title: Unbound position II in MXCXXC metallochaperone model peptides impacts metal binding mode and reactivity: Distinct similarities to whole proteins.
abstract: The effect of position II in the binding sequence of copper metallochaperones, which varies between Thr and His, was investigated through structural analysis and affinity and oxidation kinetic studies of model peptides. A first Cys-Cu(I)-Cys model obtained for the His peptide at acidic and neutral pH, correlated with higher affinity and more rapid oxidation of its complex; in contrast, the Thr peptide with the Cys-Cu(I)-Met coordination under neutral conditions demonstrated weaker and pH dependent binding. Studies with human antioxidant protein 1 (Atox1) and three of its mutants where S residues were replaced with Ala suggested that (a) the binding affinity is influenced more by the binding sequence than by the protein fold (b) pH may play a role in binding reactivity, and (c) mutating the Met impacted the affinity and oxidation rate more drastically than did mutating one of the Cys, supporting its important role in protein function. Position II thus plays a dominant role in metal binding and transport.
authors.affiliation: Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
authors.forename: Michal S
authors.initials: MS
authors.lastname: Shoshan
authors.affiliation: Wolfson Centre for Applied Structural Biology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
authors.forename: Noa
authors.initials: N
authors.lastname: Dekel
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa 02106, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Goch
authors.affiliation: Wolfson Centre for Applied Structural Biology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
authors.forename: Deborah E
authors.initials: DE
authors.lastname: Shalev
authors.affiliation: Wolfson Centre for Applied Structural Biology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
authors.forename: Tsafi
authors.initials: T
authors.lastname: Danieli
authors.affiliation: Wolfson Centre for Applied Structural Biology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
authors.forename: Mario
authors.initials: M
authors.lastname: Lebendiker
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa 02106, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Bal
authors.affiliation: Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel. Electronic address: edit.tshuva@mail.huji.ac.il.
authors.forename: Edit Y
authors.initials: EY
authors.lastname: Tshuva
mesh_terms: D003300:Copper / Q000737:chemistry*; D000079922:Copper Transport Proteins; D006801:Humans; D056511:Metallochaperones / Q000737:chemistry*; D008956:Models, Chemical; D018832:Molecular Chaperones / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*
chemical_list: C474500:ATOX1 protein, human; D000079922:Copper Transport Proteins; D056511:Metallochaperones; D018832:Molecular Chaperones; D010455:Peptides; D003300:Copper
keywords: Atox1; Cu; Metalloproteins; NMR; Peptides