title: Contribution of individual histidines to prion protein copper binding.
abstract: The prion protein is well-established as a copper binding protein. The N-terminus of the protein contains an octameric repeat region with each of the four repeats containing a histidine. The N-terminus has two additional histidines distal to the repeat region that has been commonly known as the fifth site. While binding of copper by the protein has been extensively studied, the contribution of each histidine to copper binding in the full-length protein has not. Here we used a battery of mutants of the recombinant mouse prion protein to assess copper binding with both isothermal titration calorimetry and cyclic voltammetry. The findings indicate that there is extensive cooperativity between different binding sites in the protein. The two highest-affinity binding events occur at the fifth site and at the octameric repeat region. However, the first binding is that to the octameric repeat region. Subsequent binding events after the two initial binding events have lower affinities within the octameric repeat region.
authors: Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK.
authors: Paul
authors: P
authors: Davies
authors: Patrick C
authors: PC
authors: McHugh
authors: Victoria J
authors: VJ
authors: Hammond
authors: Frank
authors: F
authors: Marken
authors: David R
authors: DR
authors: Brown
mesh_terms: D000465:Algorithms; D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D002151:Calorimetry; D003300:Copper / Q000737:chemistry*; D055664:Electrochemical Techniques; D006639:Histidine / Q000737:chemistry*; D051379:Mice; D050505:Mutant Proteins / Q000737:chemistry; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D000072002:Prion Proteins; D011328:Prions / Q000737:chemistry* / Q000235:genetics; D011485:Protein Binding; D055550:Protein Stability; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D050505:Mutant Proteins; D000072002:Prion Proteins; D011328:Prions; C512657:Prnp protein, mouse; D011994:Recombinant Proteins; D006639:Histidine; D003300:Copper