Abstract：
Although S-nitrosylation of cysteines is a common protein posttranslational modification, little is known about its three-dimensional structural features. This paper describes a systematic survey of the data available in the Protein Data Bank. Several interesting observations could be made. (1) As a result of radiation damage, S-nitrosylated cysteines (Snc) are frequently reduced, at least partially. (2) S-nitrosylation may be a protection against irreversible thiol oxidation; because the NO group of Snc is relatively accessible to the solvent, it may act as a cork to protect the sulfur atoms of cysteines from oxidation by molecular oxygen to sulfenic, sulfinic, and sulfonic acid; moreover, Snc are frequently found at the start or end of helices and strands and this might shield secondary structural elements from unfolding.
摘要：
尽管半胱氨酸的S-亚硝基化是一种常见的蛋白质翻译后修饰,对其三维结构特征知之甚少。本文介绍了对蛋白质数据库中可用数据的系统调查。可以提出几个有趣的意见。（1）由于辐射损伤，S-亚硝基化半胱氨酸（Snc）经常被还原，至少部分。（2）S-亚硝基化可能是防止不可逆硫醇氧化的保护；因为Snc的NO基团相对容易进入溶剂，它可以充当软木，保护半胱氨酸的硫原子不被分子氧氧化成亚硫，亚磺酸,和磺酸；此外，Snc通常在螺旋和股线的开始或结束时发现，这可能会阻止次要结构元件展开。
