Shoshan Michal S, Dekel Noa, Goch Wojciech, Shalev Deborah E, Danieli Tsafi, Lebendiker Mario, Bal Wojciech, Tshuva Edit Y
Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
Wolfson Centre for Applied Structural Biology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
J Inorg Biochem. 2016 Jun;159:29-36. doi: 10.1016/j.jinorgbio.2016.02.016. Epub 2016 Feb 12.
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.
通过对模型肽的结构分析、亲和力和氧化动力学研究，探究了铜金属伴侣结合序列中位置II（在苏氨酸和组氨酸之间变化）的作用。在酸性和中性pH条件下，为组氨酸肽获得的首个半胱氨酸-铜（I）-半胱氨酸模型，与其复合物的更高亲和力和更快氧化相关；相比之下，在中性条件下具有半胱氨酸-铜（I）-甲硫氨酸配位的苏氨酸肽表现出较弱且依赖于pH的结合。对人抗氧化蛋白1（Atox1）及其三个将S残基替换为丙氨酸的突变体的研究表明：（a）结合亲和力受结合序列的影响大于蛋白质折叠；（b）pH可能在结合反应性中起作用；（c）甲硫氨酸突变对亲和力和氧化速率的影响比半胱氨酸之一的突变更为显著，支持了其在蛋白质功能中的重要作用。因此，位置II在金属结合和转运中起主导作用。
