title: Cation binding mode of fully oxidised calmodulin explained by the unfolding of the apostate.
abstract: Calmodulin is the most ubiquitous calcium binding protein. The protein is very sensitive to oxidation and this modification has pronounced effects on calmodulin function. In this work, we decided to fully oxidise calmodulin in order to study the consequences on cation binding, domain stability, and alpha helicity. Oxidation of methionines unfolds completely the apostate of the protein, which upon calcium binding recovers the major part of its secondary and tertiary structure. However, the unstructuring of the apostate results in a protein that binds calcium to any site in an independent manner, does not bind magnesium and does not possess auxiliary sites anymore.
authors.affiliation: UMR CNRS 6032, UFR de Pharmacie, 27 Bd Jean Moulin 13385 Cedex 5, Marseilles, France. daniel.lafitte@pharmacie.univ-mrs.fr
authors.forename: Daniel
authors.initials: D
authors.lastname: Lafitte
authors.forename: Philippe O
authors.initials: PO
authors.lastname: Tsvetkov
authors.forename: François
authors.initials: F
authors.lastname: Devred
authors.forename: René
authors.initials: R
authors.lastname: Toci
authors.forename: Frédéric
authors.initials: F
authors.lastname: Barras
authors.forename: Claudette
authors.initials: C
authors.lastname: Briand
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Makarov
authors.forename: Jacques
authors.initials: J
authors.lastname: Haiech
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001059:Apoproteins / Q000737:chemistry / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism*; D002151:Calorimetry; D006358:Hot Temperature; D008274:Magnesium / Q000378:metabolism; D008715:Methionine / Q000737:chemistry; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011485:Protein Binding; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
chemical_list: D001059:Apoproteins; D002147:Calmodulin; D008715:Methionine; D008274:Magnesium; D002118:Calcium