文章基本信息

标题：Mechanism-based inactivator of isocitrate lyases 1 and 2 from Mycobacterium tuberculosis
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作者：Truc V. Pham ; Andrew S. Murkin ; Margaret M. Moynihan 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2017
卷号：114
期号：29
页码：7617-7622
DOI：10.1073/pnas.1706134114
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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.
关键词：mechanism-based inactivation ; isocitrate lyase ; tuberculosis ; 2-vinyl isocitrate ; covalent adduct