Assignment of Disulfide-Linked Peptides Using Automatic a1 Ion Recognition

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• 作者：Sheng Yu Huang ; Chien Hsien Wen ; Ding Tzai Li ; Jue Liang Hsu ; Chinpan Chen ; Fong Ku Shi ; Yueh Yi Lin
• 刊名：Analytical Chemistry
• 出版年：2008
• 出版时间：December 1, 2008
• 年：2008
• 卷：80
• 期：23
• 页码：9135-9140
• 全文大小：371K
• 年卷期：v.80,no.23(December 1, 2008)
• ISSN：1520-6882

文摘

We present a novel approach for the assignment of peptides containing disulfide linkages. Dimethyl labeling is introduced to generate labeled peptides which exhibit enhanced a₁ ion signals during MS/MS fragmentation. For disulfide-linked peptides, multiple a₁ ions can be observed due to multiple N-termini. This distinct feature allows sieving out the disulfide-linked peptides; meanwhile, the N-terminal amino acids can be identified. With such information, the number of possible peptide combinations involved in a disulfide bond dramatically narrows down. Furthermore, we developed a computational algorithm to perform target a₁ ion screening followed by molecular weight matching of cysteine-containing peptides with specific amino acids at the N-termini. Once the protein sequence and the peak list from a LC−MS/MS survey scan of labeled peptides are imported, the identities of disulfide-linked peptides can be readily obtained. The presented approach is simple and straightforward, offering a valuable tool for protein structural characterization.