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α-Methylene-β-Lactone Probe for Measuring Live-Cell Reactions of Small Molecules

preprint
revised on 11.04.2020 and posted on 13.04.2020 by Lei Wang, Louis Riel, Bekim Bajrami, Bin Deng, Amy Howell, Xudong Yao
The novel use of the α-methylene-β-lactone (MeLac) moiety as a warhead of multiple electrophilic sites is reported. In this study, we demonstrate that a MeLac-alkyne is a competent covalent probe and reacts with diverse proteins in live cells. Proteomics analysis of affinity-enriched samples identifies probe-reacted proteins, resolves their modified peptides/residues, and thus characterizes probe-protein reactions. Unique methods are developed to evaluate confidence in the identification of the reacted proteins and modified peptides. Tandem mass spectra of the peptides reveal that MeLac reacts with nucleophilic cysteine, serine, lysine, threonine, and tyrosine residues, through either Michael addition or acyl addition. A peptide-centric proteomics platform, using MeLac-alkyne as the measurement probe, successfully analyzes the Orlistat selectivity in live HT-29 cells. MeLac is a versatile warhead demonstrating enormous potential to expedite the development of covalent probes and inhibitors in interrogating protein (re)activity. MeLac-empowered platforms in chemical proteomics are widely adaptable for measuring the live-cell action of reactive molecules.

History

Email Address of Submitting Author

x.yao@Uconn.edu

Institution

University of Connecticut

Country

United States

ORCID For Submitting Author

0000-0001-9432-5065

Declaration of Conflict of Interest

no conflict of interest

Version Notes

Ver2.0/Modifications of Figures 1 and 2

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