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Cooperative binding
About: Cooperative binding is a research topic. Over the lifetime, 2771 publications have been published within this topic receiving 118964 citations.
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01 Jan 1990TL;DR: Allosteric membrane proteins are studied as indicators of allosteric equilibrium on spin state and coordination of the haem iron and of feedback inhibition without change of quaternary structure in E. Coli repressors.
Abstract: Preface 1. Introduction 2. Haemoglobin: Dependence of allosteric equilibrium on spin state and coordination of the haem iron 3. Haemocyanin: Dependence of allosteric equilibrium on coordination and valency of a binuclear copper complex 4. Haemerythrin: Cooperativity in a binuclear iron complex 5. Glycogen phosphorylase: Control of glycolysis 6. Phosphofructokinase: Further control of glycolysis 7. Feedback inhibition of a biosynthetic pathway: Aspartate Transcarbamoylase 8. Control of nitrogen metabolism: Glutamine synthetase 9. Cooperativity and feedback inhibition without change of quaternary structure: The "trp" and "met" repressors of E. Coli 10. Immunoglobulins: Cooperative binding to multivalent antigens 11. Allosteric membrane proteins.
548 citations
TL;DR: The authors' working model for the structure of the PrP complex shows the histidine residues in successive octarepeats bridged between two copper ions, with both the Nepsilon2 and Ndelta1 imidazole nitrogen of each histidine residue coordinated and the remaining coordination sites occupied by a backbone amide nitrogen and a water molecule.
Abstract: Evidence is growing to support a functional role for the prion protein (PrP) in copper metabolism. Copper ions appear to bind to the protein in a highly conserved octapeptide repeat region (sequence PHGGGWGQ) near the N terminus. To delineate the site and mode of binding of Cu(II) to the PrP, the copper-binding properties of peptides of varying lengths corresponding to 2-, 3-, and 4-octarepeat sequences have been probed by using various spectroscopic techniques. A two-octarepeat peptide binds a single Cu(II) ion with Kd ≈ 6 μM whereas a four-octarepeat peptide cooperatively binds four Cu(II) ions. Circular dichroism spectra indicate a distinctive structuring of the octarepeat region on Cu(II) binding. Visible absorption, visible circular dichroism, and electron spin resonance spectra suggest that the coordination sphere of the copper is identical for 2, 3, or 4 octarepeats, consisting of a square-planar geometry with three nitrogen ligands and one oxygen ligand. Consistent with the pH dependence of Cu(II) binding, proton NMR spectroscopy indicates that the histidine residues in each octarepeat are coordinated to the Cu(II) ion. Our working model for the structure of the complex shows the histidine residues in successive octarepeats bridged between two copper ions, with both the Nɛ2 and Nδ1 imidazole nitrogen of each histidine residue coordinated and the remaining coordination sites occupied by a backbone amide nitrogen and a water molecule. This arrangement accounts for the cooperative nature of complex formation and for the apparent evolutionary requirement for four octarepeats in the PrP.
514 citations
TL;DR: Insights from computational studies of affinities of ligands binding to proteins are reviewed to elucidate how motions and ensembles and alternative conformers and the entropies and forces that cannot be seen in single molecular structures also contribute to binding affinITIES.
510 citations
01 Jan 1999
TL;DR: In this article, the copper-binding properties of peptides of varying lengths corresponding to 2-, 3-, and 4-octarepeat sequences have been probed by using various spectroscopic techniques.
Abstract: Evidence is growing to support a functional role for the prion protein (PrP) in copper metabolism. Copper ions appear to bind to the protein in a highly conserved octapeptide repeat region (sequence PHGGGWGQ) near the N terminus. To delineate the site and mode of binding of Cu(II) to the PrP, the copper-binding properties of peptides of varying lengths corresponding to 2-, 3-, and 4-octarepeat sequences have been probed by using various spectroscopic techniques. A two-octarepeat peptide binds a single Cu(II) ion with Kd ' 6 mM whereas a four-octarepeat peptide coopera- tively binds four Cu(II) ions. Circular dichroism spectra indicate a distinctive structuring of the octarepeat region on Cu(II) binding. Visible absorption, visible circular dichroism, and electron spin resonance spectra suggest that the coordi- nation sphere of the copper is identical for 2, 3, or 4 octare- peats, consisting of a square-planar geometry with three nitrogen ligands and one oxygen ligand. Consistent with the pH dependence of Cu(II) binding, proton NMR spectroscopy indicates that the histidine residues in each octarepeat are coordinated to the Cu(II) ion. Our working model for the structure of the complex shows the histidine residues in successive octarepeats bridged between two copper ions, with both the N«2 and Nd1 imidazole nitrogen of each histidine residue coordinated and the remaining coordination sites occupied by a backbone amide nitrogen and a water molecule. This arrangement accounts for the cooperative nature of complex formation and for the apparent evolutionary require- ment for four octarepeats in the PrP.
497 citations
TL;DR: The crystal structure of an active, hexameric fragment of the gene 4 helicase from bacteriophage T7 reveals how subunit contacts stabilize the hexamer, and suggests a mechanism for DNA translocation.
487 citations