2QNX image
Entry Detail
PDB ID:
2QNX
Keywords:
Title:
Crystal structure of the complex between the mycobacterium beta-ketoacyl-acyl carrier protein synthase III (FABH) and 11-[(decyloxycarbonyl)dithio]-undecanoic acid
Biological Source:
Host Organism:
PDB Version:
Deposition Date:
2007-07-19
Release Date:
2008-05-06
Method Details:
Experimental Method:
Resolution:
2.70 Å
R-Value Free:
0.25
R-Value Work:
0.20
R-Value Observed:
0.21
Space Group:
C 2 2 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:3-oxoacyl-[acyl-carrier-protein] synthase 3
Chain IDs:A, B
Chain Length:335
Number of Molecules:2
Biological Source:Mycobacterium tuberculosis
Primary Citation
Separate Entrance and Exit Portals for Ligand Traffic in Mycobacterium tuberculosis FabH
Chem.Biol. 15 402 412 (2008)
PMID: 18420147 DOI: 10.1016/j.chembiol.2008.03.007

Abstact

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.

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Primary Citation of related structures