Structural profiling of endogenous S-nitrosocysteine residues reveals unique features that accommodate diverse mechanisms for protein S-nitrosylation
Structural profiling of endogenous S-nitrosocysteine residues reveals unique features that accommodate diverse mechanisms for protein S-nitrosylation
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DOI：
10.1073/pnas.1008036107
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发表时间：
2010-09-28
影响因子：
11.1
通讯作者：
Ischiropoulos, Harry
中科院分区：
文献类型：
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作者：
Doulias, Paschalis-Thomas;Greene, Jennifer L.;Ischiropoulos, Harry
S-亚硝基化是蛋白质半胱氨酸残基选择性翻译后修饰形成S-亚硝基半胱氨酸的过程，是一氧化氮影响多种生物学功能的分子机制之一。在这项研究中，独特的基于MS的蛋白质组学方法精确地定位了WT小鼠肝脏中内源性修饰的192种蛋白质中328种肽的S-亚硝基化位点。结构分析表明，S-亚硝基化半胱氨酸残基均匀分布在蛋白质的疏水和亲水区域，平均预测pK（a）为10.01 +/- 2.1。与未修饰的半胱氨酸残基相比，在相同蛋白质中，S-亚硝基化位点在α-螺旋中过多，而在卷曲中过少（χ（2）检验，P < 0.02）。分位数-分位数概率图表明，S-亚硝基半胱氨酸残基的分布偏向于更大的表面可及区域相比，在相同的蛋白质中的未修饰的半胱氨酸残基。70%的S-亚硝基化半胱氨酸残基被带负电荷或带正电荷的氨基酸在6埃距离内包围。半胱氨酸残基在α-螺旋和卷曲中的位置在由带电氨基酸邻接的高度可及表面中意味着由蛋白质-蛋白质或小分子相互作用介导的位点定向S-亚硝基化。此外，13个修饰的半胱氨酸残基与金属配位，15个金属蛋白被内源性修饰，支持金属催化的S-亚硝基化机制。总的来说，肝脏中的内源性S-亚硝基蛋白质组具有适应选择性定点S-亚硝基化的多种机制的结构特征。
S-nitrosylation, the selective posttranslational modification of protein cysteine residues to form S-nitrosocysteine, is one of the molecular mechanisms by which nitric oxide influences diverse biological functions. In this study, unique MS-based proteomic approaches precisely pinpointed the site of S-nitrosylation in 328 peptides in 192 proteins endogenously modified in WT mouse liver. Structural analyses revealed that S-nitrosylated cysteine residues were equally distributed in hydrophobic and hydrophilic areas of proteins with an average predicted pK(a) of 10.01 +/- 2.1. S-nitrosylation sites were over-represented in a-helices and under-represented in coils as compared with unmodified cysteine residues in the same proteins (chi(2) test, P < 0.02). A quantile-quantile probability plot indicated that the distribution of S-nitrosocysteine residues was skewed toward larger surface accessible areas compared with the unmodified cysteine residues in the same proteins. Seventy percent of the S-nitrosylated cysteine residues were surrounded by negatively or positively charged amino acids within a 6-angstrom distance. The location of cysteine residues in a-helices and coils in highly accessible surfaces bordered by charged amino acids implies site directed S-nitrosylation mediated by protein-protein or small molecule interactions. Moreover, 13 modified cysteine residues were coordinated with metals and 15 metalloproteins were endogenously modified supporting metal-catalyzed S-nitrosylation mechanisms. Collectively, the endogenous S-nitrosoproteome in the liver has structural features that accommodate multiple mechanisms for selective site-directed S-nitrosylation.