Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
J Biol Inorg Chem. 2010 May;15(4):461-83. doi: 10.1007/s00775-010-0625-2. Epub 2010 Feb 19.
Cu(A) is a binuclear copper center that functions as an electron transfer agent, cycling between a reduced Cu(I)Cu(I) state and an oxidized mixed-valence Cu(+1.5)...Cu(+1.5) state. The copper ions are bridged by two cysteine thiolate ligands and form a copper-copper bond, the first reported of its kind in Nature. Such a "diamond-core" Cu(2)S(Cys)(2) structure allows an unpaired electron to be completely delocalized over the two copper ions and contributes to its highly efficient electron transfer properties. This review provides accounts of how the Cu(A) center was structurally characterized and highlights its salient spectroscopic properties. In the process, it introduces the Cu(A) center in four different systems-native protein systems, soluble protein truncates of native proteins, synthetic models using organic molecules, and biosynthetic models using proteins as ligands-with a greater emphasis on biosynthetic models of Cu(A), especially on new, deeper insights gained from their studies.
Cu(A) 是一个双核铜中心，作为电子转移剂发挥作用，在还原的 Cu(I)Cu(I)态和氧化的混合价态 Cu(+1.5)…Cu(+1.5)态之间循环。两个半胱氨酸硫醇配体桥接铜离子，形成铜-铜键，这是自然界中首次报道的此类键。这种“钻石核心”Cu(2)S(Cys)(2)结构允许未配对的电子完全离域到两个铜离子上，并有助于其高效的电子转移性质。本综述介绍了 Cu(A) 中心的结构特征，并强调了其显著的光谱性质。在此过程中，它介绍了 Cu(A) 中心在四个不同的系统中的情况——天然蛋白系统、天然蛋白的可溶性蛋白截断物、使用有机分子的合成模型以及使用蛋白作为配体的生物合成模型——特别强调了生物合成模型的 Cu(A)，尤其是从这些研究中获得的新的、更深入的见解。
