Crystal structure of the trans-acyltransferase polyketide synthase enoyl-isomerase

Experimental Data Snapshot

  • Resolution: 1.73 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.215 

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A Double-Hotdog with a New Trick: Structure and Mechanism of the trans-Acyltransferase Polyketide Synthase Enoyl-isomerase.

Gay, D.C.Spear, P.J.Keatinge-Clay, A.T.

(2014) ACS Chem Biol 9: 2374-2381

  • DOI: https://doi.org/10.1021/cb500459b
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Many polyketide natural products exhibit invaluable medicinal properties, yet much remains to be understood regarding the machinery responsible for their biosynthesis. The recently discovered trans-acyltransferase polyketide synthases employ processing enzymes that catalyze modifications unique from those of the classical cis-acyltransferase polyketide synthases. The enoyl-isomerase domains of these megasynthases shift double bonds and are well-represented by an enzyme that helps forge the triene system within the antibiotic produced by the prototypical bacillaene synthase. This first crystal structure of an enoyl-isomerase, at 1.73 Å resolution, not only revealed relationships between this class of enzymes and dehydratases but also guided an investigation into the mechanism of double bond migration. The catalytic histidine, positioned differently from that of dehydratases, was demonstrated to independently shuttle a proton between the γ- and α-positions of the intermediate. This unprecedented mechanism highlights the catalytic diversity of divergent enzymes within trans-acyltransferase polyketide synthases.

  • Organizational Affiliation

    Department of Molecular Biosciences, University of Texas at Austin , Austin, Texas 78712, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Polyketide synthase PksR290Bacillus subtilis subsp. subtilis str. 168Mutation(s): 0 
Gene Names: pksRBSU17220
EC: 2.3.1
Find proteins for O31784 (Bacillus subtilis (strain 168))
Explore O31784 
Go to UniProtKB:  O31784
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO31784
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.73 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.215 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.821α = 90
b = 68.267β = 90
c = 77.823γ = 90
Software Package:
Software NamePurpose

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM106112

Revision History  (Full details and data files)

  • Version 1.0: 2014-08-20
    Type: Initial release
  • Version 1.1: 2014-10-29
    Changes: Database references
  • Version 1.2: 2017-09-13
    Changes: Author supporting evidence, Derived calculations, Other, Source and taxonomy
  • Version 1.3: 2019-12-25
    Changes: Author supporting evidence
  • Version 1.4: 2023-12-27
    Changes: Data collection, Database references, Refinement description