Metallothioneins (MTs) are a ubiquitous class of small cysteine-rich metal-binding proteins involved in metal homeostasis and detoxification with highly versatile metal binding properties. Despite the long-standing association of MT with M₃S₃ and M₄S₅ metal clusters, synthetic complexes with these core architectures are exceptionally rare. Here, we demonstrate an approach to synthesizing and characterizing aggregates of group 12 metal ions with monocyclic M₃S₃ cores in acetonitrile solution without the protection of a protein. Multidentate monothiol ligand N,N-bis(2-pyridylmethyl)-2-aminoethanethiol (L1H) provided [Cd₃(L1)₃](ClO₄)₃ (1), the first structurally characterized nonproteinaceous aggregate with a metallothionein-like monocyclic Cd₃S₃ core. In addition, [Zn₃(L1)₃](ClO₄)₃·4CH₃CN (2·4CH₃CN) was characterized by X-ray crystallography. The complex cations of 1 and 2 had comparable structures despite being nonisomorphic. Variable temperature and concentration ¹H NMR were used to investigate aggregation equilibria of 1, 2, and a precipitate with composition “Hg(L1)(ClO₄)” (3). Cryogenic ¹H NMR studies of 3 revealed a J(¹⁹⁹Hg¹H) coupling constant pattern consistent with an aggregate possessing a cyclic core. ESI-MS was used for gas-phase characterization of 1–3, as well as mixed-metal [M₂M′(L1)₃(ClO₄)₂]⁺ ions prepared in situ by pairwise acetonitrile solution combinations of the group 12 complexes of L1. Access to synthetic variants of metallothionein-like group 12 aggregates provides an additional approach to understanding their behavior.

中文翻译：

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同核和异核 12 族金属硫蛋白 B 型簇类似物：合成、结构、1H NMR 和 ESI-MS

金属硫蛋白 (MT) 是一类普遍存在的富含半胱氨酸的小金属结合蛋白，参与金属稳态和解毒，具有高度通用的金属结合特性。_{尽管 MT 与 M 3} S ₃和 M ₄ S ₅金属簇有着长期的联系，但具有这些核心结构的合成配合物非常罕见。_{在这里，我们展示了一种在没有蛋白质保护的情况下在乙腈溶液中合成和表征具有单环 M 3} S ₃核的第 12 族金属离子聚集体的方法。多齿单硫醇配体N , N -双(2-吡啶基甲基)-2-氨基乙硫醇 ( L1H) 提供了 [Cd ₃ ( L1 ) ₃ ](ClO ₄ ) ₃ ( 1 )，这是第一个具有金属硫蛋白样单环 Cd ₃ S ₃核心的结构特征非蛋白质聚集体。此外，对[Zn ₃ ( L1 ) ₃ ](ClO ₄ ) ₃ ·4CH ₃ CN ( 2 ·4CH ₃ CN) 进行了X射线晶体学表征。1和2的复杂阳离子尽管是非同构的，但具有相似的结构。可变温度和浓度¹ H NMR 用于研究1、2和组成为“Hg( L1 )(ClO ₄ )” ( 3 )的沉淀物的聚集平衡。3的低温¹ H NMR 研究表明J ( ¹⁹⁹ Hg ¹ H) 耦合常数模式与具有循环核心的聚集体一致。ESI-MS 用于1 – 3以及混合金属 [M ₂ M'( L1 ) ₃ (ClO ₄ ) ₂ ] ⁺的气相表征离子由L1的第 12 组配合物的成对乙腈溶液组合原位制备。获得类金属硫蛋白第 12 组聚集体的合成变体提供了一种了解其行为的额外方法。