Carugo Oliviero
Department of Structural and Computational Biology, Max F. Perutz Laboratories, Vienna University, Vienna, Austria.
Department of Chemistry, University of Pavia, Pavia, Italy.
BMC Struct Biol. 2014 Sep 23;14:19. doi: 10.1186/s12900-014-0019-8.
Despite the chloride anion is involved in fundamental biological processes, its interactions with proteins are little known. In particular, we lack a systematic survey of its coordination spheres.
The analysis of a non-redundant set (pairwise sequence identity < 30%) of 1739 high resolution (<2 Å) crystal structures that contain at least one chloride anion shows that the first coordination spheres of the chlorides are essentially constituted by hydrogen bond donors. Amongst the side-chains positively charged, arginine interacts with chlorides much more frequently than lysine. Although the most common coordination number is 4, the coordination stereochemistry is closer to the expected geometry when the coordination number is 5, suggesting that this is the coordination number towards which the chlorides tend when they interact with proteins.
The results of these analyses are useful in interpreting, describing, and validating new protein crystal structures that contain chloride anions.
尽管氯离子参与基本的生物过程，但其与蛋白质的相互作用却鲜为人知。特别是，我们缺乏对其配位球的系统研究。
对1739个至少包含一个氯离子的高分辨率（<2 Å）晶体结构的非冗余集（成对序列同一性<30%）的分析表明，氯离子的第一配位球主要由氢键供体构成。在带正电荷的侧链中，精氨酸与氯离子的相互作用比赖氨酸更频繁。虽然最常见的配位数是4，但当配位数为5时，配位立体化学更接近预期几何形状，这表明这是氯离子与蛋白质相互作用时倾向的配位数。
这些分析结果有助于解释、描述和验证包含氯离子的新蛋白质晶体结构。
