Mechanism-based inactivator of isocitrate lyases 1 and 2 from Mycobacterium tuberculosis Academic Article uri icon

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.

altmetric score

  • 5.75

author list (cited authors)

  • Pham, T. V., Murkin, A. S., Moynihan, M. M., Harris, L., Tyler, P. C., Shetty, N., ... Meek, T. D.

citation count

  • 15

publication date

  • July 2017