Download MendeleySeparate Entrance and Exit Portals for Ligand Traffic in Mycobacterium tuberculosis FabH
Sachdeva, S., Musayev, F.N., Alhamadsheh, M.M., Scarsdale, J.N., Wright, H.T., Reynolds, K.A.(2008) Chem Biol 15: 402-412
- PubMed: 18420147
- DOI: https://doi.org/10.1016/j.chembiol.2008.03.007
- Primary Citation of Related Structures:
2QNX, 2QNY, 2QNZ, 2QO0, 2QO1 - PubMed Abstract:
Mycobacterium tuberculosis FabH initiates type II fatty acid synthase-catalyzed formation of the long chain (C(16)-C(22)) acyl-coenzyme A (CoA) precursors of mycolic acids, which are major constituents of the bacterial cell envelope. Crystal structures of M. tuberculosis FabH (mtFabH) show the substrate binding site to be a buried, extended L-shaped channel with only a single solvent access portal. Entrance of an acyl-CoA substrate through the solvent portal would require energetically unfavorable reptational threading of the substrate to its reactive position. Using a class of FabH inhibitors, we have tested an alternative hypothesis that FabH exists in an "open" form during substrate binding and product release, and a "closed" form in which catalysis and intermediate steps occur. This hypothesis is supported by mass spectrometric analysis of the product profile and crystal structures of complexes of mtFabH with these inhibitors.
Organizational Affiliation:
Department of Chemistry, Portland State University, Portland, OR 97207, USA.
