生物信息学分析CysC特异性肽段及质谱验证

CysC specific peptides: bioinformatics analysis and mass spectrometry verification

目的用生物信息学技术分析半胱氨酸蛋白酶抑制剂C(Cys C)的特异性肽段及其性质,并用质谱技术验证预测结果。方法用在线软件工具分析胰蛋白酶水解Cys C产生的肽段和同源性,预测特异性肽段质谱扫描离子化碎片信息;对人工合成的特异性多肽样品进行母离子扫描和子离子扫描,人重组Cys C和血清样品经胰蛋白酶水解后分析质谱,比较分析结果与预测结果。结果选择T3(ALDFAVGEYNK)肽段作为Cys C的特异性肽段,用串联质谱对T3样品[M+2H]^(2+)进行子离子扫描,几乎可发现Skyline软件预测的所有b离子和y离子。人重组Cys C和血清样品经胰蛋白酶水解出的肽段与T3*在同一时间出峰。结论用生物信息学技术快速准确地筛选出了Cys C特异性肽段并准确预测该肽段质谱扫描离子化碎片。

Objective To analyze the specific peptide of cystatin C （CysC） and its characteristics by bioinformatics technology, and verify the predicted results by mass spectromewy. Methods Online software was applied to analyze the physicochemical properties and homology of CysC peptides hydrolyzed by trypsin and predict the associated parameters of ionized fragmentation of specific peptide by mass spectrometry. Precursor ion scan and product ion scan were conducted on the samples of synthetic specific peptide. The recombinant human CysC and serum samples were analyzed by mass spectrometry after trypsin digestion. The results of analysis were compared with the outcomes predicted by bioinfonnatics. Results T3 （ALDFAVGEYNK） was considered as the specific peptide of CysC by software analysis. When selecting[ M ＋2H]2＋ for product ion scan, almost all the y and b ions of fragmentation were observed using tandem mass spectrometry （MS/MS）, showing consistency with Skyline predictions. Moreover, both the peptides from the human recombinant CysC and serum sample following the trypsin digestion were eluted at the same time with the isotope-labeled T3 ＊ under the fixed conditions. Conclusion Bioinformatics technology could be available for picking out the specific peptides of target protein quick- ly and efficiently and predicting the ionized fragmentation precisely by mass spectrometry scanning.