Oxoacyl-ACP reductase of Plasmodium falciparum

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.202 

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Kinetic, Inhibition and Structural Studies on 3-Oxoacyl-Acp Reductase from Plasmodium Falciparum, a Key Enzyme in Fatty Acid Biosynthesis.

Wickramasinghe, S.R.Inglis, K.A.Urch, J.E.Muller, S.Van Aalten, D.M.F.Fairlamb, A.H.

(2006) Biochem J 393: 447

  • DOI: https://doi.org/10.1042/BJ20050832
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Type II fatty acid biosynthesis represents an attractive target for the discovery of new antimalarial drugs. Previous studies have identified malarial ENR (enoyl acyl-carrier-protein reductase, or FabI) as the target for the antiseptic triclosan. In the present paper, we report the biochemical properties and 1.5 A (1 A=0.1 nm) crystal structure of OAR (3-oxoacyl acyl-carrier-protein reductase, or FabG), the second reductive step in fatty acid biosynthesis and its inhibition by hexachlorophene. Under optimal conditions of pH and ionic strength, Plasmodium falciparum OAR displays kinetic properties similar to those of OAR from bacteria or plants. Activity with NADH is <3% of that with NADPH. Fluorescence enhancement studies indicate that NADPH can bind to the free enzyme, consistent with kinetic and product inhibition studies suggesting a steady-state ordered mechanism. The crystal structure reveals a tetramer with a sulphate ion bound in the cofactor-binding site such that the side chains of the catalytic triad of serine, tyrosine and lysine are aligned in an active conformation, as previously observed in the Escherichia coli OAR-NADP+ complex. A cluster of positively charged residues is positioned at the entrance to the active site, consistent with the proposed recognition site for the physiological substrate (3-oxoacyl-acyl-carrier protein) in E. coli OAR. The antibacterial and anthelminthic agent hexachlorophene is a potent inhibitor of OAR (IC50 2.05 microM) displaying non-linear competitive inhibition with respect to NADPH. Hexachlorophene (EC50 6.2 microM) and analogues such as bithionol also have antimalarial activity in vitro, suggesting they might be useful leads for further development.

  • Organizational Affiliation

    Division of Biological Chemistry and Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
3-OXOACYL-(ACYL-CARRIER PROTEIN) REDUCTASE285Plasmodium falciparum 3D7Mutation(s): 0 
Gene Names: PF3D7_0922900
Find proteins for Q8I2S7 (Plasmodium falciparum (isolate 3D7))
Explore Q8I2S7 
Go to UniProtKB:  Q8I2S7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8I2S7
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on SO4

Download Ideal Coordinates CCD File 
O4 S
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.202 
  • Space Group: P 42 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 73.121α = 90
b = 73.121β = 90
c = 100.176γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-10-20
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance