The radical ion chemistry of S-nitrosylated peptides.
The radical ion chemistry of S-nitrosylated peptides.
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S-亚硝基化肽的自由基离子化学。
DOI：
10.1007/s13361-012-0492-x
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发表时间：
2012
影响因子：
3.2
通讯作者：
Jones AW
中科院分区：
文献类型：
--
作者：
Jones AW
研究了一组s -亚硝基肽的自由基化学性质。对NYCGLPGEYWLGNDK、NYCGLPGEYWLGNDR、NYCGLPGERWLGNDR、NACGAPGEKWAGNDK、NYCGLPGEKYLGNDK、nyglpcekwygndk和NYGLPGEKWYGCNDK的双质子化和三质子化离子进行电子俘获解离（ECD）和碰撞诱导解离（CID）。选择的肽序列，可以询问s -亚硝基化位点的影响，碱性氨基酸残基的性质和位置，以及其他氨基酸侧链的性质。ECD质谱主要由一个峰主导，对应于电荷还原前驱体的•NO损失，这可以用改进的犹他-华盛顿机制来解释。在一些肽的ECD中也观察到保留亚硝基修饰的骨干断裂。肽离子结构的分子动力学模拟表明，ECD行为依赖于质子化残基的表面可及性。这些亚硝基化肽的CID导致S-N键的均裂，形成一个长寿命的自由基，损失了•NO。分离出自由基多肽离子，并进行ECD和CID处理。自由基肽离子的ECD与未修饰肽的ECD进行了有趣的比较。主要过程是电子捕获而不进一步解离（ECnoD）。自由基肽离子的CID导致半胱氨酸、亮氨酸和天冬酰胺侧链损失，自由基诱导色氨酸、酪氨酸和天冬酰胺残基上的主链断裂，以及电荷导向的主链断裂。
The radical ion chemistry of a suite ofS-nitrosopeptides has been investigated. Doubly and triply-protonated ions of peptides NYCGLPGEYWLGNDK, NYCGLPGEYWLGNDR, NYCGLPGERWLGNDR, NACGAPGEKWAGNDK, NYCGLPGEKYLGNDK, NYGLPGCEKWYGNDK and NYGLPGEKWYGCNDK were subjected to electron capture dissociation (ECD), and collision-induced dissociation (CID). The peptide sequences were selected such that the effect of the site ofS-nitrosylation, the nature and position of the basic amino acid residues, and the nature of the other amino acid side chains, could be interrogated. The ECD mass spectra were dominated by a peak corresponding to loss of•NO from the charge-reduced precursor, which can be explained by a modified Utah-Washington mechanism. Some backbone fragmentation in which the nitrosyl modification was preserved was also observed in the ECD of some peptides. Molecular dynamics simulations of peptide ion structure suggest that the ECD behavior was dependent on the surface accessibility of the protonated residue. CID of theS-nitrosylated peptides resulted in homolysis of the S–N bond to form a long-lived radical with loss of•NO. The radical peptide ions were isolated and subjected to ECD and CID. ECD of the radical peptide ions provided an interesting comparison to ECD of the unmodified peptides. The dominant process was electron capture without further dissociation (ECnoD). CID of the radical peptide ions resulted in cysteine, leucine, and asparagine side chain losses, and radical-induced backbone fragmentation at tryptophan, tyrosine, and asparagine residues, in addition to charge-directed backbone fragmentation.