Mechanism-based inactivator of isocitrate lyases 1 and 2 from Mycobacterium tuberculosis | Academic Article individual record

© 2017, National Academy of Sciences. All rights reserved. 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 Cys 191 . 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 Cys 191 .

author list (cited authors)
Pham, T. V., Murkin, A. S., Moynihan, M. M., Harris, L., Tyler, P. C., Shetty, N., ... Meek, T. D.
publication date
  • Covalent Adduct
  • 2-vinyl Isocitrate
  • Mechanism-based Inactivation
  • Isocitrate Lyase
  • Tuberculosis