Characterization of amino acid side chain losses in electron capture dissociation
Characterization of amino acid side chain losses in electron capture dissociation
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DOI：
10.1016/s1044-0305(01)00357-9
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发表时间：
2002-03-01
影响因子：
3.2
通讯作者：
Marshall, AG
中科院分区：
文献类型：
--
作者：
Cooper, HJ;Hudgins, RR;Marshall, AG
我们已经使用电喷雾电离（ESI）傅里叶变换离子回旋共振（FTICR）质谱表征在电子捕获解离（ECD）的10个7- 14-mer肽的氨基酸侧链损失。观察到精氨酸、组氨酸、天冬酰胺或谷氨酰胺、甲硫氨酸和赖氨酸残基的侧链裂解。所有含有精氨酸、组氨酸、天冬酰胺或谷氨酰胺的肽都显示出与该残基相关的损失。观察到双质子化蛙皮素的甲硫氨酸侧链损失。赖氨酸侧链损失，观察到氚质子化的强啡肽A片段1-13，但不是双质子化的离子。精氨酸与甲氧基C-末端基团的接近显著增强了侧链断裂的程度。在所有情况下，与侧链损失相关的碎片离子与主链裂解产生的碎片离子的丰度相当。在一种肽的ECD谱中，主要产物是由于精氨酸侧链内的片段化。我们的研究结果表明，侧链内的裂解应考虑在ECD质谱数据的分析。精氨酸、组氨酸和精氨酸/谷氨酰胺的损失可用于确定它们的存在，如在未知肽的分析中，特别是具有非线性结构的肽。(C)2002年美国质谱学会。
We have used electrospray ionization (ESI) Fourier-transform ion cyclotron resonance (FTICR) mass spectrometry to characterize amino acid side chain losses observed during electron capture dissociation (ECD) of ten 7- to 14-mer peptides. Side-chain cleavages were observed for arginine, histidine, asparagine or glutamine, methionine, and lysine residues. All peptides containing an arginine, histidine, asparagine or glutamine showed the losses associated with that residue. Methionine side-chain loss was observed for doubly-protonated bombesin. Lysine side-chain loss was observed for triply-protonated dynorphin A fragment 1-13 but not for the doubly-protonated ion. The proximity of arginine to a methoxy C-terminal group significantly enhances the extent of side-chain fragmentation. Fragment ions associated with side-chain losses were comparable in abundance to those resulting from backbone cleavage in all cases. In the ECD spectrum of one peptide, the major product was due to fragmentation within an arginine side chain. Our results suggest that cleavages within side chains should be taken into account in analysis of ECD mass spectral data. Losses from arginine, histidine, and asparigine/glutamine can be used to ascertain their presence, as in the analysis of unknown peptides, particularly those with non-linear structures. (C) 2002 American Society for Mass Spectrometry.