The crystal structure of the terminal R domain from the myxalamid PKS-NRPS biosynthetic pathway

Experimental Data Snapshot

  • Resolution: 1.84 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.176 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


Comprehensive Structural and Biochemical Analysis of the Terminal Myxalamid Reductase Domain for the Engineered Production of Primary Alcohols.

Barajas, J.F.Phelan, R.M.Schaub, A.J.Kliewer, J.T.Kelly, P.J.Jackson, D.R.Luo, R.Keasling, J.D.Tsai, S.C.

(2015) Chem Biol 22: 1018-1029

  • DOI: https://doi.org/10.1016/j.chembiol.2015.06.022
  • Primary Citation of Related Structures:  
    4U7W, 4W4T

  • PubMed Abstract: 

    The terminal reductase (R) domain from the non-ribosomal peptide synthetase (NRPS) module MxaA in Stigmatella aurantiaca Sga15 catalyzes a non-processive four-electron reduction to produce the myxalamide family of secondary metabolites. Despite widespread use in nature, a lack of structural and mechanistic information concerning reductive release from polyketide synthase (PKS) and NRPS assembly lines principally limits our ability to redesign R domains with altered or improved activity. Here we report crystal structures for MxaA R, both in the absence and, for the first time, in the presence of the NADPH cofactor. Molecular dynamics simulations were employed to provide a deeper understanding of this domain and further identify residues critical for structural integrity, substrate binding, and catalysis. Aggregate computational and structural findings provided a basis for mechanistic investigations and, in the process, delivered a rationally altered variant with improved activity toward highly reduced substrates.

  • Organizational Affiliation

    Joint Bioenergy Institute, 5885 Hollis Street, Emeryville, CA 94608, USA; QB3 Institute, University of California, Berkeley, Berkeley, CA 94270, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
420Stigmatella aurantiacaMutation(s): 0 
Gene Names: mxaA
Find proteins for Q93TX2 (Stigmatella aurantiaca)
Explore Q93TX2 
Go to UniProtKB:  Q93TX2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ93TX2
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B
Experimental Data & Validation

Experimental Data

  • Resolution: 1.84 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.176 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 50.838α = 90
b = 159.304β = 108.88
c = 54.897γ = 90
Software Package:
Software NamePurpose
HKL-2000data scaling
Cootmodel building

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 States5R01GM100305-03
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United States5F31GM100738-02

Revision History  (Full details and data files)

  • Version 1.0: 2015-08-12
    Type: Initial release
  • Version 1.1: 2015-09-02
    Changes: Database references
  • Version 1.2: 2017-09-13
    Changes: Author supporting evidence, Database references, Derived calculations
  • Version 1.3: 2019-12-25
    Changes: Author supporting evidence