3AM5

K316A mutant of Enoyl-ACP Reductase from Plasmodium falciparum (PfENR) in complex with triclosan


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free: 0.207 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.166 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

Effect of substrate binding loop mutations on the structure, kinetics, and inhibition of enoyl acyl carrier protein reductase from plasmodium falciparum

Maity, K.Banerjee, T.Prabakaran, N.Surolia, N.Surolia, A.Suguna, K.

(2011) IUBMB Life 63: 30-41

  • DOI: https://doi.org/10.1002/iub.412
  • Primary Citation of Related Structures:  
    3AM3, 3AM4, 3AM5

  • PubMed Abstract: 

    Enoyl acyl carrier protein reductase (ENR), which catalyzes the final and rate limiting step of fatty acid elongation, has been validated as a potential drug target. Triclosan is known to be an effective inhibitor for this enzyme. We mutated the substrate binding site residue Ala372 of the ENR of Plasmodium falciparum (PfENR) to Methionine and Valine which increased the affinity of the enzyme towards triclosan to almost double, close to that of Escherichia coli ENR (EcENR) which has a Methionine at the structurally similar position of Ala372 of PfENR. Kinetic studies of the mutants of PfENR and the crystal structure analysis of the A372M mutant revealed that a more hydrophobic environment enhances the affinity of the enzyme for the inhibitor. A triclosan derivative showed a threefold increase in the affinity towards the mutants compared to the wild type, due to additional interactions with the A372M mutant as revealed by the crystal structure. The enzyme has a conserved salt bridge which stabilizes the substrate binding loop and appears to be important for the active conformation of the enzyme. We generated a second set of mutants to check this hypothesis. These mutants showed loss of function, except in one case, where the crystal structure showed that the substrate binding loop is stabilized by a water bridge network.


  • Organizational Affiliation

    Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Enoyl-ACP reductase
A, B
329Plasmodium falciparumMutation(s): 1 
Gene Names: fabI
EC: 1.3.1.9
UniProt
Find proteins for Q9BJJ9 (Plasmodium falciparum)
Explore Q9BJJ9 
Go to UniProtKB:  Q9BJJ9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9BJJ9
Sequence Annotations
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  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
TCL BindingDB:  3AM5 Ki: min: 1.90e-3, max: 13.72 (nM) from 11 assay(s)
IC50: min: 49, max: 200 (nM) from 6 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free: 0.207 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.166 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 131.11α = 90
b = 131.11β = 90
c = 82.78γ = 90
Software Package:
Software NamePurpose
MAR345dtbdata collection
PHASERphasing
REFMACrefinement
MOSFLMdata reduction
SCALAdata 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: 2011-03-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description