Crystal Structure of the Complex Between Mycobacterium Tuberculosis Beta-Ketoacyl-Acyl Carrier Protein Synthase III and Lauroyl Coenzyme A

Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.208 

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Crystal structure of a substrate complex of Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III (FabH) with lauroyl-coenzyme A.

Musayev, F.Sachdeva, S.Scarsdale, J.N.Reynolds, K.A.Wright, H.T.

(2005) J Mol Biol 346: 1313-1321

  • DOI: https://doi.org/10.1016/j.jmb.2004.12.044
  • Primary Citation of Related Structures:  
    1U6E, 1U6S

  • PubMed Abstract: 

    Beta-ketoacyl-acyl carrier protein synthase III (FabH) catalyzes a two step reaction that initiates the pathway of fatty acid biosynthesis in plants and bacteria. In Mycobacterium tuberculosis, FabH catalyzes extension of lauroyl, myristoyl and palmitoyl groups from which cell wall mycolic acids of the bacterium are formed. The first step of the reaction is an acyl group transfer from acyl-coenzyme A to the active-site cysteine of the enzyme; the second step is acyl chain extension by two carbon atoms through Claisen condensation with malonyl-acyl carrier protein. We have previously determined the crystal structure of a type II, dissociated M.tuberculosis FabH, which catalyzes extension of lauroyl, myristoyl and palmitoyl groups. Here we describe the first long-chain Michaelis substrate complex of a FabH, that of lauroyl-coenzyme A with a catalytically disabled Cys-->Ala mutant of M.tuberculosis FabH. An elongated channel extending from the mutated active-site cysteine defines the acyl group binding locus that confers unique acyl substrate specificity on M.tuberculosis FabH. CoA lies in a second channel, bound primarily through interactions of its nucleotide group at the enzyme surface. The apparent weak association of CoA in this complex may play a role in the binding and dissociation of long chain acyl-CoA substrates and products and poses questions pertinent to the mechanism of this enzyme.

  • Organizational Affiliation

    Institute of Structural Biology and Drug Discovery, Department of Medicinal Chemistry, Virginia Commonwealth University, 800 E. Leigh St., Suite 212, Richmond, VA 23219, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
3-oxoacyl-[acyl-carrier-protein] synthase III
A, B
335Mycobacterium tuberculosisMutation(s): 1 
Gene Names: fabH
Find proteins for P9WNG3 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WNG3 
Go to UniProtKB:  P9WNG3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP9WNG3
Sequence Annotations
  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.208 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.57α = 113.25
b = 63.19β = 100.82
c = 55.33γ = 92.66
Software Package:
Software NamePurpose
bioteXdata collection
bioteXdata reduction
bioteXdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-03-22
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Refinement description, Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description
  • Version 1.4: 2021-10-20
    Changes: Database references, Derived calculations
  • Version 1.5: 2023-08-23
    Changes: Data collection, Refinement description