Li Sujun, Dabir Aditi, Misal Santosh A, Tang Haixu, Radivojac Predrag, Reilly James P
School of Informatics and Computing, Indiana University , Bloomington, Indiana 47405, United States.
Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States.
J Proteome Res. 2016 Oct 7;15(10):3656-3665. doi: 10.1021/acs.jproteome.6b00468. Epub 2016 Sep 27.
Peptide amidination labeling using S-methyl thioacetimidate (SMTA) is investigated in an attempt to increase the number and types of peptides that can be detected in a bottom-up proteomics experiment. This derivatization method affects the basicity of lysine residues and is shown here to significantly impact the idiosyncracies of peptide fragmentation and peptide detectability. The unique and highly reproducible fragmentation properties of SMTA-labeled peptides, such as the strong propensity for forming b fragment ions, can be further exploited to modify the scoring of peptide-spectrum pairs and improve peptide identification. To this end, we have developed a supervised postprocessing algorithm to exploit these characteristics of peptides labeled by SMTA. Our experiments show that although the overall number of identifications are similar, the SMTA modification enabled the detection of 16-26% peptides not previously observed in comparable CID/HCD tandem mass spectrometry experiments without SMTA labeling.
使用S-甲基硫代乙脒（SMTA）进行肽脒化标记的研究，旨在增加在自下而上的蛋白质组学实验中可检测到的肽的数量和类型。这种衍生化方法会影响赖氨酸残基的碱性，在此显示它会显著影响肽片段化的特性和肽的可检测性。SMTA标记肽独特且高度可重复的片段化特性，例如形成b离子碎片的强烈倾向，可以进一步用于修改肽-谱对的评分并改善肽的鉴定。为此，我们开发了一种监督后处理算法，以利用SMTA标记肽的这些特性。我们的实验表明，尽管鉴定的总数相似，但SMTA修饰能够检测到在没有SMTA标记的可比CID/HCD串联质谱实验中以前未观察到的16%-26%的肽。
