Abstract Presented here are the results of a study characterizing the selective metal chelating performance of the alternative metal binding (amb) peptide: acetyl-His1-Cys2-Gly3-Pro4-His5-Cys6-OH, and eight ambs with systematic modifications to His, Cys, and carboxyl C-terminus metal chelating sites. The results show that from the divalent metal ions of zinc, nickel, cobalt, magnesium and calcium, the ambs most extensively formed complexes with zinc and nickel. The ambs, which retained both Cys2 and Cys6 in their primary structure, exhibited the greatest formation of zinc complexes. The replacement of His1 and His5 residues with two additional Cys with the amidation of the C-terminus also increased the zinc chelation at pH 7.0. Density functional theory indicated that these modifications might be disrupting the hydrogen bonding between the His-Cys and carboxylate terminus making the 4Cys more available for chelation. Nickel chelation was generally lower than zinc because of competition from the Cys to form disulfide bonds in the presence of nickel. The two ambs that formed the highest number of nickel complexes both included the amidated C-termini and either 4Cys or 2Cys-2His. Comparison with recent published results of six heptapeptide ambs, which have the same primary structures, but with the inclusion of Tyr5 before the final two residues, indicates the inclusion of the Tyr5 residue increases the zinc chelation at pH 7.0 from 25%, of total observed species, to 70%. These types of studies may pave the way to discoveries of new therapeutics suitable as enzyme inhibitors or chelators for diseases associated with metal homeostasis misbalances, or as new peptide tags for recombinant protein purification.

中文翻译：

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使用电喷雾电离的一系列六肽对 Zn(II) 和 Ni(II) 的 pH 依赖性螯合研究 – 离子迁移率 – 质谱法

摘要 这里介绍了一项研究的结果，该研究表征了替代金属结合 (amb) 肽的选择性金属螯合性能：乙酰基-His1-Cys2-Gly3-Pro4-His5-Cys6-OH 和 8 个对 His 进行系统修饰的 ambs， Cys 和羧基 C 端金属螯合位点。结果表明，从锌、镍、钴、镁和钙的二价金属离子中，Ambs最广泛地与锌和镍形成络合物。在其一级结构中保留 Cys2 和 Cys6 的 ambs 表现出最大的锌配合物形成。用两个额外的 Cys 替换 His1 和 His5 残基以及 C 末端的酰胺化也增加了 pH 7.0 时的锌螯合。密度泛函理论表明，这些修饰可能会破坏 His-Cys 和羧酸盐末端之间的氢键，使 4Cys 更易于螯合。由于在镍存在下 Cys 竞争形成二硫键，因此镍螯合通常低于锌。形成最多镍配合物的两个 ambs 均包括酰胺化的 C-末端和 4Cys 或 2Cys-2His。与具有相同一级结构但在最后两个残基之前包含 Tyr5 的六个七肽 amb 最近发表的结果的比较表明，Tyr5 残基的包含将 pH 7.0 下的锌螯合从观察到的总数的 25% 增加种，达到 70%。