2Q2X

Crystal Structure of the ECH2 decarboxylase domain of CurF from Lyngbya majuscula


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Crystal structure of the ECH2 catalytic domain of CurF from Lyngbya majuscula. Insights into a decarboxylase involved in polyketide chain beta-branching.

Geders, T.W.Gu, L.Mowers, J.C.Liu, H.Gerwick, W.H.Hakansson, K.Sherman, D.H.Smith, J.L.

(2007) J Biol Chem 282: 35954-35963

  • DOI: https://doi.org/10.1074/jbc.M703921200
  • Primary Citation of Related Structures:  
    2Q2X, 2Q34, 2Q35

  • PubMed Abstract: 

    Curacin A is a mixed polyketide/nonribosomal peptide possessing anti-mitotic and anti-proliferative activity. In the biosynthesis of curacin A, the N-terminal domain of the CurF multifunctional protein catalyzes decarboxylation of 3-methylglutaconyl-acyl carrier protein (ACP) to 3-methylcrotonyl-ACP, the postulated precursor of the cyclopropane ring of curacin A. This decarboxylase is encoded within an "HCS cassette" that is used by several other polyketide biosynthetic systems to generate chemical diversity by introduction of a beta-branch functional group to the natural product. The crystal structure of the CurF N-terminal ECH(2) domain establishes that the protein is a crotonase superfamily member. Ala(78) and Gly(118) form an oxyanion hole in the active site that includes only three polar side chains as potential catalytic residues. Site-directed mutagenesis and a biochemical assay established critical functions for His(240) and Lys(86), whereas Tyr(82) was nonessential. A decarboxylation mechanism is proposed in which His(240) serves to stabilize the substrate carboxylate and Lys(86) donates a proton to C-4 of the acyl-ACP enolate intermediate to form the Delta(2) unsaturated isopentenoyl-ACP product. The CurF ECH(2) domain showed a 20-fold selectivity for ACP-over CoA-linked substrates. Specificity for ACP-linked substrates has not been reported for any other crotonase superfamily decarboxylase. Tyr(73) may select against CoA-linked substrates by blocking a contact of Arg(38) with the CoA adenosine 5'-phosphate.


  • Organizational Affiliation

    Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CurF243Moorena producens 19LMutation(s): 4 
Gene Names: curF
UniProt
Find proteins for Q6DNE7 (Lyngbya majuscula)
Explore Q6DNE7 
Go to UniProtKB:  Q6DNE7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ6DNE7
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
MSE
Query on MSE
A
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 
  • Space Group: P 3 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 105.433α = 90
b = 105.433β = 90
c = 46.314γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
SOLVEphasing
RESOLVEphasing
REFMACrefinement
PDB_EXTRACTdata extraction
Blu-Icedata collection
HKL-2000data reduction

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-10-09
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Derived calculations, Source and taxonomy, Version format compliance
  • Version 1.2: 2017-10-18
    Changes: Refinement description