1HZP

Crystal Structure of the Myobacterium Tuberculosis Beta-Ketoacyl-Acyl Carrier Protein Synthase III


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.222 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Crystal structure of the Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III

Scarsdale, J.N.Kazanina, G.He, X.Reynolds, K.A.Wright, H.T.

(2001) J.Biol.Chem. 276: 20516-20522

  • DOI: 10.1074/jbc.M010762200
  • Also Cited By: 2QNX, 2QNY, 2QNZ, 2QO0, 2QO1, 2QX1

  • PubMed Abstract: 
  • Mycolic acids (alpha-alkyl-beta-hydroxy long chain fatty acids) cover the surface of mycobacteria, and inhibition of their biosynthesis is an established mechanism of action for several key front-line anti-tuberculosis drugs. In mycobacteria, long ch ...

    Mycolic acids (alpha-alkyl-beta-hydroxy long chain fatty acids) cover the surface of mycobacteria, and inhibition of their biosynthesis is an established mechanism of action for several key front-line anti-tuberculosis drugs. In mycobacteria, long chain acyl-CoA products (C(14)-C(26)) generated by a type I fatty-acid synthase can be used directly for the alpha-branch of mycolic acid or can be extended by a type II fatty-acid synthase to make the meromycolic acid (C(50)-C(56)))-derived component. An unusual Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein (ACP) synthase III (mtFabH) has been identified, purified, and shown to catalyze a Claisen-type condensation between long chain acyl-CoA substrates such as myristoyl-CoA (C(14)) and malonyl-ACP. This enzyme, presumed to play a key role in initiating meromycolic acid biosynthesis, was crystallized, and its structure was determined at 2.1-A resolution. The mtFabH homodimer is closely similar in topology and active-site structure to Escherichia coli FabH (ecFabH), with a CoA/malonyl-ACP-binding channel leading from the enzyme surface to the buried active-site cysteine residue. Unlike ecFabH, mtFabH contains a second hydrophobic channel leading from the active site. In the ecFabH structure, this channel is blocked by a phenylalanine residue, which constrains specificity to acetyl-CoA, whereas in mtFabH, this residue is a threonine, which permits binding of longer acyl chains. This same channel in mtFabH is capped by an alpha-helix formed adjacent to a 4-amino acid sequence insertion, which limits bound acyl chain length to 16 carbons. These observations offer a molecular basis for understanding the unusual substrate specificity of mtFabH and its probable role in regulating the biosynthesis of the two different length acyl chains required for generation of mycolic acids. This mtFabH presents a new target for structure-based design of novel antimycobacterial agents.


    Organizational Affiliation

    Department of Biochemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia 23219, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
3-OXOACYL-[ACYL-CARRIER-PROTEIN] SYNTHASE III
A, B
335Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)Gene Names: fabH
EC: 2.3.1.180
Find proteins for P9WNG3 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Go to UniProtKB:  P9WNG3
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download SDF File 
Download CCD File 
A, B
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
DAO
Query on DAO

Download SDF File 
Download CCD File 
A
LAURIC ACID
C12 H24 O2
POULHZVOKOAJMA-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.222 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 64.082α = 90.00
b = 54.779β = 90.30
c = 89.152γ = 90.00
Software Package:
Software NamePurpose
bioteXdata reduction
bioteXdata collection
SCALEPACKdata scaling
CNSphasing
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-06-13
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance
  • Version 1.3: 2017-10-04
    Type: Refinement description