| Literature DB >> 28679637 |
Truc V Pham1, Andrew S Murkin2, Margaret M Moynihan2, Lawrence Harris3, Peter C Tyler3, Nishant Shetty1,4, James C Sacchettini1,5, Hsiao-Ling Huang5,6, Thomas D Meek7.
Abstract
Isocitrate lyase (ICL, types 1 and 2) is the first enzyme of the glyoxylate shunt, an essential pathway for Mycobacterium tuberculosis (Mtb) during the persistent phase of human TB infection. Here, we report 2-vinyl-d-isocitrate (2-VIC) as a mechanism-based inactivator of Mtb ICL1 and ICL2. The enzyme-catalyzed retro-aldol cleavage of 2-VIC unmasks a Michael substrate, 2-vinylglyoxylate, which then forms a slowly reversible, covalent adduct with the thiolate form of active-site Cys191 2-VIC displayed kinetic properties consistent with covalent, mechanism-based inactivation of ICL1 and ICL2 with high efficiency (partition ratio, <1). Analysis of a complex of ICL1:2-VIC by electrospray ionization mass spectrometry and X-ray crystallography confirmed the formation of the predicted covalent S-homopyruvoyl adduct of the active-site Cys191.Entities:
Keywords: 2-vinyl isocitrate; covalent adduct; isocitrate lyase; mechanism-based inactivation; tuberculosis
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Year: 2017 PMID： 28679637 PMCID： PMC5530696 DOI： 10.1073/pnas.1706134114
Source DB: PubMed Journal: Proc Natl Acad Sci U S A ISSN： 0027-8424 Impact factor: 11.205