering curves were obtained for protein-“bound” water complexes. In the case of globular proteins and tRNA, this technique has permitted a strict evaluation of their accessible surfaces, their volumes, and, apparently for the first time, their complete molecular surfaces.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220607
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Masthead (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220701
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Viscometric study of the proteoglycan-hyaluronate (2:1) “dimer”: Minimum hyaluronate chain length (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2501-2506 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Extended retro-inverso analogs of somatostatin (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2523-2538 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An extended retro-inverso modification was introduced at the central six residues of the somatostatin molecule, the region of internal enzymatic degradations. The synthesis of the analog [Ala4,g-Phe6-r-D-Phe7-r-D-Trp8-r-D-Lys9-r-D-Thr10-m-R,S-Phe11]-somatostatin required a unique strategy accommodating the unusual structure. Side-chain protection based on the t-butyl group in combination with Fmoc and Nps α-amino protection was employed. The key component containing the gem-diaminoalkyl residue was generated by an iodobenzene bistrifluoroacetate-mediated reaction. The separation of diastereomers of the cyclic tetradecapeptide in highly pure form was accomplished by high-performance liguid chromatography on a semipreparative scale. The analogs exhibited very low potency in the growth hormone inhibition test in vitro. This is interpreted as the consequence of the complex structural changes created by the extended retro-inverso modification.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    A critical evaluation of models for complex molecular dynamics: Application to NMR studies of double- and single-stranded DNA (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2703-2726 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nature of internal and overall motions in native (double-stranded) and denatured (single-stranded) DNA fragments 120-160 base pairs (bp) long is examined by molecular-dynamics modeling using 13C-nmr spin-relaxation data obtained over the frequency range of 37-125 MHz. The broad range of 13C frequencies is required to differentiate among various models. Relatively narrow linewidths, large nuclear Overhauser enhancements (NOEs), and short T1 values all vary significantly with frequency and indicate the presence of rapid, restricted internal motions on the nanosecond time scale. For double-stranded DNA monomer fragments (147 bp, 24 Å diam at 32°C), the overall motion is that of an axially symmetric cylinder (τx = ∼10-6 s;τZ = ∼1.8 × 10-8s), which is in good agreement with values calculated from hydrodynamic theory (τx = ∼1.8 × 10-6 s; τZ = ∼2.7 × 10-8 s). The DNA internal motion can be modeled as restricted amplitude internal diffusion of individual C—H vectors of deoxyribose methine carbons C1′, C3′, and C4′, either with conic boundary conditions (τw = ∼4 × 10-9 s, θcone = ∼21°) or as a bistable jump (τA = τB = ∼2 × 10-9 s, θ = ∼15°). We discuss the critical role in molecular-dynamics modeling played by the angle (β) that individual C—H vectors make with the long axis of the DNA helix. Heat denaturation brings about increases in both the rate and amplitude of the internal motion (described by the wobble model with τW = ∼0.2 × 10-9 s, θcone = ∼50°), and overall motion is affected by becoming essentially isotropic (τx = τZ = ∼5 × 10-8 s) for the single-stranded molecules. Since 13C-nmr data obtained at various DNA concentrations for C2′ of the deoxyribose ring is not described well by the above models, a new model incorporating an additional internal motion is proposed to take into account the rapid, extensive, and weakly coupled motion of C2′.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221214
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Kinetic studies of the interaction of methyl orange with poly(L-lysine) by stopped-flow with circular dichroism detection (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2035-2044 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction of methyl orange with poly(L-lysine) was studied kinetically by the stopped-flow technique with CD detection, as well as by static CD titration experiments. In the static experiments, the differences observed in the polymer-to-dye ratio dependences of the CD spectra and absorption spectra suggested at least two kinds of bound states of the methyl orange attached to the polymer. The kinetic experiments using the stopped-flow apparatus, however, revealed four distinct reaction processes. The reaction mechanism was elucidated from the concentration dependence of the time constant for each process as follows: the first process was attributed to the bimolecular binding step of methyl orange to the side chain of poly(L-lysine), the second and third process were ascribed to the intramolecular reaction of the polymer-dye complex, and the fourth process was found to be the intermolecular aggregation of the polymer-dye complex. The origin of the stacking of methyl orange on poly(L-lysine) is discussed on the basis of the characteristics of signal amplitudes obtained from the kinetic experiments for these processes.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220904
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Comparative study of GuHCl denaturation of globular proteins. I. Spectroscopic and chromatographic analysis of the denaturation curves of ribonuclease A, cytochrome c, and pepsinogen (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2105-2122 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel devices for the spectroscopic and chromatographic analysis of the denaturation curves of the protein are described. A multidimensional spectroscopic measuring system makes it possible to carry out simultaneous and continuous acquisition of a set of data of different spectroscopic dimensions at several wavelengths in the course of increasing or decreasing denaturational perturbation. GuHCl-gradient chromatography can provide information about the progressive change of the protein volume in the course of increasing GuHCl concentration. Thus, denaturation curves with a high data-point density can be obtained. The data-storing function by a magnetic disk memory provides enough precision for a rigorous investigation of the correlation among the curves that probe different aspects of denaturation. The GuHCl denaturation of RNase A, cytochrome c, and pepsinogen are studied to demonstrate the high performance of these devices. Three types of transitions are found in these three proteins and the multiphasic nature of the transitions is clearly detected in the last two proteins.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360220909
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Masthead (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221001
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Quantitative relationship between the surface charge density and dynamic charge of linear polyelectrolytes in the low charge-density limit (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2169-2172 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221004
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Boundaries of the universal K3 region and plateau region of the dynamic structure factor for DNA (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2207-2217 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A sufficiently long semiflexible filamentous macromolecule is theroretically expected to exhibit three different domains of behavior of its apparent diffusion coefficient Dapp(K) as a function of scattering vector K: (1) the small wave vector limit, where Dapp(K) = D0 is the translational diffusion coefficient of the center-of-mass; (2) the universal K3 region, where Dapp(K) = (kBT/6πη)K is a universal function of K independent of any property of the molecule itself; (c) the plateau region at large K2, where Dapp(K) approaches either a plateau, or gradually sloping quasiplateau, characteristic of local (elastic) rigid-body motions of the filament. The existence of each of these different domains has now been established experimentally for at least some polymers. The boundaries of the universal K3 region and the plateau region are determined theoretically here using precise quantitative criteria for universal or plateau behavior of Dapp(K) for a Rouse-Zimm model containing N + 1 subchains with rms subchain extension b. Allowing a maximum of 13% nonuniversal behavior, the domain of the universal K3 region is given by K2R2G = K2Nb2/6 ≥ 7 and K2b2 ≤ 0.54. Allowing as much as 10% nonplateau behavior, the boundary for onset of plateau behavior is K2b2 = 18.3. Dapp(K) is at least 50% nonuniversal when K2b2/6 = 6 ln 3. Extension of these results to DNA is examined theoretically, and good agreement of the pertinent predictions with published experimental data is demonstrated.It is concluded that no truly universal K3 region exists for DNA with Mr ≤ 107 and persistence length a ≥ 450 Å, although marginally (≤17% nonuniversal) universal behavior, is exhibited in a very narrow domain 0.64 × 1010 ≤ K2 ≤ 0.84 × 1010 cm-2 for φ29 DNA (Mr = 11.5 × 106). More than 50% of Dapp(K) is governed by local (elastic) rigid-body motions when K2 = 5.23 × 1010 cm-2. The existence of a very wide region of nonuniversal apparent K3 behavior extending up to very large K2, far into the plateau region, is demonstrated in a plot of Dapp(K)/K vs K2 for the Rouse-Zimm model. This is shown to stem in part from visual artifacts of plotting Dapp(K)/K vs K2, even for rigid species.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221007
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Masthead (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Orientational interactions in low-concentration DNA solutions (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2353-2366 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rotational relaxation tiem τ3 of DNA molecules (Mw ≃ 5 × 106) in solution has been determined by the transient electric birefringence method. The analysis of the birefringence decay makes it possible to study only the higher-molecular-weight fraction, the molecules being considered as rigid elongated particles in a short time scale. A marked concentration dependence of the relaxation time has been observed for DNA in low ionic strengths. Above a critical concentration c*, τ3 increases with the DNA concentration, c. The value of c* increases with the ionic strength. For 10-3 ionic strength (with NaCl), c* is about 10 μg/mL; then we observe the same strong concentration dependence of rotational relaxation times as recently reported for rodlike M-13 viruses [Maguire, J. F., McTague, J. P. & Rondelez, F. (1980) Phys. Rev. Lett. 45, 1891-1894]. These results may be discussed in terms of the Doi-Edwards theory for rotational relaxation time of rigid macromolecules [Doi, M. (1975) J. Phys. 36, 607-611; Doi, M. & Edwards, S. F. (1978) J. Chem. Soc. Faraday Trans. 74, 918-932] and the critical concentration above which the interactions between the molecules begin to appear allows determining the corresponding molecular length. We observe a very good agreement between the DNA lengths obtained from the c* values and by using the infinite dilution value of τ3 and Broersma's equation. Therefore, only highly diluted solutions can be used if intrinsic molecular properties based on the rotational diffusion of high-molecular-weight elongated molecules are studied.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221104
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Heat capacity increments: Conformational transitions in polypeptides (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2411-2421 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A thermodynamic treatment of the helix-coil transition of synthetic polypeptides in binary organic solvent mixtures is extended to describe isobaric heat-capacity increments associated with the phenomenon. This development resolves such increments into three components: two associated respectively with intrinsic differences between the ordered and disordered states of the macromolecule and between the coil-solvent complex and its components, and a third term derived from the temperature dependence in the fraction of coil residues bound to active solvent. Insights derived from this analysis are also applied to the discussion of some heat capacity increments associated with the denaturation of globular proteins.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Masthead (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Laser-Raman spectra, sulfhydryl groups, and conformation of the cystine linkages of β-lactoglobulin (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2507-2511 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    X-Ray diffraction studies on the structure of hydrated collagen (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2539-2547 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The temperature dependence of the humidity-sensitive spacing, d, related to the lateral packing of collagen molecules was measured for fully hydrated collagen. In the vicinity of 0°C, a sudden change in d was observed, which was reversible with temperature. In the diffraction profile, below 0°C, a set of diffraction peaks identified with the hexagonal crystalline form of ice was observed. With the reduction in water content, the intensity of the set of diffraction peaks decreased and was found to be zero at a water content of 0.38 g/g collagen. These results were considered to be caused by the frozen water in collagen fibril below 0°C. According to the water content dependence of d, it was considered that up to a certain water content water absorbed would be stowed in the intermolecular space of collagen and above that water content water molecules would aggregate to make pools, i. e., extrafibrillar spaces. The unfreezable bound water was considered to be located in the intermolecular space of collagen. Size of the extrafibrillar space, determined from the intensity analysis of a smallangle x-ray scattering pattern, corroborates the speculation that the water showed in the extrafibrillar space is freezable and free. The formation of the hexagonal crystalline form of ice in the extrafibrillar space was considered to cause the sudden change in d at 0°C.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221208
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Folding type-specific secondary structure propensities of amino acids, derived from α-helical, β-sheet, α/β, and α+β proteins of known structures (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 35-49 
    Details
    ISSN: 0006-3525
    Keywords: folding type-specific secondary structure propensities ; amino acids ; α-helical proteins ; β sheet proteins ; α/β proteins ; α+β proteins ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Folding type-specific secondary structure propensities of 20 naturally occurring amino acids have been derived from α-helical, β-sheet, α/β, and α+β proteins of known structures. These data show that each residue type of amino acids has intrinsic propensities in different regions of secondary structures for different folding types of proteins. Each of the folding types shows markedly different rank ordering, indicating folding type-specific effects on the secondary structure propensities of amino acids. Rigorous statistical tests have been made to validate the folding type-specific effects. It should be noted that α and β proteins have relatively small α-helices and β-strands forming propensities respectively compared with those of α+β and α/β proteins. This may suggest that, with more complex architectures than α and β proteins, α+β and α/β proteins require larger propensities to distinguish from interacting α-helices and β-strands. Our finding of folding type-specific secondary structure propensities suggests that sequence space accessible to each folding type may have differing features. Differing sequence space features might be constrained by topological requirement for each of the folding types. Almost all strong β-sheet forming residues are hydrophobic in character regardless of folding types, thus suggesting the hydrophobicities of side chains as a key determinant of β-sheet structures. In contrast, conformational entropy of side chains is a major determinant of the helical propensities of amino acids, although other interactions such as hydrophobicities and charged interactions cannot be neglected. These results will be helpful to protein design, class-based secondary structure prediction, and protein folding. © 1998 John Wiley & Sons, Inc. Biopoly 45: 35-49, 1998
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 76
    Electronic Resource
    Electronic Resource
    Torsional control of double-stranded DNA branch migration (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 69-83 
    Details
    ISSN: 0006-3525
    Keywords: DNA branched junctions ; branch migration ; superhelical torque ; control of DNA structure ; endonuclease VII ; nanomechanical device ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: DNA branched junctions are analogues of Holliday junction recombination intermediates. Partially mobile junctions contain a limited amount of homology flanking the branch point. A partially mobile DNA branched junction has been incorporated into a synthetic double-stranded circular DNA molecule. The junction is flanked by four homologous nucleotide pairs, so that there are five possible locations for the branch point. Two opposite arms of the branched junction are joined to form the circular molecule, which contains 262 nucleotides to the base of the junction. This molecule represents a system whereby torque applied to the circular molecule can have an impact on the junction, by relocating its branch point. Ligation of the molecule produces two topoisomers; about 87% of the product is a relaxed molecule, and the rest is a molecule with one positive supercoil. The position of the branch point is assayed by cleaving the molecule with endonuclease VII. We find that the major site of the branch point in the relaxed topoisomer is at the maximally extruded position in the relaxed molecule. Upon the addition of ethidium, the major site of the branch point migrates to the minimally extruded position. © 1998 John Wiley & Sons, Inc. Biopoly 45: 69-83, 1998
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 77
    Electronic Resource
    Electronic Resource
    Conformational change and aggregation of κ-carrageenan studied by flow field-flow fractionation and multiangle light scattering (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 85-96 
    Details
    ISSN: 0006-3525
    Keywords: conformation ; aggregation ; κ-carrageenan ; flow field-flow fractionation ; multiangle light scattering ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The relatively novel combination of flow field-flow fractionation (FFF) and multiangle light scattering (MALS) was employed to study a nondegraded κ-carrageenan in different 0.1M salt solutions. The applicability of the technique was tested, and the effects of salt type and salt composition on the molar mass and radius of gyration were studied. A conformational ordering was induced at room temperature by switching the solvent from 0.1M NaCl (coil form) to 0.1M NaI (helix form). An approximate doubling of the average molar mass and an increase in radius of gyration was then observed, in agreement with results obtained previously using size exclusion chromatography-MALS. This increase in size was attributed to conformational ordering and to the formation of double helices. Severe aggregation was observed above 40% CsI in the 0.1M mixed salt solution of CsI and NaI. This was ascribed to the association of helices into large aggregates. For these large associates, having molar masses of several millions, a reversal of the elution order in flow FFF was detected. © 1998 John Wiley & Sons, Inc. Biopoly 45: 85-96 1998
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 78
    Electronic Resource
    Electronic Resource
    Calculations on the low energy conformers of N-acetyl-D-alanyl-D-alanine (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 119-133 
    Details
    ISSN: 0006-3525
    Keywords: conformations of D-alanyl-D-alanine ; β-lactam ; structural overlay ; AMBER force field ; AM1 ; ab initio ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this article a conformational analysis of the D-alanyl-D-alanine dipeptide, both charged and neutral, has been carried out. The preferred conformations were determined by means of ab initio and semiempirical quantum, together with empirical force field calculations. The AMBER* force field and the 6-31 + G** and 6-31G** ab initio levels give rise to a coincident minimum energy structure, which, on the other hand, differs from that determined by AM1, 3-21 + G, and 3-21G. The solvent effect on the different charged and neutral conformations have been considered through the AMSOL semiempirical method. A quantification regarding the structural similarities between the different dipeptide conformations and the ampicillin has been performed. The results show that the best overlay is attained by the minimum structure energy obtained by using the 6-31 + G** methodology, which presents a planar amidic nitrogen. © 1998 John Wiley & Sons, Inc. Biopoly 45: 119-133, 1998
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 79
    Electronic Resource
    Electronic Resource
    C6-oxidized cellulose: Ion interactions with mono- and divalent cations (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 157-163 
    Details
    ISSN: 0006-3525
    Keywords: chemical oxidation ; cellulose ; conformational transition ; capillary viscosity ; microcalorimetry ; calcium ions ; gels ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational behavior of different molecular weight fractions of a synthetic C6-oxidized derivative of cellulose were investigated by means of capillary viscometry, CD, and microcalorimetric measurements. Experiments were carried out in the presence of either monovalent or divalent counterions.The experimental data indicated that C6-oxidized cellulose can assume an ordered extended conformation at low ionic strength, induced by the intrachain repulsions of negative charges. This conformation was suggested to be very similar to the fully extended structure of cellulose. In addition to this, upon increasing the ionic strength, a conformational transition of the order-to-disorder type occurred. In fact, the screening of the electrostatic repulsions introduced a number of conformational kinks into the cellulosic backbone, which enabled the polymer to assume a more coiled conformation hence producing less viscous aqueous solutions. © 1998 John Wiley & Sons, Inc. Biopoly 45: 157-163, 1998
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 80
    Electronic Resource
    Electronic Resource
    Conformational stability of biological polyelectrolytes: Evaluation of enthalpy and entropy changes of conformational transitions (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 203-216 
    Details
    ISSN: 0006-3525
    Keywords: conformational stability ; biological polyelectrolytes ; enthalpy ; entropy ; conformational transitions ; carrageenan ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new method is proposed for the determination of the enthalpy and entropy changes of nonionic origin upon conformational transition of linear biopolyelectrolytes in solution. For all transition midpoints, defined by given temperature and ionic strength, the total free energy change of the system is zero, which means that the nonionic contribution to the free energy change is equal in value and opposite in sign to the polyelectrolytic one. The counterion condensation theory of linear polyelectrolytes provides for the appropriate analytical expression to be used in such calculations. Linear plots of the proper functions of the calculated free energy changes vs the proper functions of temperature allows for the determination of the enthalpic and entropic terms of the nonionic free energy change of transition.The method has been applied to the extensive available data of the ion-induced conformational change of κ-carrageenan, a linear sulfated galactan extracted from seaweeds. The method has proved very successful, with the results showing a remarkable convergency of the enthalpy values for different monovalent counterions. On the other hand, the above approach has made it possible to explain the known effect of counterion specificity on the transition by a small difference in the nonionic entropic contributions. © 1998 John Wiley & Sons, Inc. Biopoly 45: 203-216, 1998
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 81
    Electronic Resource
    Electronic Resource
    UV resonance Raman spectroscopy of DNA and protein constituents of viruses: Assignments and cross sections for excitations at 257, 244, 238, and 229 nm (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 247-256 
    Details
    ISSN: 0006-3525
    Keywords: uv resonance Raman spectroscopy ; Raman cross section ; hypochromism ; DNA ; deoxynucleoside ; protein ; aromatic amino acid ; virus assembly ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ultraviolet resonance Raman (UVRR) spectra of H2O and D2O solutions of the nucleoside (dA, dG, dC, dT) and aromatic amino acid (Phe, Trp, Tyr) constituents of DNA viruses have been obtained with laser excitation wavelengths of 257, 244, 238, and 229 nm. Using the 981 cm-1 marker of Na2SO4 as an internal standard, Raman frequencies and scattering cross sections were evaluated for all prominent UVRR bands at each excitation wavelength. The results show that UVRR cross sections of both the nucleosides and amino acids are strongly dependent on excitation wavelength and constitute sensitive and selective probes of the residues. The results provide a library of UVRR marker bands for structural analysis of DNA viruses and other nucleoprotein assemblies. © 1998 John Wiley & Sons, Inc. Biopoly 45: 247-256, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 82
    Electronic Resource
    Electronic Resource
    Lumbricus terrestris hemoglobin: A comparison of small-angle X-ray scattering and cryoelectron microscopy data (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 289-298 
    Details
    ISSN: 0006-3525
    Keywords: hemoglobin ; hexagonal bilayer ; Lumbricus ; electron microscopy ; three-dimensional reconstruction ; small-angle x-ray scattering ; three-dimensional models ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The quaternary structure of Lumbricus terrestris hemoglobin was investigated by small-angle x-ray scattering (SAXS). Based on the SAXS data from several independent experiments, a three-dimensional (3D) consensus model was established to simulate the solution structure of this complex protein at low resolution (about 3 nm) and to yield the particle dimensions. The model is built up from a large number of small spheres of different weights, a result of the two-step procedure used to calculate the SAXS model. It accounts for the arrangement of 12 subunits in a hexagonal bilayer structure and for an additional central unit of cylinder-like shape. This model provides an excellent fit of the experimental scattering curve of the protein up to h = 1 nm-1 and a nearly perfect fit of the experimental distance distribution function p(r) in the whole range. Scattering curves and p(r) functions were also calculated for low-resolution models based on 3D reconstructions obtained by cryoelectron microscopy (EM). The calculated functions of these models also provide a very good fit of the experimental scattering curve (even at h 〉 1 nm-1) and p(r) function, if hydration is taken into account and the original model coordinates are slightly rescaled. The comparison of models reveals that both the SAXS-based and the EM-based model lead to a similar simulation of the protein structure and to similar particle dimensions. The essential differences between the models concern the hexagonal bilayer arrangement (eclipsed in the SAXS model, one layer slightly rotated in the EM model), and the mass distribution, mainly on the surface and in the central part of the protein complex. © John Wiley & Sons, Inc. Biopoly 45: 289-298, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 83
    Electronic Resource
    Electronic Resource
    Conformational changes due to vicinal glycosylation: The branched α-l-Rhap(1-2)[β-d-Galp(1-3)]-β-d-Glc1-OMe trisaccharide compared with its parent disaccharides* (1998)
    New York : Wiley-Blackwell
    Biopolymers 46 (1998), S. 417-432 
    Details
    ISSN: 0006-3525
    Keywords: conformational changes ; vicinal glycosylation ; branched α-l-Rhap(1-2)[β-d-Galp(1-3)]-β-d-Glc1-OMe trisaccharide ; parent disaccharides ; hydrogen bond ; isotope effect ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformations of the α-l-Rhap(1-2)-β-d-Glc1-OMe and β-d-Galp(1-3)-β-d-Glc1-OMe disaccharides and the branched title trisaccharide were examined in DMSO-d6 solution by 1H-nmr. The distance mapping procedure was based on rotating frame nuclear Overhauser effect (NOE) constraints involving C- and O-linked protons, and hydrogen-bond constraints manifested by the splitting of the OH nmr signals for partially deuteriated samples. An “isotopomer-selected NOE” method for the unequivocal identification of mutually hydrogen-bonded hydroxyl groups was suggested. The length of hydrogen bonds thus detected is considered the only one motionally nonaveraged nmr-derived constraint. Molecular mechanics and molecular dynamics methods were used to model the conformational properties of the studied oligosaccharides. Complex conformational search, relying on a regular Φ,Ψ-grid based scanning of the conformational space of the selected glycosidic linkage, combined with simultaneous modeling of different allowed orientations of the pendant groups and the third, neighboring sugar residue, has been carried out. Energy minimizations were performed for each member of the Φ,Ψ grid generated set of conformations. Conformational clustering has been done to group the minimized conformations into families with similar values of glycosidic torsion angles. Several stable syn and anti conformations were found for the 1→2 and 1→3 bonds in the studied disaccharides. Vicinal glycosylation affected strongly the occupancy of conformational states in both branches of the title trisaccharide. The preferred conformational family of the trisaccharide (with average Φ,Ψ values of 38°, 17° for the 1→2 and 48°, 1° for the 1→3 bond, respectively) was shown by nmr to be stabilized by intramolecular hydrogen bonding between the nonbonded Rha and Gal residues. © 1998 John Wiley & Sons, Inc. Biopoly 46: 417-432, 1998
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 84
    Electronic Resource
    Electronic Resource
    Buffer dependence of refractive index increments of protein solutions (1998)
    New York : Wiley-Blackwell
    Biopolymers 46 (1998), S. 489-492 
    Details
    ISSN: 0006-3525
    Keywords: refractive index increment ; proteins ; solvent ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The refractive index increment of a protein solution is a property not only of the protein, but also of the solvent. This is demonstrated theoretically and confirmed experimentally using analytical interferometry. © 1998 John Wiley & Sons, Inc. Biopoly 46: 489-492, 1998
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 85
    Electronic Resource
    Electronic Resource
    Editor's comments (1998)
    New York : Wiley-Blackwell
    Biopolymers 47 (1998), S. 1-1 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 86
    Electronic Resource
    Electronic Resource
    Conformational behavior of the HAV-VP3(110-121) peptidic sequence and synthetic analogs in membrane environments studied by CD and computational methods (1998)
    New York : Wiley-Blackwell
    Biopolymers 45 (1998), S. 479-492 
    Details
    ISSN: 0006-3525
    Keywords: hepatitis A ; synthetic peptides ; CD ; liposomes ; computational study ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present study was undertaken to examine the structural features that may be important to explain the immunogenicity of the (110-121) peptide sequence (FWRGDLVFDFQV) of VP3 capsid protein of hepatitis A virus. A conformational analysis of the preferred conformations by CD and molecular mechanics was carried out. Present results suggest that the interaction with liposomes as biomembrane model induces and stabilizes the amphipathic β-structure of the peptide.To study the contribution of amino acid replacements at the RGD tripeptide as well as the influence of the peptide chain length on peptide conformation, solid-phase peptide synthesis of several peptide analogs was carried out and the peptide conformation was studied using CD spectroscopy. The results show that the RGD sequence is necessary to induce the β-structure in the presence of liposomes. © 1998 John Wiley & Sons, Inc. Biopoly 45: 479-492, 1998
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 87
    Electronic Resource
    Electronic Resource
    Liquid crystal formation in DNA fragment solutions (1998)
    New York : Wiley-Blackwell
    Biopolymers 46 (1998), S. 31-37 
    Details
    ISSN: 0006-3525
    Keywords: DNA liquid crystals ; DNA fragments ; screened Coulomb interactions ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The critical volume fractions pertaining to the formation of DNA liquid crystals were obtained from polarization microscopy, 31P-nmr, and phase separation experiments. The DNA length (approximately one to two times the persistence length 50 nm), ionic strength, and counterion variety dependencies are reported. The cholesteric-isotropic transition is interpreted in terms of the coexistence equations, which are derived from the solution free energy including orientational entropy and excluded volume effects. With the wormlike chain as reference system, the electrostatic contribution to the free energy is evaluated as a thermodynamic perturbation in the second virial approximation with a Debye-Hückel potential of mean force. The hard core contribution has been evaluated with scaled particle theory and/or a simple generalization of the Carnahan-Starling equation of state for hard spheres. For sufficiently high ionic strengths, the agreement is almost quantitative. At lower amounts of added salt deviations are observed, which are tentatively attributed to counterion screening effects. The contour length dependence agrees with a DNA persistence length 50 nm. © 1998 John Wiley & Sons, Inc. Biopoly 46: 31-37, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 88
    Electronic Resource
    Electronic Resource
    Gelation of gelatin observation in the bulk and at the air-water interface (1998)
    New York : Wiley-Blackwell
    Biopolymers 46 (1998), S. 245-252 
    Details
    ISSN: 0006-3525
    Keywords: gelatin ; gelation ; atomic force microscopy ; interfacial rheology ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Gelation of gelatin under various conditions has been followed by atomic force microscopy (AFM) with the objective of understanding more fully the structure formed during the gelation process. AFM images were obtained of the structures formed from both the bulk sol and in surface films during the onset of gelation. While gelation occurred in the bulk sol, the extent of helix formation was monitored by measurements of optical rotation, and the molecular aggregation was imaged by AFM. Interfacial gelatin films formed at the air-water interface were also studied. Measurements of surface tension and surface rheology were made periodically and Langmuir-Blodgett films were drawn from the interface to allow AFM imaging of the structure of the interfacial layer as a function of time. Structural studies reveal that at low levels of helical content the gelatin molecules assemble into aggregates containing short segments of dimensions comparable to those expected for gelatin triple helices. With time larger fibrous structures appear whose dimensions suggest that they are bundles of triple helices. As gelation proceeds, the number density of fibers increases at the expense of the smaller aggregates, eventually assembling into a fibrous network. The gel structure appears to be sensitive to the thermal history, and this is particularly important in determining the structure and properties of the interfacial films. © 1998 John Wiley & Sons, Inc. Biopoly 46: 245-252, 1998
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 89
    Electronic Resource
    Electronic Resource
    Ribozyme chemogenetics (1998)
    New York : Wiley-Blackwell
    Biopolymers 48 (1998), S. 65-81 
    Details
    ISSN: 0006-3525
    Keywords: nucleotide analogue interference mapping ; phosphorothioate ; group I intron ; interference suppression ; RNA ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this review I will outline several chemogenetic approaches used to determine the chemical basis of large ribozyme function and structure. The term chemogenetics was first used to describe site-specific functional group modification experiments in the analysis of DNA-protein interactions. Within the past few years equivalent experiments have been performed on large catalytic RNAs using both single-site substitution and interference mapping techniques with nucleotide analogues. While functional group mutagenesis is an important aspect of a chemogenetic approach, chemical correlates to genetic revertants and suppressors must also be realized for the genetic analogy to be intellectually valid and experimentally useful. Several examples of functional group revertants and suppressors have now been obtained within the Tetrahymena group I ribozyme. These experiments define an ensemble of tertiary hydrogen bonds that have made it possible to construct a detailed model of the ribozyme catalytic core. The model includes a functionally important monovalent metal ion binding site, a wobble-wobble receptor motif for helix-helix packing interactions, and a minor groove triple helix. © 1998 John Wiley & Sons, Inc. Biopoly 48: 65-81, 1998
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 90
    Electronic Resource
    Electronic Resource
    Design, synthesis, and analysis of conformationally constrained nucleic acids (1998)
    New York : Wiley-Blackwell
    Biopolymers 48 (1998), S. 83-96 
    Details
    ISSN: 0006-3525
    Keywords: nucleic acid ; disulfide cross-link ; structure ; dynamics ; stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this review I discuss straightforward and general methods to modify nucleic acid structure with disulfide cross-links. A motivating factor in developing this chemistry was the notion that disulfide bonds would be excellent tools to probe the structure, dynamics, thermodynamics, folding, and function of DNA and RNA, much in the way that cystine cross-links have been used to study proteins. The chemistry described has been used to synthesize disulfide cross-linked hairpins and duplexes, higher order structures like triplexes, nonground-state conformations, and tRNAs. Since the cross-links form quantitatively by mild air oxidation and do not perturb either secondary or tertiary structure, this modification should prove quite useful for the study of nucleic acids. © 1998 John Wiley & Sons, Inc. Biopoly 48: 83-96, 1998
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 91
    Electronic Resource
    Electronic Resource
    On the role of magnesium ions in RNA stability (1998)
    New York : Wiley-Blackwell
    Biopolymers 48 (1998), S. 113-135 
    Details
    ISSN: 0006-3525
    Keywords: divalent cations ; magnesium ; RNA ; ion binding ; RNA folding ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Divalent cations, like magnesium, are crucial for the structural integrity and biological activity of RNA. In this article, we present a picture of how magnesium stabilizes a particular folded form of RNA. The overall stabilization of RNA by Mg2+ is given by the free energy of transferring RNA from a reference univalent salt solution to a mixed salt solution. This term has favorable energetic contributions from two distinct modes of binding: diffuse binding and site binding. In diffuse binding, fully hydrated Mg ions interact with the RNA via nonspecific long-range electrostatic interactions. In site binding, dehydrated Mg2+ interacts with anionic ligands specifically arranged by the RNA fold to act as coordinating ligands for the metal ion. Each of these modes has a strong coulombic contribution to binding; however, site binding is also characterized by substantial changes in ion solvation and other nonelectrostatic contributions. We will show how these energetic differences can be exploited to experimentally distinguish between these two classes of ions using analyses of binding polynomials. We survey a number of specific systems in which Mg2+-RNA interactions have been studied. In well-characterized systems such as certain tRNAs and some rRNA fragments these studies show that site-bound ions can play an important role in RNA stability. However, the crucial role of diffusely bound ions is also evident. We emphasize that diffuse binding can only be described rigorously by a model that accounts for long-range electrostatic forces. To fully understand the role of magnesium ions in RNA stability, theoretical models describing electrostatic forces in systems with complicated structures must be developed. © 1999 John Wiley & Sons, Inc. Biopoly 48: 113-135, 1998
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 92
    Electronic Resource
    Electronic Resource
    Spatial configuration of polynucleotide chains. II. Conformational energies and the average dimensions of polyribonucleotidesFrom the thesis submitted by Wilma K. Olson in fulfillment of the requirements for the degree of Doctor of Philosophy, Stanford University, 1971. (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 25-56 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational energies are calculated for pairs of successive bond rotations within an internal residue of a polyribonucleotide chain. Contributions to these energies include bond torsional strain, van der Waals repulsions, London attractions, electrostatic interactions, and inductive interactions between nonbonded atoms in the nucleotide repeat unit. The average dimensions of unperturbed random-coil polyribonucleotide chains are then evaluated on the basis of energies thus estimated, using for this purpose the previously developed virtual bond treatment. The characteristic ratio \documentclass{article}\pagestyle{empty}\begin{document}$ C_\infty = \mathop {{\rm lim}}\limits_{n \to \infty } (\langle r^2 \rangle_0/nl^2) $\end{document} of the mean-square end-to-end distance calculated for polyribonucleotide chains in which all pentose rings are fixed in a C3′-endo conformation is ≈9; for chains consisting exclusively of C2′-endo units it is ≈25. These values are considerably greater than those obtained by giving equal weight to all conformations judged to be sterically allowed. Satisfactory agreement between the calculations here and experimental values from viscosity and light-scattering studies is achieved by treating the chain as a random copolymer of C3′-endo and C2′-endo conformational isomers. The critical dependence of the characteristic ratio on the rotation about bond C3′-O3′ in the C2′-endo chain, however, obscures the interpretation of chain dimensions. The chain is also treated in higher approximation as a sequence of independent repeat units, each of which consists of six chemical bonds. The characteristic ratio obtained in this manner is 6.5 for the C3′-endo chain and 18.5 for the C2′-endo chain. Finally, the effects of partially stacked conformations in polyribonucleotides are investigated using the virtual bond treatment. Chain dimensions are calculated for random coil poly rA chains in which stacking is introduced by both noncooperative and cooperative processes.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    On hydrogen bonding in amylose (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 315-318 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110124
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Far ultraviolet optical activity of saccharide derivatives. I. Xylan and cellulose acetates (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 291-301 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optial rotatory dispersion (ORD) and Circular dichroism (CD) spectra of several β-1,4 xylan and cellulose acetates and some of their oligomers were investigated. The CD spectra proved considerably superior in terms of information content and interpretability. Comparison of the xylan and cellulose acetate series which also included partially substited cellulose acetates showed that the sign of the CD of the C(6) acetyl was negative. Likewise, the combined contribution of C(1) and C(4) to their equatorially substituted acetyls was positive (with C(1) definitely Positive) and the combined contribution of C(2)eq and C(3)eq negative. The solution conformations of both polysaccharide acetates appeared to be random. The CD of White birch xylan acetate which is substituted on the average at every tenth residue with a 4-O-methyl glucuronic acid substituent, was sensitive to it. The xylan oligomer series also illustrated that CD may be used to determine the degree of polymerization of these oligomers up to about 20.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110122
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Dielectric properties of polyelectrolytes. II. A theory of dielectric increment due to ion fluctuation by a matrix method (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 347-359 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mean square of dipole moment of a linear macromolecule which is responsible for dielectric increment of aqueous polyelectrolyte solutions is calculated by means of a matrix method in which ion binding at discrete sites and the nearest-neighbor interaction are taken into account. On the basis of the relationship between polarization of poly-ion and fluctuation of bound counterions the present theory indicates that the loosely bound ions result in larger increment and otherwise smaller increment. Also, the theory predicts that the dielectric increment has a maximum at an intermediate monovalent-divalent ion ratio when both species coexist. These results are consistent with experiments on polyacrylic acid neutralized with NaOH and Ca(OH)2. At large contents of divalent ions the effect of chelation is also discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance spectra of poly(N-alkylamino acid)s (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 399-408 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 220-MHz NMR spectra of various poly (N-alkylamino acid)s are investigated. Spectra of polysarcosine recorded in various solvents showed fine splittings of the methyl and methylene bands. Comparing the spectrum with that of its model compound, the fine structure of the methyl band of polysarcosine was assigned to four dyad sequences of the cis-trans isomeric state of the main chain amide bonds. Also the methylene band was roughly divided into cis and trans bands. From the temperature dependence of the spectra of polysarcosine, a double coalescence phenomenon was observed, in which the four dyad peaks coalesced into two peaks corresponding to cis and trans, then the two peaks coalesced into one peak. Further, the approximate value of the free energy for the internal rotation of the main chain amide bond was estimated. NMR spectra of various poly(N-alkylglycine)s in methylene chloride solution were also obtained. From the comparsion of their methylene bands, the introduction of the bulky N-alkyl groups was found to increase the cis content of the amide bond.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Physico-chemical description of a condensed form of DNA (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 443-459 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When exposed to a low pH, in various ionic strength conditions and in sufficiently dilute solutions, DNA undergoes a transition, revealed by an increase in optical density. A careful analysis shows that, associated with this transition, there is an effective decrease in absorbance, overcompensated by an increase in scattering. The conditions for the new transition can be summarized conveniently by a graph in a pH-Na+ molarity diagram. If the pH of a DNA solution is progressively lowered at constant Na+ concentration, one finds first the melting transition (I), and at lower pH values, the new transition (II). If the same experiment is performed on pre-denatured DNA, only transition II will be found. If native DNA is brought directly to the low pH conditions, without allowing it to denature irreversibly at intermediate pH values, transition II is reversible (with a small hysteresis effect). DNA, initially native, neutralized after prolonged exposures to the low pH, recovers the buoyant density value of native DNA, along with the absorption and scattering properties of the native state. The experiments are consistent with the interpretation that a new state exists in which DNA, still double stranded, assumes a very compact shape (of the order of 1500 Å in diameter for T2 DNA), with a hyperchromicity value of 10-14% above the native value. Nearly monodisperse suspensions of DNA molecule in this apparent state may be obtained only at very low concentrations (∼0.25 μg/ml). At 1 μg DNA/ml aggregation is noticeable. The possible connection with the condition of intraphage DNA is discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110210
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Macromolecule-small molecule interactions; introduction of additional binding sites in polyethyleneimine by disulfide cross-linkages (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 483-491 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyethyleneimine and its acyl derivatives have been thiolated with thiobutyrolactone and the SH groups introduced have been crosslinked in the presence of and in the absence of methyl orange, respectively. After crosslinking of the polymers, the bound methyl orange was removed. The resultant two kinds of crosslinked polymers have been examined for their ability to bind methyl orange. The polymer crosslinked in the presence of methyl orange shows more binding sites and stronger binding than does the polymer crosslinked in the absence of methyl orange. It seems, therefore, that the conformation of the polymer may be molded to provide sites that can accommodate a specific small molecule.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110213
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Masthead (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110301
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Synthesis and conformations of periodic copolypeptides of L-alanine and glycine (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 563-586 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360110304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...