Discovery of Cysteine Carboxyalkylations by Real-Time Isotopic Signature Targeted Profiling

• DOI: 10.1021/jacs.4c16183
• Publication Date: 2025-02-21T19:58:41Z
• Authors: Guogeng Jia; Yicheng Liu; Tianyu Feng; Zixuan Zhang; Huan Tang; Fan Yang; Ziyao Tang; Weidi Xiao; Ying Chen; Jinjun Gao; Chu Wang
• Keywords: Shotgun proteomics; Shotgun; Profiling (computer programming)

Data-dependent acquisition (DDA) is widely applied in shotgun proteomics. However, restricted by the scanning speed of mass spectrometry (MS) instruments, it remains challenging for DDA to directly detect peptides with low abundance. Herein, we developed a real-time targeted MS data method, "isoSTAR", which identifies target their unique isotopic signatures during stage full-MS and subjects them MS/MS scans immediately. The method showed dramatic improvement sensitivity identifying abundance compared traditional methods. Using this discovered series carboxyalkylations on cysteines fatty acid metabolism verified modification structures using synthetic peptide standards. We envision that isoSTAR will become powerful versatile tool enhance proteomics applications profiling protein-centric modifications.