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  • Kinetics  (77)
  • American Association for the Advancement of Science (AAAS)  (77)
  • Annual Reviews
  • 1990-1994  (77)
  • 1994  (22)
  • 1990  (55)
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  • 1990-1994  (77)
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  • 1
    Publication Date: 1990-08-10
    Description: The stimulation of phospholipase A2 by thrombin and type 2 (P2)-purinergic receptor agonists in Chinese hamster ovary cells is mediated by the G protein Gi. To delineate alpha chain regulatory regions responsible for control of phospholipase A2, chimeric cDNAs were constructed in which different lengths of the alpha subunit of Gs (alpha s) were replaced with the corresponding sequence of the Gi alpha subunit (alpha i2). When a carboxyl-terminal chimera alpha s-i(38), which has the last 38 amino acids of alpha s substituted with the last 36 residues of alpha i2, was expressed in Chinese hamster ovary cells, the receptor-stimulated phospholipase A2 activity was inhibited, although the chimera could still activate adenylyl cyclase. Thus, alpha s-i(38) is an active alpha s, but also a dominant negative alpha i molecule, indicating that the last 36 amino acids of alpha i2 are a critical domain for G protein regulation of phospholipase A2 activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gupta, S K -- Diez, E -- Heasley, L E -- Osawa, S -- Johnson, G L -- DK37871/DK/NIDDK NIH HHS/ -- GM30324/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 10;249(4969):662-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Basic Sciences, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2166341" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/pharmacology ; Animals ; Arachidonic Acid ; Arachidonic Acids/metabolism ; Cell Line ; Chlorides/pharmacology ; Enzyme Activation ; GTP-Binding Proteins/*genetics/metabolism ; Inositol Phosphates/metabolism ; Kinetics ; Lithium/pharmacology ; Lithium Chloride ; Macromolecular Substances ; *Mutation ; Phospholipases/*metabolism ; Phospholipases A/*metabolism ; Phospholipases A2 ; Receptors, Purinergic/drug effects/*physiology ; Restriction Mapping ; Thrombin/antagonists & inhibitors/*pharmacology ; Transfection
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  • 2
    Publication Date: 1990-08-17
    Description: The transcription factor C/EBP uses a bipartite structural motif to bind DNA. Two protein chains dimerize through a set of amphipathic alpha helices termed the leucine zipper. Highly basic polypeptide regions emerge from the zipper to form a linked set of DNA contact surfaces. In the recently proposed a "scissors grip" model, the paired set of basic regions begin DNA contact at a central point and track in opposite directions along the major groove, forming a molecular clamp around DNA. This model predicts that C/EBP must undertake significant changes in protein conformation as it binds and releases DNA. The basic region of ligand-free C/EBP is highly sensitive to protease digestion. Pronounced resistance to proteolysis occurred when C/EBP associated with its specific DNA substrate. Sequencing of discrete proteolytic fragments showed that prominent sites for proteolysis occur at two junction points predicted by the "scissors grip" model. One junction corresponds to the cleft where the basic regions emerge from the leucine zipper. The other corresponds to a localized nonhelical segment that has been hypothesized to contain an N-cap and facilitate the sharp angulation necessary for the basic region to track continuously in the major groove of DNA.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shuman, J D -- Vinson, C R -- McKnight, S L -- New York, N.Y. -- Science. 1990 Aug 17;249(4970):771-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Research Laboratories, Department of Embryology, Baltimore, MD 21210.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2202050" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; CCAAT-Enhancer-Binding Proteins ; Chromatography, High Pressure Liquid ; DNA/*metabolism ; DNA-Binding Proteins/metabolism ; Kinetics ; Leucine ; Macromolecular Substances ; Models, Molecular ; Molecular Sequence Data ; Nuclear Proteins/*metabolism ; Peptide Fragments/metabolism ; Peptide Hydrolases/*metabolism ; Protein Conformation ; Transcription Factors/*metabolism ; Trypsin/metabolism
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  • 3
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-04-06
    Description: The rate of release of guanine nucleotides from the ras proteins (Ras) is extremely slow in the presence of Mg2+. It seemed likely, therefore that a factor might exist to accelerate the release of guanosine diphosphate (GDP), and hence the exchange of GDP for guanosine triphosphate (GTP). Such a factor has now been discovered in rat brain cytosol. Brain cytosol was found to catalyze, by orders of magnitude, the release of guanine nucleotides from recombinant v-H-Ras protein bound with [alpha-32P]GDP. This effect occurred even in the presence of a large excess of Mg2+, but was destroyed by heat or by incubation of the cytosol for an hour at 37 degrees C in the absence of phosphatase inhibitors. The effect was observed with either v-H-Ras or c-H-Ras, but not with p25rab3A, a small G protein with about 30% similarity to Ras. The effect could not be mimicked by addition of recombinant Ras-GAP or purified GEF, a guanine nucleotide exchange factor involved in the regulation of eukaryotic protein synthesis. By gel filtration chromatography, the factor appears to possess a molecular size between 100,000 and 160,000 daltons. This protein (Ras-guanine nucleotide-releasing factor, or Ras-GRF) may be involved in the activation of p21ras.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wolfman, A -- Macara, I G -- CA 43551/CA/NCI NIH HHS/ -- ES 01247/ES/NIEHS NIH HHS/ -- GM 41220/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Apr 6;248(4951):67-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biophysics, University of Rochester Medical Center, NY 14642.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2181667" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Binding, Competitive ; Brain/metabolism ; Cholic Acids ; Cytosol/*metabolism ; Guanine Nucleotides/*metabolism ; Guanosine 5'-O-(3-Thiotriphosphate) ; Guanosine Diphosphate/*metabolism ; Guanosine Triphosphate/analogs & derivatives/metabolism ; Hot Temperature ; Immunosorbent Techniques ; Kinetics ; Magnesium Chloride/pharmacology ; Molecular Weight ; Proto-Oncogene Proteins/*metabolism ; Proto-Oncogene Proteins p21(ras) ; Rats ; Thionucleotides/metabolism
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  • 4
    Publication Date: 1990-11-30
    Description: Conducting gramicidin channels form predominantly by the transmembrane association of monomers, one from each side of a lipid bilayer. In single-channel experiments in planar bilayers the two gramicidin analogs, [Val1]gramicidin A (gA) and [4,4,4-F3-Val1]gramicidin A (F3gA), form dimeric channels that are structurally equivalent and have characteristically different conductances. When these gramicidins were added asymmetrically, one to each side of a preformed bilayer, the predominant channel type was the hybrid channel, formed between two chemically dissimilar monomers. These channels formed by the association of monomers residing in each half of the membrane. These results also indicate that the hydrophobic gramicidins are surprisingly membrane impermeant, a conclusion that was confirmed in experiments in which gA was added asymmetrically and symmetrically to preformed bilayers.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉O'Connell, A M -- Koeppe, R E 2nd -- Andersen, O S -- GM21342/GM/NIGMS NIH HHS/ -- GM34968/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Nov 30;250(4985):1256-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology and Biophysics, Cornell University Medical College, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1700867" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Cell Membrane Permeability ; Chemistry, Physical ; Electric Conductivity ; Gramicidin/*chemistry/metabolism ; Ion Channels/*chemistry/physiology ; Kinetics ; Lipid Bilayers/*chemistry ; Macromolecular Substances ; Molecular Sequence Data ; Physicochemical Phenomena ; Protein Conformation
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  • 5
    Publication Date: 1990-09-28
    Description: The erbB2 oncogene encodes a 185-kilodalton transmembrane protein whose sequence is similar to the epidermal growth factor receptor (EGFR). A 30-kilodalton factor (gp30) secreted from MDA-MB-231 human breast cancer cells was shown to be a ligand for p185erbB2. An antibody to EGFR abolished the tyrosine phosphorylation induced by EGF and transforming growth factor-alpha (TGF-alpha) but only partially blocked that produced by gp30 in SK-BR-3 breast cancer cells. In two cell lines that overexpress erbB2 but do not expresss EGFR (MDA-MB-453 breast cancer cells and a Chinese hamster ovary cell line that had been transfected with erbB2), phosphorylation of p185erbB2 was induced only by gp30. The gp30 specifically inhibited the growth of cells that overexpressed p185erbB2. An antibody to EGFR had no effect on the inhibition of SK-BR-3 cell colony formation obtained with gp30. Thus, it appeared that gp30 interacted directly with the EGFR and erbB2. Direct binding of gp30 to p185erbB2 was confirmed by binding competition experiments, where gp30 was found to displace the p185erbB2 binding of a specific antibody to p185erbB2. The evidence described here suggests that gp30 is a ligand for p185erbB2.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lupu, R -- Colomer, R -- Zugmaier, G -- Sarup, J -- Shepard, M -- Slamon, D -- Lippman, M E -- New York, N.Y. -- Science. 1990 Sep 28;249(4976):1552-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Vincent T. Lombardi Cancer Research Center, Georgetown University Medical Center, Washington, DC 20007.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2218496" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Monoclonal ; Binding, Competitive ; Breast Neoplasms ; Cell Line ; Chromatography, Affinity ; Female ; Humans ; Kinetics ; Ligands ; Molecular Weight ; Phosphorylation ; Protein-Tyrosine Kinases/metabolism ; Proto-Oncogene Proteins/genetics/immunology/*metabolism ; Proto-Oncogenes ; Receptor, Epidermal Growth Factor/isolation & purification/*metabolism ; Transfection
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  • 6
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-05-04
    Description: The amino acid sequences of three fragments of cyanogen bromide-digested human placental inositol 1,2-cyclic phosphate 2-phosphohydrolase, an enzyme of the phosphatidylinositol signaling pathway, are identical to sequences within lipocortin III, a member of a family of homologous calcium- and phospholipid-binding proteins that do not have defined physiological functions. Lipocortin III has also been previously identified as placental anticoagulant protein III (PAP III) and calcimedin 35 alpha. Antibodies to PAP III detected PAP III and inositol 1,2-cyclic phosphate 2-phosphohydrolase with identical reactivity on immunoblotting. In addition, inositol 1,2-cyclic phosphate 2-phosphohydrolase was stimulated by the same acidic phospholipids that bind lipocortins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ross, T S -- Tait, J F -- Majerus, P W -- HLBI 14147/HL/NHLBI NIH HHS/ -- HLBI 16634/HL/NHLBI NIH HHS/ -- HLBI 40801/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 May 4;248(4955):605-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Internal Medicine, Washington University School of Medicine, St Louis, MO 63110.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2159184" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Annexin A3 ; Annexins ; Calcium-Binding Proteins/*genetics ; Female ; Humans ; Immunoblotting ; Kinetics ; Molecular Sequence Data ; Phosphoric Diester Hydrolases/*genetics/isolation & purification/metabolism ; Placenta/*enzymology ; Pregnancy
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  • 7
    Publication Date: 1990-09-28
    Description: Heparin-binding growth factor-1 (HBGF-1) is an angiogenic polypeptide mitogen for mesoderm- and neuroectoderm-derived cells in vitro and remains biologically active after truncation of the amino-terminal domain (HBGF-1 alpha) of the HBGF-1 beta precursor. Polymerase chain reaction mutagenesis and prokaryotic expression systems were used to prepare a mutant of HBGF-1 alpha lacking a putative nuclear translocation sequence (amino acid residues 21 to 27; HBGF-1U). Although HBGF-1U retains its ability to bind to heparin, HBGF-1U fails to induce DNA synthesis and cell proliferation at concentrations sufficient to induce intracellular receptor-mediated tyrosine phosphorylation and c-fos expression. Attachment of the nuclear translocation sequence from yeast histone 2B at the amino terminus of HBGF-1U yields a chimeric polypeptide (HBGF-1U2) with mitogenic activity in vitro and indicates that nuclear translocation is important for this biological response.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Imamura, T -- Engleka, K -- Zhan, X -- Tokita, Y -- Forough, R -- Roeder, D -- Jackson, A -- Maier, J A -- Hla, T -- Maciag, T -- HL 32348/HL/NHLBI NIH HHS/ -- HL 35627/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Sep 28;249(4976):1567-70.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Biology, Jerome H. Holland Laboratory for the Biomedical Sciences, American Red Cross, Rockville, MD 20855.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1699274" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Binding, Competitive ; Cattle ; Cell Division/drug effects ; Cell Line ; Cell Nucleus/metabolism ; Cells, Cultured ; DNA Replication/drug effects ; Endothelium, Vascular/drug effects/metabolism ; Fibroblast Growth Factor 1/*genetics/metabolism/pharmacology ; Kinetics ; Mice ; Mitogens/pharmacology ; Molecular Sequence Data ; *Mutation ; Oligonucleotide Probes ; Receptors, Mitogen/metabolism ; Receptors, Vascular Endothelial Growth Factor ; Recombinant Proteins/metabolism/pharmacology ; Transcription, Genetic/drug effects
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  • 8
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-06-29
    Description: Soluble and hydrophobic lipid breakdown products have a variety of important signaling roles in cells. Here sphingoid bases derived in cells from sphingolipid breakdown are shown to have a potent and direct effect in mediating calcium release from intracellular stores. Sphingosine must be enzymically converted within the cell to a product believed to be sphingosine-1-phosphate, which thereafter effects calcium release from a pool including the inositol 1,4,5-trisphosphate-sensitive calcium pool. The sensitivity, molecular specificity, and reversibility of the effect on calcium movements closely parallel sphingoid base-mediated inhibition of protein kinase C. Generation of sphingoid bases in cells may activate a dual signaling pathway involving regulation of calcium and protein kinase C, comparable perhaps to the phosphatidylinositol and calcium signaling pathway.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ghosh, T K -- Bian, J -- Gill, D L -- NS19304/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1990 Jun 29;248(4963):1653-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Chemistry, University of Maryland School of Medicine, Baltimore 21201.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2163543" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Diphosphate/pharmacology ; Animals ; Calcimycin/pharmacology ; Calcium/*metabolism ; Cell Line ; Kinetics ; Phosphoric Monoester Hydrolases/metabolism ; Phosphorylcholine/analogs & derivatives/pharmacology ; Protein Kinase C/metabolism ; Second Messenger Systems/drug effects ; Sphingosine/*analogs & derivatives/*pharmacology ; Thermodynamics
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  • 9
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-10-12
    Description: Voltage-dependent ion channels are responsible for electrical signaling in neurons and other cells. The main classes of voltage-dependent channels (sodium-, calcium-, and potassium-selective channels) have closely related molecular structures. For one member of this superfamily, the transiently voltage-activated Shaker H4 potassium channel, specific amino acid residues have now been identified that affect channel blockade by the small ion tetraethylammonium, as well as the conduction of ions through the pore. Furthermore, variation at one of these amino acid positions among naturally occurring potassium channels may account for most of their differences in sensitivity to tetraethylammonium.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉MacKinnon, R -- Yellen, G -- GM 43949/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Oct 12;250(4978):276-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, MA 02115.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2218530" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Electric Conductivity ; Kinetics ; Membrane Potentials/drug effects ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Oligonucleotide Probes ; Potassium Channels/drug effects/genetics/*physiology ; Tetraethylammonium ; Tetraethylammonium Compounds/*pharmacology
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  • 10
    Publication Date: 1990-02-16
    Description: Sulfonylurea-sensitive adenosine triphosphate (ATP)-regulated potassium (KATP) channels are present in brain cells and play a role in neurosecretion at nerve terminals. KATP channels in substantia nigra, a brain region that shows high sulfonylurea binding, are inactivated by high glucose concentrations and by antidiabetic sulfonylureas and are activated by ATP depletion and anoxia. KATP channel inhibition leads to activation of gamma-aminobutyric acid (GABA) release, whereas KATP channel activation leads to inhibition of GABA release. These channels may be involved in the response of the brain to hyper- and hypoglycemia (in diabetes) and ischemia or anoxia.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Amoroso, S -- Schmid-Antomarchi, H -- Fosset, M -- Lazdunski, M -- New York, N.Y. -- Science. 1990 Feb 16;247(4944):852-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut de Pharmacologie Moleculaire et Cellulaire, UPR 411 du CNRS, Valbonne, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2305257" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/*physiology ; Animals ; Cell Hypoxia ; Deoxyglucose/pharmacology ; Glucose/metabolism/*pharmacology ; Hypoglycemic Agents/*pharmacology ; In Vitro Techniques ; Kinetics ; Oligomycins/pharmacology ; Potassium/pharmacology ; Potassium Channels/drug effects/*physiology ; Rubidium/metabolism ; Structure-Activity Relationship ; Substantia Nigra/drug effects/*physiology ; gamma-Aminobutyric Acid/*metabolism
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  • 11
    Publication Date: 1990-05-04
    Description: Platelet-derived growth factor (PDGF) stimulates phospholipase C (PLC) activity and the phosphorylation of the gamma isozyme of PLC (PLC-gamma) in vitro and in living cells. The role of PLC-gamma in the phosphoinositide signaling pathway was addressed by examining the effect of overexpression of PLC-gamma on cellular responses to PDGF. Overexpression of PLC-gamma correlated with PDGF-induced tyrosine phosphorylation of PLC-gamma and with PDGF-induced breakdown of phosphatidylinositol 4,5-bisphosphate (PIP2). However, neither bradykinin- nor lysophosphatidic acid-induced phosphoinositide metabolism was enhanced in the transfected cells, suggesting that the G protein-coupled phosphoinositide responses to these ligands are mediated by other PLC isozymes. The enhanced PDGF-induced generation of inositol trisphosphate (IP3) did not enhance intracellular calcium signaling or influence PDGF-induced DNA synthesis. Thus, enzymes other than PLC-gamma may limit PDGF-induced calcium signaling and DNA synthesis. Alternatively, PDGF-induced calcium signaling and DNA synthesis may use biochemical pathways other than phosphoinositide metabolism for signal transduction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Margolis, B -- Zilberstein, A -- Franks, C -- Felder, S -- Kremer, S -- Ullrich, A -- Rhee, S G -- Skorecki, K -- Schlessinger, J -- New York, N.Y. -- Science. 1990 May 4;248(4955):607-10.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Rorer Biotechnology, King of Prussia, PA 19406.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2333512" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/physiology ; Cattle ; Cell Division/*drug effects ; Cells, Cultured ; DNA Replication/drug effects ; Genetic Vectors ; Inositol Phosphates/metabolism ; Isoenzymes/biosynthesis/*genetics/metabolism ; Kinetics ; Mice ; Platelet-Derived Growth Factor/*pharmacology ; Second Messenger Systems/*drug effects ; Transfection ; Type C Phospholipases/biosynthesis/*genetics/metabolism
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  • 12
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-08-17
    Description: An antibody elicited to a distorted N-methyl porphyrin catalyzed metal ion chelation by the planar porphyrin. At fixed Zn2+ and Cu2+ concentrations, the antibody-catalyzed reaction showed saturation kinetics with respect to the substrate mesoporphyrin IX (2) and was inhibited by the hapten, N-methylmesoporphyrin IX (1). The turnover number of 80 hour-1 for antibody-catalyzed metallation of 2 with Zn2+ compares with an estimated value of 800 hour-1 for ferrochelatase. The antibody also catalyzed the insertion of Co2+ and Mn2+ into 2, but it did not catalyze the metallation of protoporphyrin IX (3) or deuteroporphyrin IX (4). The antibody has high affinity for several metalloporphyrins, suggesting an approach to developing antibody-heme catalysts for redox or electron transfer reactions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cochran, A G -- Schultz, P G -- New York, N.Y. -- Science. 1990 Aug 17;249(4970):781-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley 94720.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2389144" target="_blank"〉PubMed〈/a〉
    Keywords: Antibodies/*metabolism ; Antigens/immunology ; Catalysis ; Cobalt/metabolism ; Copper/metabolism ; Ferrochelatase/metabolism ; Kinetics ; Manganese/metabolism ; Mesoporphyrins/immunology/metabolism ; Metals/*metabolism ; Porphyrins/*metabolism ; Zinc/metabolism
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  • 13
    Publication Date: 1990-12-21
    Description: Human growth hormone (hGH) elicits a diverse set of biological activities including lactation that derives from binding to the prolactin (PRL) receptor. The binding affinity of hGH for the extracellular binding domain of the hPRL receptor (hPRLbp) was increased about 8000-fold by addition of 50 micromolar ZnCl2. Zinc was not required for binding of hGH to the hGH binding protein (hGHbp) or for binding of hPRL to the hPRLbp. Other divalent metal ions (Ca2+, Mg2+, Cu2+, Mn2+, and Co2+) at physiological concentrations did not support such strong binding. Scatchard analysis indicated a stoichiometry of one Zn2+ per hGH.hPRLbp complex. Mutational analysis showed that a cluster of three residues (His18, His21, and Glu174) in hGH and His188 from the hPRLbp (conserved in all PRL receptors but not GH receptors) are probable Zn2+ ligands. This polypeptide hormone.receptor "zinc sandwich" provides a molecular mechanism to explain why nonprimate GHs are not lactogenic and offers a molecular link between zinc deficiency and its association with altered functions of hGH.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cunningham, B C -- Bass, S -- Fuh, G -- Wells, J A -- New York, N.Y. -- Science. 1990 Dec 21;250(4988):1709-12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Protein Engineering, Genentech, Inc., South San Francisco, CA 94080.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2270485" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Binding Sites ; Chlorides/*pharmacology ; Growth Hormone/*metabolism ; Humans ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Oligonucleotide Probes ; Plasmids ; Protein Conformation ; Receptors, Prolactin/drug effects/genetics/*metabolism ; Restriction Mapping ; Zinc/metabolism/*pharmacology ; *Zinc Compounds
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  • 14
    Publication Date: 1990-11-23
    Description: Detailed kinetic investigations of a catalytic antibody that promotes the hydrolyses of an anilide and phenyl ester show that this catalyst uses a multistep kinetic sequence resembling that found in serine proteases to hydrolyze its substrates, although antibody was elicited to a single transition-state analog. Like the serine proteases the antibody catalyzes the hydrolysis reactions through a putative covalent intermediate, but unlike the enzymes it may use hydroxide ion to cleave the intermediates. Nevertheless, the antibody is a potent catalyst with turnover at higher pH values rivaling that of chymotrypsin. This analysis also reveals that turnover by the antibody is ultimately limited by product desorption, suggesting that improvements in catalytic efficiency may be achieved by judicious changes in the structure of the substrate, so that it is not superimposable on that of the eliciting hapten.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Benkovic, S J -- Adams, J A -- Borders, C L Jr -- Janda, K D -- Lerner, R A -- GM4385801/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Nov 23;250(4984):1135-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Pennsylvania State University, Department of Chemistry, University Park 16802.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2251500" target="_blank"〉PubMed〈/a〉
    Keywords: Acylation ; Aniline Compounds/metabolism ; Antibodies/*metabolism ; Catalysis ; Enzymes/*metabolism ; Hydrogen-Ion Concentration ; Hydrolysis ; Kinetics ; Nitrophenols/metabolism ; Spectrometry, Fluorescence ; Thermodynamics
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  • 15
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-05-11
    Description: Regulated expression of bacterial genes allows a pathogen to adapt to new environmental conditions within the host. The synthesis of over 30 Salmonella proteins is selectively induced during infection of macrophages. Two proteins induced by Salmonella are the heat shock proteins GroEL and DnaK. Two avirulent, macrophage-sensitive mutants of Salmonella synthesize GroEL and DnaK but fail to synthesize different subsets of proteins normally induced within the macrophage. Enhanced expression of selected Salmonella proteins contributes to bacterial survival within macrophages and may also contribute to the apparent immunodominance of heat shock proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Buchmeier, N A -- Heffron, F -- New York, N.Y. -- Science. 1990 May 11;248(4956):730-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1970672" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bacterial Proteins/*biosynthesis/genetics/isolation & purification ; Cell Line ; Chaperonin 60 ; Electrophoresis, Gel, Two-Dimensional ; Electrophoresis, Polyacrylamide Gel ; *Escherichia coli Proteins ; *HSP70 Heat-Shock Proteins ; Heat-Shock Proteins/*biosynthesis/genetics/isolation & purification ; Kinetics ; Macrophages/*microbiology ; Molecular Weight ; Salmonella/*physiology
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  • 16
    Publication Date: 1990-07-20
    Description: Infection by human immunodeficiency virus type-1 (HIV-1) is initiated when its envelope protein, gp120, binds to its receptor, the cell surface glycoprotein CD4. Small molecules, termed N-carbomethoxycarbonyl-prolyl-phenylalanyl benzyl esters (CPFs), blocked this binding. CPFs interacted with gp120 and did not interfere with the binding of CD4 to class II major histocompatibility complex molecules. One CPF isomer, CPF(DD), preserved CD4-dependent T cell function while inhibiting HIV-1 infection of H9 tumor cells and human T cells. Although the production of viral proteins in infected T cells is unaltered by CPF(DD), this compound prevents the spread of infection in an in vitro model system.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Finberg, R W -- Diamond, D C -- Mitchell, D B -- Rosenstein, Y -- Soman, G -- Norman, T C -- Schreiber, S L -- Burakoff, S J -- New York, N.Y. -- Science. 1990 Jul 20;249(4966):287-91.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, MA 02115.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2115689" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigens, CD4/*immunology ; Antiviral Agents/*pharmacology ; Benzyl Compounds/pharmacology ; Cell Line ; Genes, MHC Class II ; HIV Envelope Protein gp120/*immunology ; HIV-1/drug effects/immunology/*physiology ; Humans ; Kinetics ; T-Lymphocytes/immunology
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  • 17
    Publication Date: 1990-07-20
    Description: Epidermal growth factor (EGF) treatment of A-431 epidermoid carcinoma cells elicited a redistribution of phospholipase C-gamma 1 (PLC-gamma 1) from a predominantly cytosolic localization to membrane fractions. The temporal coincidence of this redistribution with EGF stimulation of inositol phosphate formation and EGF increased phosphorylation of PLC-gamma 1 suggests that the membrane association of PLC-gamma 1 is a significant event in second messenger transduction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Todderud, G -- Wahl, M I -- Rhee, S G -- Carpenter, G -- CA24071/CA/NCI NIH HHS/ -- GM07347/GM/NIGMS NIH HHS/ -- T32 AM07491/AM/NIADDK NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1990 Jul 20;249(4966):296-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2374928" target="_blank"〉PubMed〈/a〉
    Keywords: Carcinoma, Squamous Cell ; Cell Line ; Cell Membrane/drug effects/enzymology ; Cytosol/enzymology ; Epidermal Growth Factor/*pharmacology ; Humans ; Isoenzymes/*metabolism ; Kinetics ; Phosphopeptides/isolation & purification ; Protein Binding ; Trypsin ; Type C Phospholipases/*metabolism
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  • 18
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-08-31
    Description: The sodium- and potassium-dependent adenosine triphosphatase (Na+,K(+)-ATPase) maintains the transmembrane Na+ gradient to which is coupled all active cellular transport systems. The R and S alleles of the gene encoding the Na+,K(+)-ATPase alpha 1 subunit isoform were identified in Dahl salt-resistant (DR) and Dahl salt-sensitive (DS) rats, respectively. Characterization of the S allele-specific Na+,K(+)-ATPase alpha 1 complementary DNA identified a leucine substitution of glutamine at position 276. This mutation alters the hydropathy profile of a region in proximity to T3(Na), the trypsin-sensitive site that is only detected in the presence of Na+. This mutation causes a decrease in the rubidium-86 influx of S allele-specific sodium pumps, thus marking a domain in the Na+,K(+)-ATPase alpha subunit important for K+ transport, and supporting the hypothesis of a putative role of these pumps in hypertension.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Herrera, V L -- Ruiz-Opazo, N -- HL 01967/HL/NHLBI NIH HHS/ -- HL 18318/HL/NHLBI NIH HHS/ -- HL 39267/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 31;249(4972):1023-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Section of Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, MA 02118.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1975705" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Cell Membrane/enzymology ; Kidney/enzymology ; Kinetics ; Molecular Sequence Data ; *Mutation ; Polymorphism, Restriction Fragment Length ; Protein Conformation ; Rats ; Rats, Inbred Strains ; Rubidium/*metabolism ; Rubidium Radioisotopes ; Sodium-Potassium-Exchanging ATPase/*genetics/metabolism
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  • 19
    Publication Date: 1990-09-28
    Description: The proliferative potential of human diploid endothelial cells is finite, and cellular senescence in vitro is accompanied by the failure of the endothelial cell to respond to exogenous growth factors. Senescent human endothelial cells were shown to contain high amounts of the transcript for the cytokine interleukin-1 alpha (IL-1 alpha), a potent inhibitor of endothelial cell proliferation in vitro. In contrast, transformed human endothelial cells did not contain detectable IL-1 alpha messenger RNA. Treatment of human endothelial cell populations with an antisense oligodeoxynucleotide to the human IL-1 alpha transcript prevented cell senescence and extended the proliferative life-span of the cells in vitro. Removal of the IL-1 alpha antisense oligomer resulted in the generation of the senescent phenotype and loss of proliferative potential. These data suggest that human endothelial cell senescence in vitro is a dynamic process regulated by the potential intracellular activity of IL-1 alpha.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Maier, J A -- Voulalas, P -- Roeder, D -- Maciag, T -- AG07450/AG/NIA NIH HHS/ -- HL32348/HL/NHLBI NIH HHS/ -- HL35627/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Sep 28;249(4976):1570-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Biology, Jerome H. Holland, Laboratory for the Biomedical Sciences, American Red Cross, Rockville, MD 20855.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2218499" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Cell Division ; Cell Survival ; Cells, Cultured ; Endothelium, Vascular/*cytology/physiology ; Humans ; Interleukin-1/*genetics ; Kinetics ; Molecular Sequence Data ; Oligonucleotide Probes ; RNA, Antisense/*genetics
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  • 20
    Publication Date: 1990-09-21
    Description: Calmodulin is a calcium-binding protein that participates in the transduction of calcium signals. The electric phenotypes of calmodulin mutants of Paramecium have suggested that the protein may regulate some calcium-dependent ion channels. Calcium-dependent sodium single channels in excised patches of the plasma membrane from Paramecium were identified, and their activity was shown to decrease after brief exposure to submicromolar concentrations of calcium. Channel activity was restored to these inactivated patches by adding calmodulin that was isolated from Paramecium to the cytoplasmic surface. This restoration of channel activity did not require adenosine triphosphate and therefore, probably resulted from direct binding of calmodulin, either to the sodium channel itself or to a channel regulator that was associated with the patch membrane.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Saimi, Y -- Ling, K Y -- GM22714/GM/NIGMS NIH HHS/ -- GM36386/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Sep 21;249(4975):1441-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Biology, University of Wisconsin-Madison 53706.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2169650" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/*pharmacology ; Calmodulin/genetics/*pharmacology/physiology ; Cell Membrane/physiology ; Kinetics ; Models, Biological ; Paramecium/*physiology ; Sodium Channels/drug effects/*physiology
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  • 21
    Publication Date: 1990-02-02
    Description: A rapid increase in the RNA levels of the proto-oncogenes c-fos, c-jun, and c-myc was detected after human cytomegalovirus infection. Neither inactivation of viral infectivity with ultraviolet irradiation (with or without psoralen), nor inhibition of translation with cycloheximide or anisomycin adversely affected the enhanced expression of proto-oncogenes, even though these treatments substantially reduced or eliminated the detection of immediate early viral antigens. The increase in the RNA levels of the proto-oncogenes was prevented in the presence of alpha-amanitin or actinomycin D. Thus, expression of these oncogenes appears to be induced by events occurring before the onset of viral protein synthesis, perhaps by the interaction of viral particles with the cell surface.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Boldogh, I -- AbuBakar, S -- Albrecht, T -- New York, N.Y. -- Science. 1990 Feb 2;247(4942):561-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology, University of Texas Medical Branch, Galveston 77550.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1689075" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Line ; Cytomegalovirus/*genetics ; DNA-Binding Proteins/genetics ; *Gene Expression Regulation, Viral ; Humans ; Kinetics ; Lung ; Protein-Tyrosine Kinases/genetics ; Proto-Oncogene Proteins/genetics ; Proto-Oncogene Proteins c-fos ; Proto-Oncogene Proteins c-jun ; Proto-Oncogene Proteins c-myc ; *Proto-Oncogenes ; RNA/genetics/isolation & purification ; Transcription Factors/genetics ; Transcription, Genetic
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  • 22
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-02-16
    Description: Activin, a member of the transforming growth factor beta protein family, was originally isolated from gonadal fluids and stimulates the release of pituitary follicle-stimulating hormone (FSH). Activin has numerous functions in both normal and neoplastic cells. Various cells synthesize activin and have a specific binding site for this peptide. However, the molecular basis for its actions is unknown. A binding protein for activin was purified from rat ovary and was identical to follistatin, a specific inhibitor of FSH release. It is likely that the binding protein participates in the diverse regulatory actions of activin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nakamura, T -- Takio, K -- Eto, Y -- Shibai, H -- Titani, K -- Sugino, H -- New York, N.Y. -- Science. 1990 Feb 16;247(4944):836-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Frontier Research Program, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2106159" target="_blank"〉PubMed〈/a〉
    Keywords: Activins ; Animals ; *Carrier Proteins ; Cells, Cultured ; Female ; Follicle Stimulating Hormone/secretion ; Inhibins/isolation & purification/*metabolism/pharmacology ; Kinetics ; Molecular Weight ; Ovary/*metabolism ; Pituitary Gland/drug effects/secretion ; Protein Binding ; Rats
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  • 23
    Publication Date: 1990-05-04
    Description: Although bacteriophage T4 late promoters are selectively recognized by Escherichia coli RNA polymerase bearing a single protein encoded by T4 gene 55 (gp55), efficient transcription at these promoters requires enhancement by the three T4 DNA polymerase accessory proteins, bound to distal "mobile enhancer" sites. Two principles are shown to govern this transcriptional enhancement: (i) Promoter recognition and communication between the enhancer and the promoter require separate phage-coded proteins. Only RNA polymerase that has the T4 gene 33 protein (gp33) bound to it is subject to enhancement by the three DNA replication proteins. (ii) Transcriptional enhancement in this prokaryotic system is promoter-specific. Promoter specificity is generated by a direct competition of phage T4 gp33 and gp55 with the E. coli promoter recognition protein, sigma 70, for binding to the E. coli RNA polymerase core. Thus, polymerase that contains sigma 70 is competent to transcribe T4 early and middle genes, but lacks the ability to be enhanced by the DNA replication proteins, while polymerase that contains gp55 and gp33 is capable of enhancement via gp33, but its activity is restricted to T4 late promoters by gp55.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Herendeen, D R -- Williams, K P -- Kassavetis, G A -- Geiduschek, E P -- New York, N.Y. -- Science. 1990 May 4;248(4955):573-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, University of California, San Diego, La Jolla 92093.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2185541" target="_blank"〉PubMed〈/a〉
    Keywords: Carrier Proteins/isolation & purification/*physiology ; DNA-Directed RNA Polymerases/*metabolism ; *Enhancer Elements, Genetic ; Escherichia coli/enzymology/*genetics ; Kinetics ; Models, Genetic ; *Promoter Regions, Genetic ; T-Phages/*genetics ; *Transcription Factors ; Viral Proteins/isolation & purification/*metabolism
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  • 24
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-08-17
    Description: The major small nuclear ribonucleoprotein particles (snRNPs) U1, U2, U4 + U6, and U5 have to be transported from the cytoplasm, where they are synthesized, to the nucleus, where they splice pre-messenger RNAs. Since the free core snRNP proteins in the cytoplasm do not enter the nucleus on their own, the nuclear location signal must either reside on the snRNA or be created as a result of snRNA-protein interaction. Here the involvement by the 5'-terminal cap of snRNA molecules in the nucleo-cytoplasmic transport of UsnRNPs has been studied by microinjection of synthetic U1 RNA molecules into frog oocytes; the U1 RNA bore either the normal cap (m3G) or a chemical derivative. Antibodies in the cytoplasm against the m3G cap inhibited the nuclear uptake of U1 snRNP. U1 RNA that was uncapped or contained an unnatural ApppG cap did not enter the nucleus, even though it carried a normal complement of protein molecules. When the ribose ring of the m3G cap was oxidized with periodate, nuclear transport of U1 snRNPs was severely inhibited. Finally, microinjection of m3G cap alone (but not m7G cap) into oocytes severely inhibited the transport of U1 snRNPs to the nucleus. These data suggest that one step in the nuclear uptake of U1 snRNPs involves the m3G cap structure.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fischer, U -- Luhrmann, R -- New York, N.Y. -- Science. 1990 Aug 17;249(4970):786-90.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut fur Molekularbiologie und Tumorforschung, Phillipps-Universitat Marburg, Federal Republic of Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2143847" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biological Transport ; Cell Nucleus/*metabolism ; Cytoplasm/metabolism ; Female ; Guanosine/*analogs & derivatives/physiology ; Kinetics ; Mutation ; Oocytes/*ultrastructure ; RNA Caps/*physiology ; Ribonucleoproteins/genetics/*metabolism ; Ribonucleoproteins, Small Nuclear ; Signal Transduction/*physiology ; Xenopus laevis
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  • 25
    Publication Date: 1990-02-16
    Description: Confocal laser-scanned microscopy and long-wavelength calcium (Ca2+) indicators were combined to monitor both sustained and rapidly dissipating Ca2+ gradients in voltage-clamped sympathetic neurons isolated from the bullfrog. After a brief activation of voltage-dependent Ca2+ channels, Ca2+ spreads inwardly, and reaches the center of these spherical cells in about 300 milliseconds. Although the Ca2+ redistribution in the bulk of the cytosol could be accounted for with a radial diffusion model, local nonlinearities, suggesting either nonuniform Ca2+ entry or spatial buffering, could be seen. After electrical stimulation, Ca2+ signals in the nucleus were consistently larger and decayed more slowly than those in the cytosol. A similar behavior was observed when release of intracellular Ca2+ was induced by caffeine, suggesting that in both cases large responses originate from Ca2+ release sites near or within the nucleus. These results are consistent with an amplification mechanism involving Ca2(+)-induced Ca2+ release, which could be relevant to activity-dependent, Ca2(+)-regulated nuclear events.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hernandez-Cruz, A -- Sala, F -- Adams, P R -- NS1857906/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1990 Feb 16;247(4944):858-62.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Department of Neurobiology and Behavior, State University of New York, Stony Brook 11794.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2154851" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Caffeine/pharmacology ; Calcium/*metabolism ; Calcium Channels/*physiology ; Cytosol/metabolism ; Fluorescent Dyes ; Ganglia, Sympathetic/drug effects/physiology ; In Vitro Techniques ; Kinetics ; Membrane Potentials ; Microscopy, Fluorescence/methods ; Neurons/cytology/drug effects/*physiology ; Rana catesbeiana
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  • 26
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-01-12
    Description: Experiments are presented that confirm earlier predictions that the mode of supply of reactants to a nonlinear (bio)chemical reaction determines or controls concentrations at steady states far from equilibrium. The oxidation of nicotinamide adenine dinucleotide (NADH) catalyzed by the enzyme horseradish peroxidase with continuous input of oxygen was studied; NAD+ is continuously recycled to NADH through a glucose-6-phosphate dehydrogenase system. A comparison of steady-state concentrations is made with an oscillatory oxygen input and a constant input at the same average oxygen input for both modes. By varying the frequency and amplitude of the perturbation (O2 influx), the following may be changed: the average concentration of NADH; the Gibbs free energy difference delta G of the reactants and products at steady state; the average rate of the reaction; the phase relation between the oscillatory rate and delta G; and the dissipation. These results confirm the possibility of an "alternating current chemistry," of control and optimization of thermodynamic efficiency and dissipation by means of external variation of constraints in classes of nonlinear reactions and biological pumps, and of improvements of the yield in such reactions (heterogeneous catalysis, for example).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lazar, J G -- Ross, J -- New York, N.Y. -- Science. 1990 Jan 12;247(4939):189-92.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Stanford University, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2294601" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Chemical Phenomena ; Chemistry ; Glucosephosphate Dehydrogenase/*metabolism ; Horseradish Peroxidase/*metabolism ; Kinetics ; NAD/*metabolism ; Oxidation-Reduction ; Oxygen/metabolism ; Peroxidases/*metabolism ; Thermodynamics
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  • 27
    Publication Date: 1990-05-11
    Description: The endosomal compartment of polarized epithelial cells is a major crossroads for membrane traffic. Proteins entering this compartment from the cell surface are sorted for transport to one of several destinations: recycling to the original cell surface, targeting to lysosomes for degradation, or transcytosis to the opposite surface. The polymeric immunoglobulin receptor (pIgR), which is normally transcytosed from the basolateral to the apical surface, was used as a model to dissect the signals that mediate this sorting event. When exogenous receptor was expressed in Madin-Darby Canine Kidney (MDCK) cells, it was shown that phosphorylation of pIgR at the serine residue at position 664 is required for efficient transcytosis. Replacement of this serine with alanine generated a receptor that is transcytosed only slowly, and appears to be recycled. Conversely, substitution with aspartic acid (which mimics the negative charge of the phosphate group) results in rapid transcytosis. It was concluded that phosphorylation is the signal that directs the pIgR from the endosome into the transcytotic pathway.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Casanova, J E -- Breitfeld, P P -- Ross, S A -- Mostov, K E -- R01-AI-25144/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1990 May 11;248(4956):742-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Anatomy, University of California, San Francisco 94143.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2110383" target="_blank"〉PubMed〈/a〉
    Keywords: Alanine ; Animals ; Aspartic Acid ; Cell Line ; Cell Membrane/immunology/metabolism ; Endocytosis ; Immunoglobulin A/metabolism ; Kinetics ; Ligands ; Membrane Glycoproteins/metabolism ; Molecular Weight ; Mutation ; Phosphorylation ; Rats ; Receptors, Immunologic ; Secretory Component/genetics/*metabolism ; Serine
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  • 28
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-10-26
    Description: The potassium channels encoded by the Drosophila Shaker gene activate and inactivate rapidly when the membrane potential becomes more positive. Site-directed mutagenesis and single-channel patch-clamp recording were used to explore the molecular transitions that underlie inactivation in Shaker potassium channels expressed in Xenopus oocytes. A region near the amino terminus with an important role in inactivation has now been identified. The results suggest a model where this region forms a cytoplasmic domain that interacts with the open channel to cause inactivation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hoshi, T -- Zagotta, W N -- Aldrich, R W -- NS07158/NS/NINDS NIH HHS/ -- NS23294/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1990 Oct 26;250(4980):533-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cellular Physiology, Stanford University, School of Medicine, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2122519" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; DNA/genetics ; Drosophila melanogaster/*genetics ; Electric Conductivity ; Ion Channel Gating/drug effects/*physiology ; Kinetics ; Membrane Potentials/physiology ; Molecular Sequence Data ; Mutagenesis ; Mutagenesis, Site-Directed ; Oocytes/metabolism ; Potassium Channels/genetics/*physiology ; RNA Splicing ; Structure-Activity Relationship ; Trypsin/pharmacology ; Xenopus
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  • 29
    Publication Date: 1990-04-13
    Description: Biosynthetic studies of the prion protein (PrP) have shown that two forms of different topology can be generated from the same pool of nascent chains in cell-free translation systems supplemented with microsomal membranes. A transmembrane form is the predominant product generated in wheat germ (WG) extracts, whereas a completely translocated (secretory) form is the major product synthesized in rabbit reticulocyte lysates (RRL). An unusual topogenic sequence within PrP is now shown to direct this system-dependent difference. The actions of this topogenic sequence were independent of on-going translation and could be conferred to heterologous proteins by the engineering of a discrete set of codons. System-dependent topology conferred by addition of RRL to WG translation products suggests that this sequence interacts with one or more cytosolic factors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lopez, C D -- Yost, C S -- Prusiner, S B -- Myers, R M -- Lingappa, V R -- AG02132/AG/NIA NIH HHS/ -- NS14069/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1990 Apr 13;248(4952):226-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of California, San Francisco 94143.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1970195" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Codon ; Cricetinae ; DNA, Viral/genetics ; Kinetics ; Mesocricetus ; Peptide Mapping ; Plasmids ; PrPSc Proteins ; Prions/*genetics ; Protein Biosynthesis ; Protein Processing, Post-Translational ; Restriction Mapping ; Transcription, Genetic ; Viral Proteins/biosynthesis/*genetics
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  • 30
    Publication Date: 1990-10-26
    Description: The role of defective glucose transport in the pathogenesis of noninsulin-dependent diabetes (NIDDM) was examined in Zucker diabetic fatty rats, a model of NIDDM. As in human NIDDM, insulin secretion was unresponsive to 20 mM glucose. Uptake of 3-O-methylglucose by islet cells was less than 19% of controls. The beta cell glucose transporter (GLUT-2) immunoreactivity and amount of GLUT-2 messenger RNA were profoundly reduced. Whenever fewer than 60% of beta cells were GLUT-2-positive, the response to glucose was absent and hyperglycemia exceeded 11 mM plasma glucose. We conclude that in NIDDM underexpression of GLUT-2 messenger RNA lowers high Km glucose transport in beta cells, and thereby impairs glucose-stimulated insulin secretion and prevents correction of hyperglycemia.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Johnson, J H -- Ogawa, A -- Chen, L -- Orci, L -- Newgard, C B -- Alam, T -- Unger, R H -- DK02700-30/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 1990 Oct 26;250(4980):546-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Diabetes Research, University of Texas, Dallas 75235.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2237405" target="_blank"〉PubMed〈/a〉
    Keywords: 3-O-Methylglucose ; Animals ; Biological Transport ; Diabetes Mellitus/metabolism ; Diabetes Mellitus, Experimental/*metabolism ; Diabetes Mellitus, Type 2/*metabolism ; Female ; *Gene Expression ; Glucose/pharmacology ; Immunoblotting ; Insulin/secretion ; Islets of Langerhans/drug effects/*metabolism ; Kinetics ; Male ; Methylglucosides/metabolism ; Monosaccharide Transport Proteins/*genetics/metabolism ; Obesity ; RNA, Messenger/metabolism ; Rats ; Rats, Inbred Strains ; Rats, Zucker
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  • 31
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-12-21
    Description: A major mechanism for generating tolerance in developing T cells is the intrathymic clonal deletion of T cells that have receptors for those self antigens that are presented on hematopoietic cells. The mechanisms of tolerance induction to antigens not expressed in the thymus remain unclear. Tolerance to self antigens can be generated extrathymically through the induction of clonal nonresponsiveness in T cells with self-reactive receptors. A second mechanism of extrathymic tolerance was identified: clonal elimination of mature T cells with self-reactive receptors that had previously displayed functional reactivity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jones, L A -- Chin, L T -- Longo, D L -- Kruisbeek, A M -- New York, N.Y. -- Science. 1990 Dec 21;250(4988):1726-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biological Response Modifiers Program, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2125368" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Monoclonal/immunology ; Antigens, CD4/analysis ; Antigens, CD8 ; Antigens, Differentiation, T-Lymphocyte/analysis ; Clone Cells ; *Immune Tolerance ; Kinetics ; *Lymphocyte Depletion ; Mice ; Mice, Inbred DBA ; Mice, Inbred Strains ; Spleen/immunology ; T-Lymphocytes/cytology/*immunology ; Thymus Gland/immunology
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  • 32
    Publication Date: 1990-07-20
    Description: Angiotensin II (AII) stimulates rapid increases in the concentration of cytosolic calcium in follicular oocytes from Xenopus laevis. This calcium response was not present in denuded oocytes, indicating that it is mediated by AII receptors on the adherent follicular cells. The endogenous AII receptors differed in their binding properties from mammalian AII receptors expressed on the oocyte surface after injection of rat adrenal messenger RNA. Also, the calcium responses to activation of the amphibian AII receptor, but not the expressed mammalian AII receptor, were blocked reversibly by octanol and intracellular acidification, treatments that inhibit cell coupling through gap junctions. In addition, AII increased the rate of progesterone-induced maturation. Thus, an AII-induced calcium-mobilizing signal is transferred from follicle cells to the oocyte through gap junctions and may play a physiological role in oocyte maturation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sandberg, K -- Bor, M -- Ji, H -- Markwick, A -- Millan, M A -- Catt, K J -- New York, N.Y. -- Science. 1990 Jul 20;249(4966):298-301.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2374929" target="_blank"〉PubMed〈/a〉
    Keywords: Aequorin ; Angiotensin II/*analogs & derivatives/metabolism/*pharmacology ; Animals ; Calcium/*metabolism ; Cytosol/drug effects/metabolism ; Female ; Intercellular Junctions/drug effects/*physiology ; Kinetics ; Luminescence ; Oocytes/drug effects/*physiology ; Progesterone/pharmacology ; Receptors, Angiotensin/metabolism ; *Signal Transduction/drug effects ; Structure-Activity Relationship ; Xenopus laevis
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  • 33
    Publication Date: 1990-08-17
    Description: The interaction of a protein antigen, horse cytochrome c (cyt c), with a monoclonal antibody has been studied by hydrogen-deuterium (H-D) exchange labeling and two-dimensional nuclear magnetic resonance (2D NMR) methods. The H-exchange rate of residues in three discontiguous regions of the cyt c polypeptide backbone was slowed by factors up to 340-fold in the antibody-antigen complex compared with free cyt c. The protected residues, 36 to 38, 59, 60, 64 to 67, 100, and 101, and their hydrogen-bond acceptors, are brought together in the three-dimensional structure to form a contiguous, largely exposed protein surface with an area of about 750 square angstroms. The interaction site determined in this way is consistent with prior epitope mapping studies and includes several residues that were not previously identified. The hydrogen exchange labeling approach can be used to map binding sites on small proteins in antibody-antigen complexes and may be applicable to protein-protein and protein-ligand interactions in general.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3432411/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3432411/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Paterson, Y -- Englander, S W -- Roder, H -- GM 31847/GM/NIGMS NIH HHS/ -- GM 35926/GM/NIGMS NIH HHS/ -- R01 GM031847/GM/NIGMS NIH HHS/ -- S07-RR-05415-28/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 17;249(4970):755-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology, University of Pennsylvania, Philadelphia 19104.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1697101" target="_blank"〉PubMed〈/a〉
    Keywords: Antibodies, Monoclonal/immunology/metabolism ; Antigen-Antibody Complex ; *Binding Sites, Antibody ; Chemical Phenomena ; Chemistry ; Cytochrome c Group/*immunology ; Deuterium ; Epitopes/immunology ; Hydrogen/*metabolism ; Hydrogen Bonding ; Kinetics ; *Magnetic Resonance Spectroscopy ; Molecular Structure ; Protein Conformation
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  • 34
    Publication Date: 1990-05-18
    Description: In Saccharomyces cerevisiae, the product of the CDC25 gene controls the RAS-mediated production of adenosine 3',5'-monophosphate (cAMP). In vivo the carboxyl-terminal third of the CDC25 gene product is sufficient for the activation of adenylate cyclase. The 3'-terminal part of SCD25, a gene of S. cerevisiae structurally related to CDC25, can suppress the requirement for CDC25. Partially purified preparations of the carboxy-terminal domain of the SCD25 gene product enhanced the exchange rate of guanosine diphosphate (GDP) to guanosine triphosphate (GTP) of pure RAS2 protein by stimulating the release of GDP. This protein fragment had a similar effect on the human c-H-ras-encoded p21 protein. Thus, the SCD25 carboxyl-terminal domain can enhance the regeneration of the active form of RAS proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Crechet, J B -- Poullet, P -- Mistou, M Y -- Parmeggiani, A -- Camonis, J -- Boy-Marcotte, E -- Damak, F -- Jacquet, M -- New York, N.Y. -- Science. 1990 May 18;248(4957):866-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratoire de Biochimie, URA 240 du CNRS, Ecole Polytechnique, Palaiseau, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2188363" target="_blank"〉PubMed〈/a〉
    Keywords: *Cell Cycle Proteins ; Escherichia coli/genetics ; Fungal Proteins/genetics/*metabolism/*pharmacology ; Genes, Fungal ; Guanine Nucleotides/*metabolism ; Guanosine Diphosphate/*metabolism ; Guanosine Triphosphate/*metabolism ; Humans ; Kinetics ; Peptide Fragments/*pharmacology ; Plasmids ; Proto-Oncogene Proteins/metabolism ; Proto-Oncogene Proteins p21(ras) ; Recombinant Fusion Proteins ; Saccharomyces cerevisiae/genetics ; *Saccharomyces cerevisiae Proteins ; Transfection ; *ras Proteins ; *ras-GRF1
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  • 35
    Publication Date: 1990-08-03
    Description: Four cloned cDNAs encoding 900-amino acid putative glutamate receptors with approximately 70 percent sequence identity were isolated from a rat brain cDNA library. In situ hybridization revealed differential expression patterns of the cognate mRNAs throughout the brain. Functional expression of the cDNAs in cultured mammalian cells generated receptors displaying alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-selective binding pharmacology (AMPA = quisqualate greater than glutamate greater than kainate) as well as cation channels gated by glutamate, AMPA, and kainate and blocked by 6,7-dinitroquinoxaline-2,3-dione (CNQX).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Keinanen, K -- Wisden, W -- Sommer, B -- Werner, P -- Herb, A -- Verdoorn, T A -- Sakmann, B -- Seeburg, P H -- New York, N.Y. -- Science. 1990 Aug 3;249(4968):556-60.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Neuroendocrinology, University of Heidelberg, F.R.G.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2166337" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Brain/*metabolism/physiology ; Glutamates/metabolism/pharmacology ; Ibotenic Acid/analogs & derivatives/*pharmacology ; Kainic Acid/pharmacology ; Kinetics ; Molecular Sequence Data ; *Multigene Family ; Oligonucleotide Probes ; Organ Specificity ; Oxadiazoles/pharmacology ; Oxazoles/*pharmacology ; Quisqualic Acid ; RNA, Messenger/analysis/genetics ; Rats ; Receptors, Glutamate ; Receptors, Neurotransmitter/drug effects/*genetics/physiology ; Sequence Homology, Nucleic Acid ; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
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  • 36
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-08-03
    Description: Yersinia is the genus of bacteria that is the causative agent in plague or the black death, and on several occasions this organism has killed a significant portion of the world's population. An essential virulence determinant of Yersinia was shown to be a protein tyrosine phosphatase. The recombinant 50-kilodalton Yersinia phosphatase had a specificity for removal of phosphate from Tyr-containing as opposed to Ser/Thr-containing phosphopeptides and proteins. Site-directed mutagenesis was used to show that the Yersinia phosphatase possesses an essential Cys residue required for catalysis. Amino acids surrounding an essential Cys residue are highly conserved, as are other amino acids in the Yersinia and mammalian protein tyrosine phosphatases, suggesting that they use a common catalytic mechanism.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Guan, K L -- Dixon, J E -- 18849/PHS HHS/ -- New York, N.Y. -- Science. 1990 Aug 3;249(4968):553-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Purdue University, West Lafayette, IN 47907.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2166336" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Kinetics ; Molecular Sequence Data ; Phosphoprotein Phosphatases/*genetics/metabolism ; Protein Tyrosine Phosphatases ; Sequence Homology, Nucleic Acid ; Virulence/genetics ; Yersinia/enzymology/genetics/*pathogenicity
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  • 37
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-11-30
    Description: Deep inflation of the lung stimulates surfactant secretion by unknown mechanisms. The hypothesis that mechanical distension directly stimulates type II cells to secrete surfactant was tested by stretching type II cells cultured on silastic membranes. The intracellular Ca2+ concentration was measured in single cells, before and after stretching. A single stretch of alveolar type II cells caused a transient (less than 60 seconds) increase in cytosolic Ca2+ followed by a sustained (15 to 30 minutes) stimulation of surfactant secretion. Both Ca2+ mobilization and exocytosis exhibited dose-dependence to the magnitude of the stretch-stimulus. Thus, mechanical factors can trigger complex cellular events in nonneuron, nonmuscle cells and may be involved in regulating normal lung functions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wirtz, H R -- Dobbs, L G -- HL-24075/HL/NHLBI NIH HHS/ -- HL-34356/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Nov 30;250(4985):1266-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cardiovascular Research Institute, University of California, San Francisco 94143-0130.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2173861" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biomechanical Phenomena ; Calcium/*metabolism ; Cells, Cultured ; Cyclic AMP/metabolism ; Epithelium/physiology ; *Exocytosis ; Kinetics ; Phosphatidylcholines/secretion ; Proteolipids/pharmacology ; Pulmonary Alveoli/*physiology ; Pulmonary Surfactant-Associated Proteins ; Pulmonary Surfactants/pharmacology/secretion ; Rats ; Surface Properties ; Tetradecanoylphorbol Acetate/pharmacology
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  • 38
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-08-24
    Description: During fruiting body morphogenesis of Myxococcus xanthus, cell movement is required for transmission of C-factor, a short range intercellular signaling protein necessary for sporulation and developmental gene expression. Nonmotile cells fail to sporulate and to express C-factor-dependent genes, but both defects were rescued by a simple manipulation of cell position that oriented the cells in aligned, parallel groups. A similar pattern of aligned cells normally results from coordinated recruitment of wildtype cells into multicellular aggregates, which later form mature fruiting bodies. It is proposed that directed cell movement establishes critical contacts between adjacent cells, which are required for efficient intercellular C-factor transmission.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kim, S K -- Kaiser, D -- AGO 2908/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 24;249(4971):926-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Stanford University School of Medicine, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2118274" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins ; Cell Differentiation ; Cell Division ; Cell Movement ; Kinetics ; Morphogenesis ; Myxococcales/*growth & development/physiology/ultrastructure ; Spores, Bacterial/physiology
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  • 39
    Publication Date: 1990-12-07
    Description: A series of dipyridodiazepinones have been shown to be potent inhibitors of human immunodeficiency virus-1 (HIV-1) reverse transcriptase (RT). One compound, BI-RG-587, had a Ki of 200 nanomolar for inhibition of HIV-1 RT that was noncompetitive with respect to deoxyguanosine triphosphate. BI-RG-587 was specific for HIV-1 RT, having no effect on feline and simian RT or any mammalian DNA polymerases. BI-RG-587 inhibited HIV-1 replication in vitro as demonstrated by in situ hybridization, inhibition of protein p24 production, and the lack of syncytia formation in cultured human T cell lines and freshly isolated human peripheral blood lymphocytes. Cytotoxicity studies of BI-RG-587 on human cells showed a high therapeutic index (greater than 8000) in culture.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Merluzzi, V J -- Hargrave, K D -- Labadia, M -- Grozinger, K -- Skoog, M -- Wu, J C -- Shih, C K -- Eckner, K -- Hattox, S -- Adams, J -- HB 67027/HB/NHLBI NIH HHS/ -- HL 42257/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 7;250(4986):1411-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1701568" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antiviral Agents/*pharmacology ; Cell Line ; HIV-1/*drug effects/enzymology/physiology ; Humans ; Kinetics ; Molecular Structure ; Nevirapine ; Nucleic Acid Synthesis Inhibitors ; Pyridines/chemical synthesis/*pharmacology ; *Reverse Transcriptase Inhibitors ; Virus Replication/*drug effects
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  • 40
    Publication Date: 1990-10-05
    Description: To facilitate functional and mechanistic studies of receptor-G protein interactions, [corrected] the human beta 2-adrenergic receptor (h beta-AR) has been expressed in Saccharomyces cerevisiae. This was achieved by placing a modified h beta-AR gene under control of the galactose-inducible GAL1 promoter. After induction by galactose, functional h beta-AR was expressed at a concentration several hundred times as great as that found in any human tissue. As determined from competitive ligand binding experiments, h beta-AR expressed in yeast displayed characteristic affinities, specificity, and stereoselectivity. Partial activation of the yeast pheromone response pathway by beta-adrenergic receptor agonists was achieved in cells coexpressing h beta-AR and a mammalian G protein (Gs) alpha subunit-demonstrating that these components can couple to each other and to downstream effectors when expressed in yeast. This in vivo reconstitution system provides a new approach for examining ligand binding and G protein coupling to cell surface receptors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉King, K -- Dohlman, H G -- Thorner, J -- Caron, M G -- Lefkowitz, R J -- GM21841/GM/NIGMS NIH HHS/ -- HL16037/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Oct 5;250(4977):121-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine (Cardiology), Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2171146" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Base Sequence ; Cell Membrane/physiology ; GTP-Binding Proteins/genetics/*physiology ; Gene Expression ; Humans ; Iodocyanopindolol ; Kinetics ; Macromolecular Substances ; Molecular Sequence Data ; Pindolol/analogs & derivatives/metabolism ; Plasmids ; Promoter Regions, Genetic ; Receptors, Adrenergic, beta/genetics/metabolism/*physiology ; Recombinant Fusion Proteins/metabolism ; Restriction Mapping ; Saccharomyces cerevisiae/genetics/*physiology ; *Signal Transduction
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  • 41
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-08-31
    Description: Major histocompatibility complex (MHC) molecules are exposed to large quantities of self and nonself antigens. It is not known what fraction of MHC molecules needs to be occupied by antigen to induce a T cell response. A quantitative study of naturally processed antigen indicated that T cells could be activated when only 0.03 percent of the total I-Ed purified from antigen-presenting cells (APCs) was occupied with antigen. B cells and macrophages processed hen egg lysozyme (HEL) with different efficiencies, but similar degrees of occupancy were required for T cell stimulation. Higher occupancy was needed for I-Ed-transfected L cells, possibly reflecting the requirement for other accessory molecules for efficient APC-T cell interaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Demotz, S -- Grey, H M -- Sette, A -- AI 09758/AI/NIAID NIH HHS/ -- AI 18634/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 31;249(4972):1028-30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cytel Corporation, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2118680" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antigen-Presenting Cells/*immunology ; B-Lymphocytes/immunology ; Cell Line ; Genes, MHC Class II ; Histocompatibility Antigens Class II/*immunology ; Kinetics ; *Lymphocyte Activation ; Lymphoma ; Macrophages/immunology ; Muramidase/immunology ; T-Lymphocytes/*immunology ; Transfection
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  • 42
    Publication Date: 1990-09-28
    Description: In the central nervous system (CNS), the principal mediators of fast synaptic excitatory neurotransmission are L-glutamate-gated ion channels that are responsive to the glutamate agonist alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA). In each member of a family of four abundant AMPA receptors, a small segment preceding the predicted fourth transmembrane region has been shown to exist in two versions with different amino acid sequences. These modules, designated "flip" and "flop," are encoded by adjacent exons of the receptor genes and impart different pharmacological and kinetic properties on currents evoked by L-glutamate or AMPA, but not those evoked by kainate. For each receptor, the alternatively spliced messenger RNAs show distinct expression patterns in rat brain, particularly in the CA1 and CA3 fields of the hippocampus. These results identify a switch in the molecular and functional properties of glutamate receptors operated by alternative splicing.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sommer, B -- Keinanen, K -- Verdoorn, T A -- Wisden, W -- Burnashev, N -- Herb, A -- Kohler, M -- Takagi, T -- Sakmann, B -- Seeburg, P H -- New York, N.Y. -- Science. 1990 Sep 28;249(4976):1580-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Neuroendocrinology, Center for Molecular Biology, University of Heidelberg, F.R.G.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1699275" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Brain/*metabolism ; DNA/genetics ; Exons ; Genomic Library ; Glutamates/*metabolism/pharmacology ; Ibotenic Acid/*analogs & derivatives/metabolism/pharmacology ; Ion Channels/*physiology ; Kinetics ; Molecular Sequence Data ; Oligonucleotide Probes ; Organ Specificity ; *RNA Splicing ; RNA, Messenger/*genetics ; Rats ; Receptors, AMPA ; Receptors, Glutamate ; Receptors, Neurotransmitter/drug effects/*genetics/physiology ; Recombinant Proteins/metabolism ; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
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  • 43
    Publication Date: 1990-12-07
    Description: The polymerization of actin filaments is involved in growth, movement, and cell division. It has been shown that actin polymerization is controlled by gelsolin, whose interactions with actin are activated by calcium ion (Ca2+) and inhibited by membrane polyphosphoinositides (PPI). A smaller Ca2(+)- and PPI-regulated protein, gCap39, which has 49% sequence identity with gelsolin, has been identified by cDNA cloning and protein purification. Like gelsolin, gCap39 binds to the fast-growing (+) end of actin filaments. However, gCap39 does not sever actin filaments and can respond to Ca2+ and PPI transients independently, under conditions in which gelsolin is ineffective. The coexistence of gCap39 with gelsolin should allow precise regulation of actin assembly at the leading edge of the cell.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yu, F X -- Johnston, P A -- Sudhof, T C -- Yin, H L -- HL 29113/HL/NHLBI NIH HHS/ -- HL 39644/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 7;250(4986):1413-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of Texas Southwestern Medical Center, Dallas 75235-9040.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2255912" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/*metabolism ; Amino Acid Sequence ; Animals ; Cell Line ; DNA/genetics/isolation & purification ; Gene Library ; Humans ; Kidney/metabolism ; Kinetics ; Macrophages/metabolism ; Mice ; Microfilament Proteins/genetics/isolation & purification/*metabolism ; Molecular Sequence Data ; *Nuclear Proteins ; Sequence Homology, Nucleic Acid
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  • 44
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-12-21
    Description: Voltage-activated calcium channels open and close, or gate, according to molecular transition rates that are regulated by transmembrane voltage and neurotransmitters. Here evidence for the control of gating by calcium was found in electrophysiological records of single, L-type calcium channels in heart cells. Conditional open probability analysis revealed that calcium entry during the opening of a single channel produces alterations in gating transition rates that evolve over the course of hundreds of milliseconds. Such alteration of calcium-channel gating by entry of a favored permeant ion provides a mechanism for the short-term modulation of single-ion channels.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yue, D T -- Backx, P H -- Imredy, J P -- 5-T32-GM07057/GM/NIGMS NIH HHS/ -- R29-HL43307/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 21;250(4988):1735-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2176745" target="_blank"〉PubMed〈/a〉
    Keywords: 8-Bromo Cyclic Adenosine Monophosphate/pharmacology ; Animals ; Calcium/*metabolism/pharmacology ; Calcium Channels/drug effects/*physiology ; Guinea Pigs ; Heart/*physiology ; In Vitro Techniques ; *Ion Channel Gating/drug effects ; Kinetics ; Membrane Potentials/drug effects ; Probability ; Ventricular Function
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  • 45
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-02-23
    Description: The atrionatriuretic peptide (ANP) is released from atrial cells in response to increased extracellular fluid volume and reduces sodium absorption by the kidney, thus reducing the blood volume. In this report, ANP suppressed the calcium and sodium currents in rat and guinea pig ventricular myocytes. The suppression of sodium current was caused by enhanced permeability of the sodium channel to calcium without significant changes in the kinetics or the tetrodotoxin sensitivity of the channel. Thus, ANP may regulate the sodium channel by altering its cationic selectivity site to calcium, thereby repressing the sodium current. The suppression of sodium and calcium channels and the resultant depressed excitability of the atrial cells may help to regulate ANP secretion.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sorbera, L A -- Morad, M -- HL16152/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1990 Feb 23;247(4945):969-73.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of Pennsylvania, Philadelphia 19104-6085.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2154853" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Atrial Natriuretic Factor/*pharmacology ; Calcium/metabolism ; Calcium Channels/*metabolism ; Electric Conductivity ; Guinea Pigs ; Heart Ventricles ; Kinetics ; Myocardium/*metabolism ; Permeability ; Rats ; Sodium Channels/drug effects/*metabolism ; Tetrodotoxin/pharmacology
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  • 46
    Publication Date: 1990-12-21
    Description: The progesterone receptor (PR) in the chicken oviduct is a phosphoprotein that regulates gene transcription in the presence of progesterone. Treatment with progesterone in vivo stimulates phosphorylation of the progesterone receptor. With transient transfection assays, the present work has tested whether phosphorylation participates in the regulation of PR-mediated transcription. Treatment with 8-bromo-cyclic adenosine monophosphate (8-Br cAMP), a stimulator of cAMP-dependent protein kinase [protein kinase A (PKA)], mimicked progesterone-dependent, receptor-mediated transcription in the absence of progesterone. Inhibition of PKA blocked hormone action. Treatment with okadaic acid, an inhibitor of protein phosphatases 1 and 2A, stimulated transcription in a manner similar to that of progesterone. These observations suggest that phosphorylation of the PR or other proteins in the transcription complex can modulate PR-mediated transcription in vivo.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Denner, L A -- Weigel, N L -- Maxwell, B L -- Schrader, W T -- O'Malley, B W -- HD-07857/HD/NICHD NIH HHS/ -- HD-22061/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 21;250(4988):1740-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2176746" target="_blank"〉PubMed〈/a〉
    Keywords: 8-Bromo Cyclic Adenosine Monophosphate/pharmacology ; Animals ; Cell Line ; Chickens ; Female ; Gene Expression Regulation ; Kinetics ; Oviducts/metabolism ; Phosphoprotein Phosphatases/antagonists & inhibitors ; Phosphorylation ; Progesterone/*pharmacology ; Receptors, Progesterone/*metabolism ; *Transcription, Genetic/drug effects ; Transfection
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  • 47
    Publication Date: 1990-08-03
    Description: A two-fold (C2) symmetric inhibitor of the protease of human immunodeficiency virus type-1 (HIV-1) has been designed on the basis of the three-dimensional symmetry of the enzyme active site. The symmetric molecule inhibited both protease activity and acute HIV-1 infection in vitro, was at least 10,000-fold more potent against HIV-1 protease than against related enzymes, and appeared to be stable to degradative enzymes. The 2.8 angstrom crystal structure of the inhibitor-enzyme complex demonstrated that the inhibitor binds to the enzyme in a highly symmetric fashion.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Erickson, J -- Neidhart, D J -- VanDrie, J -- Kempf, D J -- Wang, X C -- Norbeck, D W -- Plattner, J J -- Rittenhouse, J W -- Turon, M -- Wideburg, N -- AI 27220/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 3;249(4968):527-33.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Computer-Assisted Molecular Design, Abbott Laboratories, Abbott Park, IL 60064.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2200122" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Drug Design ; Endopeptidases/*metabolism ; Gene Products, pol/*metabolism ; HIV Protease ; HIV-1/*enzymology ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Protease Inhibitors/*pharmacology ; Protein Conformation ; Sugar Alcohols/*pharmacology ; Valine/*analogs & derivatives/pharmacology
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  • 48
    Publication Date: 1990-06-29
    Description: The presence of endothelin, a vasoconstrictor peptide, in the hypothalamus and posterior pituitary suggests that it also regulates neural and other nonvascular target cells. In pituitary gonadotrophs, low doses of endothelin evoked oscillations in the intracellular calcium concentration, and high doses induced a biphasic calcium response. Mobilization of intracellular calcium predominated during the spike phase of the calcium response to endothelin, whereas calcium entry through dihydropyridine-sensitive channels contributed to both the spike and plateau phases of the calcium response. Endothelin was a potent as hypothalamic gonadotropin-releasing hormone (GnRH) in stimulation of gonadotropin release in perifused pituitary cells. Endothelin bound specifically to pituitary cells with a dissociation constant of 70 picomolar, and induced rapid formation of inositol trisphosphate and diacyglycerol. Although intracellular calcium concentration and gonadotropin secretory responses to endothelin were independent to the GnRH receptor, endothelin and GnRH appeared to have a common signal transduction mechanism. These observations suggest that endothelin can act as a neuropeptide to regulate anterior pituitary function.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stojilkovic, S S -- Merelli, F -- Iida, T -- Krsmanovic, L Z -- Catt, K J -- New York, N.Y. -- Science. 1990 Jun 29;248(4963):1663-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2163546" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/*metabolism ; Cells, Cultured ; Cytosol/metabolism ; Endothelins ; Endothelium, Vascular ; Female ; Follicle Stimulating Hormone/*secretion ; Gonadotropin-Releasing Hormone/pharmacology ; Kinetics ; Luteinizing Hormone/*secretion ; Male ; Nifedipine/pharmacology ; Orchiectomy ; Peptides/metabolism/*pharmacology ; Pituitary Gland, Anterior/drug effects/*metabolism/secretion ; Rats ; Rats, Inbred Strains ; Receptors, Cell Surface/metabolism ; Receptors, Endothelin ; Reference Values
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  • 49
    Publication Date: 1990-08-31
    Description: Three closely related genes, GluR1, GluR2, and GluR3, encode receptor subunits for the excitatory neurotransmitter glutamate. The proteins encoded by the individual genes form homomeric ion channels in Xenopus oocytes that are sensitive to glutamatergic agonists such as kainate and quisqualate but not to N-methyl-D-aspartate, indicating that binding sites for kainate and quisqualate exist on single receptor polypeptides. In addition, kainate-evoked conductances are potentiated in oocytes expressing two or more of the cloned receptor subunits. Electrophysiological responses obtained with certain subunit combinations show agonist profiles and current-voltage relations that are similar to those obtained in vivo. Finally, in situ hybridization histochemistry reveals that these genes are transcribed in shared neuroanatomical loci. Thus, as with gamma-aminobutyric acid, glycine, and nicotinic acetylcholine receptors, native kainate-quisqualate-sensitive glutamate receptors form a family of heteromeric proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Boulter, J -- Hollmann, M -- O'Shea-Greenfield, A -- Hartley, M -- Deneris, E -- Maron, C -- Heinemann, S -- NS11549/NS/NINDS NIH HHS/ -- NS28709/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1990 Aug 31;249(4972):1033-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, San Diego, CA 92138.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2168579" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Cloning, Molecular ; Gene Expression ; Glutamates/metabolism ; Hippocampus/metabolism ; Kinetics ; Macromolecular Substances ; Membrane Potentials ; Molecular Sequence Data ; *Multigene Family ; Oocytes/physiology ; Rats ; Receptors, Glutamate ; Receptors, Neurotransmitter/*genetics/physiology ; Sequence Homology, Nucleic Acid ; Transcription, Genetic
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  • 50
    Publication Date: 1990-11-30
    Description: Phospholipase C-gamma 1 (PLC-gamma 1), an isozyme of the phosphoinositide-specific phospholipase C family, which occupies a central role in hormonal signal transduction pathways, is an excellent substrate for the epidermal growth factor (EGF) receptor tyrosine kinase. Epidermal growth factor elicits tyrosine phosphorylation of PLC-gamma 1 and phosphatidylinositol 4,5-bisphosphate hydrolysis in various cell lines. The ability of tyrosine phosphorylation to activate the catalytic activity of PLC-gamma 1 was tested. Tyrosine phosphorylation in intact cells or in vitro increased the catalytic activity of PLC-gamma 1. Also, treatment of EGF-activated PLC-gamma 1 with a tyrosine-specific phosphatase substantially decreased the catalytic activity of PLC-gamma 1. These results suggest that the EGF-stimulated formation of inositol 1,4,5-trisphosphate and diacylglycerol in intact cells results, at least in part, from catalytic activation of PLC-gamma 1 through tyrosine phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nishibe, S -- Wahl, M I -- Hernandez-Sotomayor, S M -- Tonks, N K -- Rhee, S G -- Carpenter, G -- CA43720/CA/NCI NIH HHS/ -- GMO7347/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Nov 30;250(4985):1253-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1700866" target="_blank"〉PubMed〈/a〉
    Keywords: Catalysis ; Diglycerides/metabolism ; Enzyme Activation/drug effects ; Epidermal Growth Factor/pharmacology ; Immunosorbent Techniques ; Inositol 1,4,5-Trisphosphate/metabolism ; Isoenzymes/*metabolism ; Kinetics ; Phosphatidylinositol 4,5-Diphosphate ; Phosphatidylinositol Diacylglycerol-Lyase ; Phosphatidylinositols/metabolism ; Phosphoric Diester Hydrolases/*metabolism ; Phosphorylation ; Phosphotyrosine ; Protein-Tyrosine Kinases/metabolism ; Receptor, Epidermal Growth Factor ; Signal Transduction ; Tyrosine/*analogs & derivatives/metabolism
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  • 51
    Publication Date: 1990-06-29
    Description: Platelet-derived growth factor (PDGF) induction of DNA synthesis is believed to involve activation of phospholipase C (PLC) and subsequent accumulation of inositol 1,4,5-triphosphate [I(1,4,5)P3], increase in intracellular Ca2+, activation of protein kinase C (PKC), and receptor down regulation. Generation of these events is triggered by the tyrosine protein kinase (TPK) activity of the PDGF receptor. The TPK inhibitor genistein blocked PDGF induction of these events, including DNA synthesis, with the exception of receptor down regulation. PDGF-induced phosphotyrosine phosphorylations, including receptor autophosphorylation, were inhibited by genistein. Removal of genistein and PDGF resulted in DNA synthesis without the occurrence of PLC activation. These findings indicate that these early events, with the exception of receptor down regulation, are not necessary for PDGF-induced DNA synthesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hill, T D -- Dean, N M -- Mordan, L J -- Lau, A F -- Kanemitsu, M Y -- Boynton, A L -- CA 2942/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1990 Jun 29;248(4963):1660-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cancer Research Center of Hawaii, University of Hawaii, Honolulu 96813.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2163545" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/metabolism ; Cells, Cultured ; Chlorides/pharmacology ; DNA Replication/*drug effects ; Dimethyl Sulfoxide/pharmacology ; Enzyme Activation ; Genistein ; Inositol Phosphates/metabolism ; Isoflavones/pharmacology ; Kinetics ; Lithium/pharmacology ; Lithium Chloride ; Mice ; Phosphatidylinositol 4,5-Diphosphate ; Phosphatidylinositols/metabolism ; Phosphorylation ; Platelet-Derived Growth Factor/*pharmacology ; Protein Kinase C/metabolism ; Protein-Tyrosine Kinases/metabolism ; Type C Phospholipases/*metabolism
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  • 52
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1990-12-07
    Description: Efficient transport of class I major histocompatibility complex molecules to the cell surface requires association of the class I heavy chain with endogenous peptide and the class I light chain, beta 2-microglobulin (beta 2M). A mutant cell line deficient in beta 2M transports low amounts of nonpeptide-associated heavy chains to the cell surface that can associate with exogenously provided beta 2M and synthetic peptide antigens. Normal beta 2M-sufficient cells grown in serum-free media devoid of beta 2M also require an exogenous source of beta 2M to efficiently bind synthetic peptide. Thus, class I molecules on normal cells do not spontaneously bind or exchange peptides.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vitiello, A -- Potter, T A -- Sherman, L A -- AI-25280/AI/NIAID NIH HHS/ -- CA-25803/CA/NCI NIH HHS/ -- CA-49394/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1990 Dec 7;250(4986):1423-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cytel Corporation, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2124002" target="_blank"〉PubMed〈/a〉
    Keywords: Abelson murine leukemia virus/genetics ; Animals ; Antibodies ; Biological Transport ; Cell Line ; Cell Membrane/immunology ; Cell Transformation, Neoplastic ; Cytotoxicity, Immunologic ; Histocompatibility Antigens Class I/analysis/*metabolism ; Immunoglobulin Heavy Chains/metabolism ; Kinetics ; Mice ; Mice, Inbred Strains ; T-Lymphocytes, Cytotoxic/immunology ; beta 2-Microglobulin/genetics/*metabolism
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  • 53
    Publication Date: 1990-09-21
    Description: The primary structure of lipopolysaccharide binding protein (LBP), a trace plasma protein that binds to the lipid A moiety of bacterial lipopolysaccharides (LPSs), was deduced by sequencing cloned complementary DNA. LBP shares sequence identity with another LPS binding protein found in granulocytes, bactericidal/permeability-increasing protein, and with cholesterol ester transport protein of the plasma. LBP may control the response to LPS under physiologic conditions by forming high-affinity complexes with LPS that bind to monocytes and macrophages, which then secrete tumor necrosis factor. The identification of this pathway for LPS-induced monocyte stimulation may aid in the development of treatments for diseases in which Gram-negative sepsis or endotoxemia are involved.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schumann, R R -- Leong, S R -- Flaggs, G W -- Gray, P W -- Wright, S D -- Mathison, J C -- Tobias, P S -- Ulevitch, R J -- AI 15136/AI/NIAID NIH HHS/ -- AI 25563/AI/NIAID NIH HHS/ -- GM 28485/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1990 Sep 21;249(4975):1429-31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Immunology, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2402637" target="_blank"〉PubMed〈/a〉
    Keywords: *Acute-Phase Proteins ; Amino Acid Sequence ; Animals ; Base Sequence ; Blood Proteins/*genetics ; Carrier Proteins/*genetics/metabolism ; Gene Library ; Humans ; Kinetics ; Lipid A/metabolism ; Lipopolysaccharides/*metabolism/pharmacology ; Male ; *Membrane Glycoproteins ; Molecular Sequence Data ; Oligonucleotide Probes ; Rabbits ; Sequence Homology, Nucleic Acid ; Sheep ; Staphylococcus aureus ; Tumor Necrosis Factor-alpha/biosynthesis
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  • 54
    Publication Date: 1990-08-03
    Description: Human immunodeficiency virus (HIV) frequently causes neurological dysfunction and is abundantly expressed in the central nervous system (CNS) of acquired immunodeficiency syndrome (AIDS) patients with HIV encephalitis or myelopathy. The virus is found mostly in cells of the monocyte-macrophage lineage within the CNS, but the possibility of infection of other glial cells has been raised. Therefore, the effects of different HIV-1 and HIV-2 strains were studied in primary cultures of adult human brain containing microglial cells, the resident CNS macrophages, and astrocytes. These cultures could be productively infected with macrophage-adapted HIV-1 isolates but not with T lymphocyte-adapted HIV-1 isolates or two HIV-2 isolates. As determined with a triple-label procedure, primary astrocytes did not express HIV gag antigens and remained normal throughout the 3-week course of infection. In contrast, virus replicated in neighboring microglial cells, often leading to their cell fusion and death. The death of microglial cells, which normally serve immune functions in the CNS, may be a key factor in the pathogenesis of AIDS encephalitis or myelopathy.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Watkins, B A -- Dorn, H H -- Kelly, W B -- Armstrong, R C -- Potts, B J -- Michaels, F -- Kufta, C V -- Dubois-Dalcq, M -- New York, N.Y. -- Science. 1990 Aug 3;249(4968):549-53.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Viral and Molecular Pathogenesis, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2200125" target="_blank"〉PubMed〈/a〉
    Keywords: Adult ; Brain/*microbiology ; Cells, Cultured ; Fluorescent Antibody Technique ; HIV-1/pathogenicity/*physiology ; HIV-2/pathogenicity/physiology ; Humans ; Kinetics ; Neuroglia/*microbiology ; Species Specificity ; Virus Replication
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  • 55
    Publication Date: 1990-05-04
    Description: A low molecular weight serine protease inhibitor (TAP) was purified from extracts of the soft tick, Ornithodoros moubata. The peptide is a slow, tight-binding inhibitor, specific for factor Xa (Ki = 0.588 +/- 0.054 nM). The inhibitor also acts as an anticoagulant in several human plasma clotting assays in vitro. Its amino acid sequence (60 residues) has limited homology to the Kunitz-type inhibitors. However, unlike other inhibitors of this class, TAP inhibits only factor Xa. It had no effect at a 300-fold molar excess on factor VIIa, kallikrein, trypsin, chymotrypsin, thrombin, urokinase, plasmin, tissue plasminogen activator, elastase, or Staphylococcus aureus V8 protease. TAP's specificity and size suggest that it may have therapeutic value as an anticoagulant.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Waxman, L -- Smith, D E -- Arcuri, K E -- Vlasuk, G P -- New York, N.Y. -- Science. 1990 May 4;248(4955):593-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biological Chemistry Department, Merck Sharp & Dohme Research Laboratories, West Point, PA 19486.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2333510" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Arthropod Proteins ; Blood Coagulation Tests ; Chromatography, Gel ; *Factor Xa Inhibitors ; Humans ; Kinetics ; Molecular Sequence Data ; Peptides/*isolation & purification/pharmacology ; Sequence Homology, Nucleic Acid ; Serine Proteinase Inhibitors/*isolation & purification ; Ticks/*analysis
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  • 56
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-06-24
    Description: The basic notions of transition state theory have been exploited in the past to generate highly selective catalysts from the vast library of antibody molecules in the immune system. These same ideas were used to isolate an RNA molecule, from a large library of RNAs, that catalyzes the isomerization of a bridged biphenyl. The RNA-catalyzed reaction displays Michaelis-Menten kinetics with a catalytic rate constant (kcat) of 2.8 x 10(-5) per minute and a Michaelis constant (Km) of 542 microM; the reaction is competitively inhibited by the planar transition state analog with an inhibition constant (Ki) value of approximately 7 microM. This approach may provide a general strategy for expanding the scope of RNA catalysis beyond those reactions in which the substrates are nucleic acids or nucleic acid derivatives.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Prudent, J R -- Uno, T -- Schultz, P G -- GM08352A/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jun 24;264(5167):1924-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8009223" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; Biphenyl Compounds/chemistry/metabolism ; Catalysis ; Kinetics ; Molecular Sequence Data ; Nucleic Acid Conformation ; Nucleic Acid Denaturation ; Polymerase Chain Reaction ; RNA, Catalytic/chemistry/*metabolism ; Stereoisomerism ; Temperature
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  • 57
    Publication Date: 1994-08-19
    Description: A small molecule called PD 153035 inhibited the epidermal growth factor (EGF) receptor tyrosine kinase with a 5-pM inhibition constant. The inhibitor was specific for the EGF receptor tyrosine kinase and inhibited other purified tyrosine kinases only at micromolar or higher concentrations. PD 153035 rapidly suppressed autophosphorylation of the EGF receptor at low nanomolar concentrations in fibroblasts or in human epidermoid carcinoma cells and selectively blocked EGF-mediated cellular processes including mitogenesis, early gene expression, and oncogenic transformation. PD 153035 demonstrates an increase in potency over that of other tyrosine kinase inhibitors of four to five orders of magnitude for inhibition of isolated EGF receptor tyrosine kinase and three to four orders of magnitude for inhibition of cellular phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fry, D W -- Kraker, A J -- McMichael, A -- Ambroso, L A -- Nelson, J M -- Leopold, W R -- Connors, R W -- Bridges, A J -- New York, N.Y. -- Science. 1994 Aug 19;265(5175):1093-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Company, Ann Arbor, MI 48105.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8066447" target="_blank"〉PubMed〈/a〉
    Keywords: 3T3 Cells ; Animals ; Cell Transformation, Neoplastic/drug effects ; Epidermal Growth Factor/pharmacology ; Fibroblast Growth Factor 2/pharmacology ; Gene Expression/drug effects ; Humans ; Kinetics ; Mice ; Mitosis/drug effects ; Phosphorylation/drug effects ; Platelet-Derived Growth Factor/pharmacology ; Protein-Tyrosine Kinases/antagonists & inhibitors ; Quinazolines/*antagonists & inhibitors ; Receptor, Epidermal Growth Factor/*antagonists & inhibitors ; Tumor Cells, Cultured ; Tyrosine/metabolism
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  • 58
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-09-23
    Description: The functional consequences of single proton transfers occurring in the pore of a cyclic nucleotide-gated channel were observed with patch recording techniques. These results led to three conclusions about the chemical nature of ion binding sites in the conduction pathway: The channel contains two identical titratable sites, even though there are more than two (probably four) identical subunits; the sites are formed by glutamate residues that have a pKa (where K(a) is the acid constant) of 7.6; and protonation of one site does not perturb the pKa of the other. These properties point to an unusual arrangement of carboxyl side-chain residues in the pore of a cation channel.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Root, M J -- MacKinnon, R -- 5 T32 GM083113/GM/NIGMS NIH HHS/ -- GM47400/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Sep 23;265(5180):1852-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neurobiology, Harvard Medical School, Boston, MA 02115.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7522344" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding Sites ; Calcium Channels/metabolism ; Catfishes ; Electric Conductivity ; Hydrogen-Ion Concentration ; Ion Channel Gating ; Ion Channels/chemistry/genetics/*metabolism ; Kinetics ; Molecular Sequence Data ; Mutation ; *Protons ; Sodium/metabolism ; Xenopus
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  • 59
    Publication Date: 1994-09-16
    Description: A reverse protocol for measurements of molecular binding and reactivity by excited-state quenching has been developed in which the quencher, held at a fixed concentration, is titrated by a photoexcitable probe molecule whose decay is monitored. The binding stoichiometries, affinities, and reactivities of the electron-transfer complexes between cytochrome c (Cc) and cytochrome c peroxidase (CcP) were determined over a wide range of ionic strengths (4.5 to 118 millimolar) by the study of photoinduced electron-transfer quenching of the triplet excited state of zinc-substituted Cc (ZnCc) by Fe3+CcP. The 2:1 stoichiometry seen for the binding of Cc to CcP at low ionic strength persists at the physiologically relevant ionic strengths and likely has functional significance. Analysis of the stoichiometric binding and rate constants confirms that one surface domain of CcP binds Cc with a high affinity but with poor electron-transfer quenching of triplet-state ZnCc, whereas a second binds weakly but with a high rate of electron-transfer quenching.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhou, J S -- Hoffman, B M -- HL13531/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1994 Sep 16;265(5179):1693-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Northwestern University, Evanston, IL 60208-3113.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8085152" target="_blank"〉PubMed〈/a〉
    Keywords: Cytochrome c Group/chemistry/*metabolism ; Cytochrome-c Peroxidase/chemistry/*metabolism ; Electron Transport ; Ferric Compounds ; Kinetics ; Osmolar Concentration ; Oxidation-Reduction ; Zinc
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  • 60
    Publication Date: 1994-01-28
    Description: As changes in synaptic strength are thought to be critical for learning and memory, it would be useful to monitor the activity of individual identified synapses on mammalian central neurons. Calcium imaging of cortical neurons grown in primary culture was used to visualize the activation of individual postsynaptic elements by miniature excitatory synaptic currents elicited by spontaneous quantal release. This approach revealed that the probability of spontaneous activity differed among synapses on the same dendrite. Furthermore, synapses that undergo changes in activity induced by glutamate or phorbol ester treatment were identified.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Murphy, T H -- Baraban, J M -- Wier, W G -- Blatter, L A -- New York, N.Y. -- Science. 1994 Jan 28;263(5146):529-32.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7904774" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/*metabolism ; Cells, Cultured ; Cerebral Cortex ; Dendrites/*metabolism ; Glutamates/pharmacology ; Glutamic Acid ; Kinetics ; Microelectrodes ; Neuronal Plasticity ; Neurons/*physiology ; Phorbol Esters/pharmacology ; Rats ; Receptors, N-Methyl-D-Aspartate/physiology ; Synapses/*physiology ; *Synaptic Transmission ; Tetrodotoxin/pharmacology
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  • 61
    Publication Date: 1994-12-09
    Description: AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor channels mediate the fast component of excitatory postsynaptic currents in the central nervous system. Site-selective nuclear RNA editing controls the calcium permeability of these channels, and RNA editing at a second site is shown here to affect the kinetic aspects of these channels in rat brain. In three of the four AMPA receptor subunits (GluR-B, -C, and -D), intronic elements determine a codon switch (AGA, arginine, to GGA, glycine) in the primary transcripts in a position termed the R/G site, which immediately precedes the alternatively spliced modules "flip" and "flop." The extent of editing at this site progresses with brain development in a manner specific for subunit and splice form, and edited channels possess faster recovery rates from desensitization.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lomeli, H -- Mosbacher, J -- Melcher, T -- Hoger, T -- Geiger, J R -- Kuner, T -- Monyer, H -- Higuchi, M -- Bach, A -- Seeburg, P H -- New York, N.Y. -- Science. 1994 Dec 9;266(5191):1709-13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Neuroendocrinology, University of Heidelberg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7992055" target="_blank"〉PubMed〈/a〉
    Keywords: Alternative Splicing ; Amino Acid Sequence ; Animals ; Base Sequence ; Brain/embryology/*metabolism ; Cell Nucleus/metabolism ; Exons ; Glutamic Acid/pharmacology ; Glycine/genetics ; Introns ; Kinetics ; Membrane Potentials ; Molecular Sequence Data ; Oocytes ; PC12 Cells ; Patch-Clamp Techniques ; *RNA Editing ; Rats ; Rats, Wistar ; Receptors, AMPA/*genetics/*metabolism ; Recombinant Proteins/metabolism ; Xenopus
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  • 62
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-02-18
    Description: Molecular chaperones of the Hsp70 type transiently sequester unfolded segments of proteins and promote their correct folding. Target peptides were labeled with an environmentally sensitive fluorophore so that their binding to the molecular chaperone DnaK of Escherichia coli could be followed in real time. The two-step process was characterized by relaxation times of 27 seconds and 200 seconds with 2 microM DnaK and 0.1 microM ligand at 25 degrees C. In the presence of adenosine triphosphate, the formation of the complex was greatly accelerated and appeared to be a single-exponential process with a relaxation time of 0.4 second. The binding-release cycle of DnaK thus occurs in the time range of polypeptide chain elongation and folding and is too fast to be stoichiometrically coupled to the adenosine triphosphatase activity of the chaperone (turnover number, 0.13 per minute at 30 degrees C).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schmid, D -- Baici, A -- Gehring, H -- Christen, P -- New York, N.Y. -- Science. 1994 Feb 18;263(5149):971-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biochemisches Institut, Universitat Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8310296" target="_blank"〉PubMed〈/a〉
    Keywords: 2-Naphthylamine/analogs & derivatives ; Adenosine Triphosphatases/metabolism ; Adenosine Triphosphate/analogs & derivatives/pharmacology ; Amino Acid Sequence ; Aspartate Aminotransferases/metabolism ; Bacterial Proteins/*metabolism ; Binding Sites ; Enzyme Precursors/metabolism ; *Escherichia coli Proteins ; Fluorescent Dyes ; *HSP70 Heat-Shock Proteins ; Heat-Shock Proteins/*metabolism ; Kinetics ; Molecular Sequence Data ; Peptide Fragments/*metabolism
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  • 63
    Publication Date: 1994-08-05
    Description: The high-mobility group protein 14 (HMG-14) is a non-histone chromosomal protein that is preferentially associated with transcriptionally active chromatin. To assess the effect of HMG-14 on transcription by RNA polymerase II, in vivo-assembled chromatin with elevated amounts of HMG-14 was obtained. Here it is shown that HMG-14 enhanced transcription on chromatin templates but not on DNA templates. This protein stimulated the rate of elongation by RNA polymerase II but not the level of initiation of transcription. These findings suggest that the association of HMG-14 with nucleosomes is part of the cellular process involved in the generation of transcriptionally active chromatin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ding, H F -- Rimsky, S -- Batson, S C -- Bustin, M -- Hansen, U -- GM-36667/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Aug 5;265(5173):796-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Molecular Genetics, Dana-Farber Cancer Institute, Boston, MA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8047885" target="_blank"〉PubMed〈/a〉
    Keywords: Chromatin/metabolism ; HeLa Cells ; High Mobility Group Proteins/*physiology ; Humans ; Kinetics ; RNA Polymerase II/*metabolism ; Simian virus 40/genetics ; Templates, Genetic ; Transcription, Genetic/*physiology
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  • 64
    Publication Date: 1994-08-05
    Description: Activation of 2-5A-dependent ribonuclease by 5'-phosphorylated, 2',5'-linked oligoadenylates, known as 2-5A, is one pathway of interferon action. Unaided uptake into HeLa cells of 2-5A linked to an antisense oligonucleotide resulted in the selective ablation of messenger RNA for the double-stranded RNA (dsRNA)-dependent protein kinase PKR. Similarly, purified, recombinant human 2-5A-dependent ribonuclease was induced to selectively cleave PKR messenger RNA. Cells depleted of PKR activity were unresponsive to activation of nuclear factor-kappa B (NF-kappa B) by the dsRNA poly(I):poly(C), which provides direct evidence that PKR is a transducer for the dsRNA signaling of NF-kappa B.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Maran, A -- Maitra, R K -- Kumar, A -- Dong, B -- Xiao, W -- Li, G -- Williams, B R -- Torrence, P F -- Silverman, R H -- AI 28253/AI/NIAID NIH HHS/ -- AI 34039-02/AI/NIAID NIH HHS/ -- CA 44059/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1994 Aug 5;265(5173):789-92.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cancer Biology, Cleveland Clinic Foundation, OH 44195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7914032" target="_blank"〉PubMed〈/a〉
    Keywords: Adenine Nucleotides/chemical synthesis/*pharmacology ; Base Sequence ; Endoribonucleases/metabolism ; Enzyme Activation ; HeLa Cells ; Humans ; Kinetics ; Molecular Sequence Data ; NF-kappa B/*antagonists & inhibitors ; Oligonucleotides, Antisense/chemical synthesis/*pharmacology ; Oligoribonucleotides/chemical synthesis/*pharmacology ; Protein-Serine-Threonine Kinases/*genetics ; RNA, Messenger/drug effects ; Signal Transduction/*drug effects ; eIF-2 Kinase
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  • 65
    Publication Date: 1994-07-29
    Description: The Escherichia coli chaperonins GroEL and GroES facilitate protein folding in an adenosine triphosphate (ATP)-dependent manner. After a single cycle of ATP hydrolysis by the adenosine triphosphatase (ATPase) activity of GroEL, the bi-toroidal GroEL formed a stable asymmetric ternary complex with GroES and nucleotide (bulletlike structures). With each subsequent turnover, ATP was hydrolyzed by one ring of GroEL in a quantized manner, completely releasing the adenosine diphosphate and GroES that were tightly bound to the other ring as a result of the previous turnover. The catalytic cycle involved formation of a symmetric complex (football-like structures) as an intermediate that accumulated before the rate-determining hydrolytic step. After one to two cycles, most of the substrate protein dissociated still in a nonnative state, which is consistent with intermolecular transfer of the substrate protein between toroids of high and low affinity. A unifying model for chaperonin-facilitated protein folding based on successive rounds of binding and release, and partitioning between committed and kinetically trapped intermediates, is proposed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Todd, M J -- Viitanen, P V -- Lorimer, G H -- New York, N.Y. -- Science. 1994 Jul 29;265(5172):659-66.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉E. I. DuPont de Nemours and Company, Central Research and Development Department, Wilmington, DE 19880.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7913555" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphatases/*metabolism ; Bacterial Proteins/*metabolism ; Binding Sites ; Chaperonin 10 ; Chaperonin 60 ; Heat-Shock Proteins/*metabolism ; Kinetics ; Models, Chemical ; *Protein Folding ; Ribulose-Bisphosphate Carboxylase/metabolism
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  • 66
    Publication Date: 1994-09-02
    Description: A beta 1-40, a major component of Alzheimer's disease cerebral amyloid, is present in the cerebrospinal fluid and remains relatively soluble at high concentrations (less than or equal to 3.7 mM). Thus, physiological factors which induce A beta amyloid formation could provide clues to the pathogenesis of the disease. It has been shown that human A beta specifically and saturably binds zinc. Here, concentrations of zinc above 300 nM rapidly destabilized human A beta 1-40 solutions, inducing tinctorial amyloid formation. However, rat A beta 1-40 binds zinc less avidly and is immune to these effects, perhaps explaining the scarcity with which these animals form cerebral A beta amyloid. These data suggest a role for cerebral zinc metabolism in the neuropathogenesis of Alzheimer's disease.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bush, A I -- Pettingell, W H -- Multhaup, G -- d Paradis, M -- Vonsattel, J P -- Gusella, J F -- Beyreuther, K -- Masters, C L -- Tanzi, R E -- R01 AG11899-01/AG/NIA NIH HHS/ -- R01 NS30428-03/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1994 Sep 2;265(5177):1464-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Genetics and Aging, Massachusetts General Hospital, Boston.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8073293" target="_blank"〉PubMed〈/a〉
    Keywords: Alzheimer Disease/etiology/*metabolism ; Amyloid beta-Peptides/chemistry/*metabolism ; Animals ; Brain/metabolism ; Edetic Acid/pharmacology ; Humans ; Kinetics ; Mice ; Peptide Fragments/chemistry/*metabolism ; Rats ; Solubility ; Zinc/*metabolism/pharmacology
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  • 67
    Publication Date: 1994-07-08
    Description: Monoclonal antibodies, induced with a phosphonate diester hapten, catalyzed the coupling of p-nitrophenyl esters of N-acetyl valine, leucine, and phenylalanine with tryptophan amide to form the corresponding dipeptides. All possible stereoisomeric combinations of the ester and amide substrates were coupled at comparable rates. The antibodies did not catalyze the hydrolysis of the dipeptide product nor hydrolysis or racemization of the activated esters. The yields of the dipeptides ranged from 44 to 94 percent. The antibodies were capable of multiple turnovers at rates that exceeded the rate of spontaneous ester hydrolysis. This achievement suggests routes toward creating a small number of antibody catalysts for polypeptide syntheses.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hirschmann, R -- Smith, A B 3rd -- Taylor, C M -- Benkovic, P A -- Taylor, S D -- Yager, K M -- Sprengeler, P A -- Benkovic, S J -- GM-45611/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jul 8;265(5169):234-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Pennsylvania, Philadelphia 19104.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8023141" target="_blank"〉PubMed〈/a〉
    Keywords: Antibodies, Catalytic/*metabolism ; Antibodies, Monoclonal/*metabolism ; Binding Sites, Antibody ; Dipeptides/*biosynthesis ; Esters ; Haptens ; Kinetics ; Leucine/analogs & derivatives/metabolism ; Molecular Conformation ; Phenylalanine/analogs & derivatives/metabolism ; Stereoisomerism ; Tryptophan/analogs & derivatives/metabolism ; Valine/analogs & derivatives/metabolism
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  • 68
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-03-11
    Description: The repair of cyclobutane pyrimidine dimers (CPDs), DNA lesions induced by ultraviolet light, was studied at nucleotide resolution. Human fibroblasts were irradiated with ultraviolet light and allowed to repair. The DNA was enzymatically cleaved at the CPDs, and the induced breaks along the promoter and exon 1 of the PGK1 gene were mapped by ligation-mediated polymerase chain reaction. Repair rates within the nontranscribed strand varied as much as 15-fold, depending on nucleotide position. Preferential repair of the transcribed strand began just downstream of the transcription start site but was most pronounced beginning at nucleotide +140 in exon 1. The promoter contained two slowly repaired regions that coincided with two transcription factor binding sites.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gao, S -- Drouin, R -- Holmquist, G P -- CA54773/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1994 Mar 11;263(5152):1438-40.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Beckman Research Institute of the City of Hope, Department of Biology, Duarte, CA 91010.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8128226" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Cells, Cultured ; *DNA Repair ; Exons ; *Genes ; HeLa Cells ; Humans ; Kinetics ; Phosphoglycerate Kinase/*genetics ; Promoter Regions, Genetic ; Pyrimidine Dimers/*metabolism ; Skin/metabolism/*radiation effects ; Transcription Factors/metabolism ; Transcription, Genetic ; Ultraviolet Rays
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  • 69
    Publication Date: 1994-08-12
    Description: The critical discriminatory event in the activation of T lymphocytes bearing alpha beta T cell receptors (TCRs) is their interaction with a molecular complex consisting of a peptide bound to a major histocompatibility complex (MHC)-encoded class I or class II molecule on the surface of an antigen-presenting cell. The kinetics of binding were measured of a purified TCR to molecular complexes of a purified soluble analog of the murine MHC class I molecule H-2Ld (sH-2Ld) and a synthetic octamer peptide p2CL in a direct, real-time assay based on surface plasmon resonance. The kinetic dissociation rate of the MHC-peptide complex from the TCR was rapid (2.6 x 10(-2) second-1, corresponding to a half-time for dissociation of approximately 27 seconds), and the kinetic association rate was 2.1 x 10(5) M-1 second-1. The equilibrium constant for dissociation was approximately 10(-7) M. These values indicate that TCRs must interact with a multivalent array of MHC-peptide complexes to trigger T cell signaling.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Corr, M -- Slanetz, A E -- Boyd, L F -- Jelonek, M T -- Khilko, S -- al-Ramadi, B K -- Kim, Y S -- Maher, S E -- Bothwell, A L -- Margulies, D H -- New York, N.Y. -- Science. 1994 Aug 12;265(5174):946-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Biology Section, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8052850" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Biosensing Techniques ; H-2 Antigens/*metabolism ; Histocompatibility Antigen H-2D ; Kinetics ; *Major Histocompatibility Complex ; Mice ; Molecular Sequence Data ; Oligopeptides/*metabolism ; Receptors, Antigen, T-Cell, alpha-beta/*metabolism ; Solubility
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  • 70
    Publication Date: 1994-02-04
    Description: Age-specific mortality rates in isogenic populations of the nematode Caenorhabditis elegans increase exponentially throughout life. In genetically heterogeneous populations, age-specific mortality increases exponentially until about 17 days and then remains constant until the last death occurs at about 60 days. This period of constant age-specific mortality results from genetic heterogeneity. Subpopulations differ in mean life-span, but they all exhibit near exponential, albeit different, rates of increase in age-specific mortality. Thus, much of the observed heterogeneity in mortality rates later in life could result from genetic heterogeneity and not from an inherent effect of aging.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brooks, A -- Lithgow, G J -- Johnson, T E -- K04-AG00369/AG/NIA NIH HHS/ -- R01-AG08332/AG/NIA NIH HHS/ -- R01-AG10248/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 1994 Feb 4;263(5147):668-71.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Behavioral Genetics, University of Colorado, Boulder 80309.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8303273" target="_blank"〉PubMed〈/a〉
    Keywords: Aging ; Animals ; Caenorhabditis elegans/genetics/*physiology ; *Genetic Variation ; Kinetics ; Longevity/genetics ; Mortality
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  • 71
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-06-24
    Description: Formation of a short (less than 2.5 angstroms), very strong, low-barrier hydrogen bond in the transition state, or in an enzyme-intermediate complex, can be an important contribution to enzymic catalysis. Formation of such a bond can supply 10 to 20 kilocalories per mole and thus facilitate difficult reactions such as enolization of carboxylate groups. Because low-barrier hydrogen bonds form only when the pKa's (negative logarithm of the acid constant) of the oxygens or nitrogens sharing the hydrogen are similar, a weak hydrogen bond in the enzyme-substrate complex in which the pKa's do not match can become a strong, low-barrier one if the pKa's become matched in the transition state or enzyme-intermediate complex. Several examples of enzymatic reactions that appear to use this principle are presented.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cleland, W W -- Kreevoy, M M -- GM 18938/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Jun 24;264(5167):1887-90.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Enzyme Research, University of Wisconsin, Madison 53705.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8009219" target="_blank"〉PubMed〈/a〉
    Keywords: Aconitate Hydratase/chemistry/metabolism ; Binding Sites ; Carboxypeptidases/chemistry/metabolism ; *Catalysis ; Citrate (si)-Synthase/chemistry/metabolism ; Enzymes/*metabolism ; *Hydrogen Bonding ; Isomerases/chemistry/metabolism ; Kinetics ; Orotidine-5'-Phosphate Decarboxylase/chemistry/metabolism ; Racemases and Epimerases/chemistry/metabolism ; Thermolysin/chemistry/metabolism
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  • 72
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-05-27
    Description: Two major goals for the design of new catalysts are the facilitation of chemical transformations and control of product outcome. An antibody has been induced that efficiently catalyzes a cationic cyclization in which an acyclic olefinic sulfonate ester substrate is converted almost exclusively (98 percent) to a cyclic alcohol. The key to the catalysis of the reaction and the restriction of the product complexity is the use of antibody binding energy to rigidly enforce a concerted mechanism in accord with the design of the hapten. Thus, the ability to direct binding energy allows the experimenter to dictate a reaction mechanism which is an otherwise difficult task in chemistry. New catalysts for cationic cyclization may be of general use in the formation of carbon-carbon and carbon-heteroatom bonds leading to multi-ring molecules including steroids and heterocyclic compounds.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Li, T -- Janda, K D -- Ashley, J A -- Lerner, R A -- GM-43858/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 May 27;264(5163):1289-93.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Scripps Research Institute, Department of Molecular Biology, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8191282" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Catalytic/*chemistry ; Antibodies, Monoclonal/chemistry ; Catalysis ; Cations/*chemistry ; Chromatography, Gas ; Cyclization ; Haptens ; Kinetics ; Mice ; Organosilicon Compounds/*chemistry ; Sulfanilic Acids/*chemistry
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  • 73
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-03-04
    Description: Any RNA, when in a complex with another oligoribonucleotide known as an external guide sequence (EGS), can become a substrate for ribonuclease P. Simulation of evolution in vitro was used to select EGSs that bind tightly to a target substrate messenger RNA and that increase the efficiency of cleavage of the target by human ribonuclease P to a level equal to that achieved with natural substrates. The most efficient EGSs form transfer RNA precursor-like structures with the target RNA, in which the analog of the anticodon stem has been disrupted, an indication that selection for the optimal substrate for ribonuclease P yields an RNA structure different from that of present-day transfer RNA precursors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yuan, Y -- Altman, S -- AI31876/AI/NIAID NIH HHS/ -- GM19422/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Mar 4;263(5151):1269-73.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Yale University, New Haven, CT 06520.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8122108" target="_blank"〉PubMed〈/a〉
    Keywords: Anticodon/chemistry/metabolism ; Base Sequence ; Chloramphenicol O-Acetyltransferase/genetics ; Endoribonucleases/*metabolism ; Humans ; Kinetics ; Magnesium/pharmacology ; Molecular Sequence Data ; Nucleic Acid Conformation ; Oligoribonucleotides/chemistry/*metabolism ; RNA Precursors/chemistry/metabolism ; RNA, Catalytic/*metabolism ; RNA, Guide/chemistry/*metabolism ; RNA, Messenger/chemistry/*metabolism ; RNA, Transfer/chemistry/metabolism ; Ribonuclease P ; Thermodynamics
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  • 74
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-08-12
    Description: The folding pathways of large, highly structured RNA molecules are largely unexplored. Insight into both the kinetics of folding and the presence of intermediates was provided in a study of the Mg(2+)-induced folding of the Tetrahymena ribozyme by hybridization of complementary oligodeoxynucleotide probes. This RNA folds via a complex mechanism involving both Mg(2+)-dependent and Mg(2+)-independent steps. A hierarchical model for the folding pathway is proposed in which formation of one helical domain (P4-P6) precedes that of a second helical domain (P3-P7). The overall rate-limiting step is formation of P3-P7, and takes place with an observed rate constant of 0.72 +/- 0.14 minute-1. The folding mechanism of large RNAs appears similar to that of many multidomain proteins in that formation of independently stable substructures precedes their association into the final conformation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zarrinkar, P P -- Williamson, J R -- New York, N.Y. -- Science. 1994 Aug 12;265(5174):918-24.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8052848" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Introns ; Kinetics ; Magnesium/metabolism/pharmacology ; Models, Chemical ; Molecular Sequence Data ; *Nucleic Acid Conformation ; Nucleic Acid Hybridization ; Oligonucleotide Probes ; RNA, Catalytic/*chemistry/metabolism ; RNA, Protozoan/*chemistry ; Ribonuclease H/metabolism ; Temperature ; Tetrahymena/*genetics
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  • 75
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-04-08
    Description: Editing reactions are essential for the high fidelity of information transfer in processes such as replication, RNA splicing, and protein synthesis. The accuracy of interpretation of the genetic code is enhanced by the editing reactions of aminoacyl transfer RNA (tRNA) synthetases, whereby amino acids are prevented from being attached to the wrong tRNAs. Amino acid discrimination is achieved through sieves that may overlap with or coincide with the amino acid binding site. With the class I Escherichia coli isoleucine tRNA synthetase, which activates isoleucine and occasionally misactivates valine, as an example, a rationally chosen mutant enzyme was constructed that lacks entirely its normal strong ability to distinguish valine from isoleucine by the initial amino acid recognition sieve. The misactivated valine, however, is still eliminated by hydrolytic editing reactions. These data suggest that there is a distinct sieve for editing that is functionally independent of the amino acid binding site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schmidt, E -- Schimmel, P -- GM 15539/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Apr 8;264(5156):265-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8146659" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Binding Sites ; Escherichia coli/enzymology ; Isoleucine/*metabolism ; Isoleucine-tRNA Ligase/chemistry/genetics/*metabolism ; Kinetics ; Mutation ; Protein Structure, Secondary ; *RNA Editing ; RNA, Transfer, Ile/metabolism ; Valine/*metabolism
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  • 76
    Publication Date: 1994-02-25
    Description: Intracellular vesicles destined to fuse with the plasma membrane and secrete their contents must have a mechanism for specifically interacting with the appropriate target membrane. Such a mechanism is now suggested by the demonstration of specific interaction between vesicular proteins and plasma membrane proteins. The vesicle-associated membrane proteins (VAMPs) 1 and 2 specifically bind the acceptor membrane proteins syntaxin 1A and 4 but not syntaxin 2 or 3. The binding site is within amino acids 194 to 267 of syntaxin 1A, and the approximate equilibrium dissociation constants is 4.7 x 10(-6) molar. These data suggest a physical basis for the specificity of intracellular vesicular transport.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Calakos, N -- Bennett, M K -- Peterson, K E -- Scheller, R H -- New York, N.Y. -- Science. 1994 Feb 25;263(5150):1146-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Stanford University Medical Center, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8108733" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Antigens, Surface/*metabolism ; Binding Sites ; Cell Line ; Cell Membrane/metabolism ; Cytoplasm/metabolism ; Haplorhini ; Kinetics ; Membrane Proteins/*metabolism ; Molecular Sequence Data ; Nerve Tissue Proteins/*metabolism ; R-SNARE Proteins ; Recombinant Fusion Proteins/metabolism ; Synaptic Vesicles/*metabolism ; Syntaxin 1
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 77
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1994-02-18
    Description: A change in radical pair recombination rates is one of the few mechanisms by which a magnetic field can interact with a biological system. The kinetic parameter Vmax/Km (where Km is the Michaelis constant) for the coenzyme B12-dependent enzyme ethanolamine ammonia lyase was decreased 25 percent by a static magnetic field near 0.1 tesla (1000 gauss) with unlabeled ethanolamine and decreased 60 percent near 0.15 tesla with perdeuterated ethanolamine. This effect is likely caused by a magnetic field-induced change in intersystem crossing rates between the singlet and triplet spin states in the [cob(II)alamin:5'-deoxyadenosyl radical] spin-correlated radical pair.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Harkins, T T -- Grissom, C B -- ES05728/ES/NIEHS NIH HHS/ -- New York, N.Y. -- Science. 1994 Feb 18;263(5149):958-60.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Utah, Salt Lake City 84112.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8310292" target="_blank"〉PubMed〈/a〉
    Keywords: Deuterium ; Ethanolamine ; Ethanolamine Ammonia-Lyase/*metabolism ; Ethanolamines/metabolism ; Kinetics ; *Magnetics ; Photolysis ; Vitamin B 12/pharmacology
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