Department of Biology, College of Arts and Sciences, Indiana State University, Terre Haute, IN, 47809, USA.
Biometals. 2022 Apr;35(2):187-213. doi: 10.1007/s10534-022-00373-w. Epub 2022 Feb 22.
Zn ions are essential in many physiological processes, including enzyme catalysis, protein structural stabilization, and the regulation of many proteins. The affinities of proteins for Zn ions span several orders of magnitude, with catalytic Zn ions generally held more tightly than structural or regulatory ones. Metal carrier proteins, most of which are not specific for Zn, bind these ions with a broad range of affinities that overlap those of catalytic, structural, and regulatory Zn ions and are thought to be responsible for distributing the metal through most cells, tissues, and fluid compartments. While little is known about how many proteins obtain or release these ions, there is now considerable experimental evidence suggesting that metal carrier proteins may be responsible for transferring metals to and from some Zn-dependent proteins, thus serving as a major regulatory factor for them. In this review, the biological roles of Zn and structures of Zn binding sites are examined, and experimental evidence demonstrating the direct participation of metal carrier proteins in enzyme regulation is discussed. Mechanisms of metal ion transfer are also offered, and the potential physiological significance of this phenomenon is explored.
锌离子在许多生理过程中都是必不可少的，包括酶催化、蛋白质结构稳定和许多蛋白质的调节。蛋白质与锌离子的亲和力跨越几个数量级，催化锌离子通常比结构或调节锌离子结合得更紧密。大多数非特异性结合锌的金属载体蛋白与这些离子具有广泛的亲和力，与催化、结构和调节锌离子的亲和力重叠，被认为负责将金属分配到大多数细胞、组织和体液隔室中。虽然对于有多少种蛋白质获得或释放这些离子知之甚少，但现在有相当多的实验证据表明，金属载体蛋白可能负责将金属从一些依赖锌的蛋白质中转移出来，从而成为它们的主要调节因子。在这篇综述中，检查了锌的生物学作用和锌结合位点的结构，并讨论了实验证据表明金属载体蛋白直接参与酶调节。还提供了金属离子转移的机制，并探讨了这种现象的潜在生理意义。
