Unbound position II in MXCXXC metallochaperone model peptides impacts metal binding mode and reactivity: Distinct similarities to whole proteins

Michal S Shoshan; Noa Dekel; Wojciech Goch; Deborah E Shalev; Tsafi Danieli; Mario Lebendiker; Wojciech Bal; Edit Y Tshuva

doi:10.1016/j.jinorgbio.2016.02.016

Unbound position II in MXCXXC metallochaperone model peptides impacts metal binding mode and reactivity: Distinct similarities to whole proteins

J Inorg Biochem. 2016 Jun:159:29-36. doi: 10.1016/j.jinorgbio.2016.02.016. Epub 2016 Feb 12.

Authors

Michal S Shoshan¹, Noa Dekel², Wojciech Goch³, Deborah E Shalev², Tsafi Danieli², Mario Lebendiker², Wojciech Bal³, Edit Y Tshuva⁴

Affiliations

¹ Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
² Wolfson Centre for Applied Structural Biology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
³ Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa 02106, Poland.
⁴ Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel. Electronic address: edit.tshuva@mail.huji.ac.il.

PMID: 26901629
DOI: 10.1016/j.jinorgbio.2016.02.016

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.

Keywords: Atox1; Cu; Metalloproteins; NMR; Peptides.

MeSH terms

Copper / chemistry*
Copper Transport Proteins
Humans
Metallochaperones / chemistry*
Models, Chemical*
Molecular Chaperones / chemistry*
Peptides / chemistry*

Substances

ATOX1 protein, human
Copper Transport Proteins
Metallochaperones
Molecular Chaperones
Peptides
Copper