Quantitative profiling of PTM stoichiometry by resolvable mass tags

• Published in: RSC chemical biology Vol. 3; no. 11; pp. 132 - 1324
• Main Authors: Chen, Ying, Quan, Baiyi, Li, Yuanpei, Liu, Yuan, Qin, Wei, Wang, Chu
• Format: Journal Article
• Language: English
• Published: RSC 02.11.2022
• Subjects: Chemistry
• ISSN: 2633-0679; 2633-0679
• DOI: 10.1039/d2cb00179a

Post-translational modifications (PTMs) play important roles in modulating the biological functions of proteins. Stoichiometry, which quantifies the modification percentage, is a critical factor for any given PTM. In this work, we developed a chemoproteomic strategy called "STO-MS" to systematically quantify the PTM stoichiometry in complex biological samples. This strategy employs a resolvable mass tag to differentiate proteoforms with different numbers of modifications and utilizes liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) techniques to measure PTM stoichiometry at the proteomic level. As a proof-of-concept, we successfully determined the stoichiometry of 197 proteins modified by 4-hydroxynonenal (HNE), a well-characterized lipid-derived electrophile and biomarker for oxidative stress. Our work expands the toolbox for quantification of PTM stoichiometry and sheds light on understanding the biological significance of PTMs in oxidative stress. Post-translational modifications (PTMs) play important roles in modulating the biological functions of proteins.