title: Functional role of two interhelical disulfide bonds in human Cox17 protein from a structural perspective.
abstract: Human Cox17 is the mitochondrial copper chaperone responsible for supplying copper ions, through the assistance of Sco1, Sco2, and Cox11, to cytochrome c oxidase, the terminal enzyme of the mitochondrial energy-transducing respiratory chain. It consists of a coiled coil-helix-coiled coil-helix domain stabilized by two disulfide bonds and binds one copper(I) ion through a Cys-Cys motif. Here, the structures and the backbone mobilities of two Cox17 mutated forms with only one interhelical disulfide bond have been analyzed. It appears that the inner disulfide bond (formed by Cys-36 and Cys-45) stabilizes interhelical hydrophobic interactions, providing a structure with essentially the same structural dynamic properties of the mature Cox17 state. On the contrary, the external disulfide bond (formed by Cys-26 and Cys-55) generates a conformationally flexible α-helical protein, indicating that it is not able to stabilize interhelical packing contacts, but is important for structurally organizing the copper-binding site region.
authors.affiliation: Magnetic Resonance Center Centro Risonanze Magnetiche and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Banci
authors.forename: Ivano
authors.initials: I
authors.lastname: Bertini
authors.forename: Chiara
authors.initials: C
authors.lastname: Cefaro
authors.forename: Simone
authors.initials: S
authors.lastname: Ciofi-Baffoni
authors.forename: Angelo
authors.initials: A
authors.lastname: Gallo
mesh_terms: D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D003300:Copper / Q000737:chemistry / Q000378:metabolism; D000079922:Copper Transport Proteins; D004220:Disulfides / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: C491006:COX17 protein, human; D002352:Carrier Proteins; D000079922:Copper Transport Proteins; D004220:Disulfides; D003300:Copper