Structure of A-type Ketoreductases from Modular Polyketide Synthase

Experimental Data Snapshot

  • Resolution: 1.48 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.215 

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Structural and Functional Analysis of A-Type Ketoreductases from the Amphotericin Modular Polyketide Synthase.

Zheng, J.Taylor, C.A.Piasecki, S.K.Keatinge-Clay, A.T.

(2010) Structure 18: 913-922

  • DOI: https://doi.org/10.1016/j.str.2010.04.015
  • Primary Citation of Related Structures:  
    3MJC, 3MJE, 3MJS, 3MJT, 3MJV

  • PubMed Abstract: 

    Complex polyketides are characterized by multiple chiral centers harboring hydroxyl and alkyl substituents. To investigate the mechanisms by which these stereocenters are set, several high-resolution structures of the ketoreductase (KR) domain from the second module of the amphotericin modular polyketide synthase (PKS) were solved. This first structural analysis of an A-type KR helps reveal how these KRs direct polyketide intermediates into their active sites from the side opposite that used by B-type KRs, resulting in a beta-hydroxyl group of opposite stereochemistry. A comparison of structures obtained in the absence and presence of ligands reveals an induced fit mechanism that is important for catalysis. Activity assays of mutants of KRs from the first and second modules of the amphotericin PKS reveal the relative contributions of several active site residues toward catalysis and stereocontrol. Together, these results highlight the possibility of region-specific modification of polyketides through active site engineering of KRs.

  • Organizational Affiliation

    Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, TX 78712-0165, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
496Streptomyces nodosusMutation(s): 0 
Gene Names: amphB
Find proteins for Q93NW7 (Streptomyces nodosus)
Explore Q93NW7 
Go to UniProtKB:  Q93NW7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ93NW7
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on GOL

Download Ideal Coordinates CCD File 
C3 H8 O3
Experimental Data & Validation

Experimental Data

  • Resolution: 1.48 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.215 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.474α = 72.79
b = 63.746β = 67.3
c = 71.551γ = 89.82
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-08-18
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description