Crystal Structure of the Prolyl Acyl Carrier Protein Oxidase AnaB

Experimental Data Snapshot

  • Resolution: 2.80 Å
  • R-Value Free: 0.219 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.189 

wwPDB Validation   3D Report Full Report

Ligand Structure Quality Assessment 

This is version 1.2 of the entry. See complete history


Structure of the prolyl-acyl carrier protein oxidase involved in the biosynthesis of the cyanotoxin anatoxin-a.

Moncoq, K.Regad, L.Mann, S.Mejean, A.Ploux, O.

(2013) Acta Crystallogr D Biol Crystallogr 69: 2340-2352

  • DOI: https://doi.org/10.1107/S0907444913021859
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Anatoxin-a and homoanatoxin-a are two potent cyanobacterial neurotoxins biosynthesized from L-proline by a short pathway involving polyketide synthases. Proline is first loaded onto AnaD, an acyl carrier protein, and prolyl-AnaD is then oxidized to 1-pyrroline-5-carboxyl-AnaD by a flavoprotein, AnaB. Three polyketide synthases then transform this imine into anatoxin-a or homoanatoxin-a. AnaB was crystallized in its holo form and its three-dimensional structure was determined by X-ray diffraction at 2.8 Å resolution. AnaB is a homotetramer and its fold is very similar to that of the acyl-CoA dehydrogenases (ACADs). The active-site base of AnaB, Glu244, superimposed very well with that of human isovaleryl-CoA dehydrogenase, confirming previous site-directed mutagenesis experiments and mechanistic proposals. The substrate-binding site of AnaB is small and is likely to be fitted for the pyrrolidine ring of proline. However, in contrast to ACADs, which use an electron-transport protein, AnaB uses molecular oxygen as the electron acceptor, as in acyl-CoA oxidases. Calculation of the solvent-accessible surface area around the FAD in AnaB and in several homologues showed that it is significantly larger in AnaB than in its homologues. A protonated histidine near the FAD in AnaB is likely to participate in oxygen activation. Furthermore, an array of water molecules detected in the AnaB structure suggests a possible path for molecular oxygen towards FAD. This is consistent with AnaB being an oxidase rather than a dehydrogenase. The structure of AnaB is the first to be described for a prolyl-ACP oxidase and it will contribute to defining the structural basis responsible for oxygen reactivity in flavoenzymes.

  • Organizational Affiliation

    CNRS, UMR 7099, Institut de Biologie Physico-Chimique, 13 Rue Pierre et Marie Curie, 75005 Paris, France.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Prolyl-ACP dehydrogenase
A, B, C, D, E
A, B, C, D, E, F, G, H
416Kamptonema sp. PCC 6506Mutation(s): 0 
Gene Names: anaBOSCI_4070008
EC: 1.3.99
Find proteins for C4NCB7 (Kamptonema sp. PCC 6506)
Explore C4NCB7 
Go to UniProtKB:  C4NCB7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupC4NCB7
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.80 Å
  • R-Value Free: 0.219 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.189 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 64.442α = 90
b = 191.184β = 98.94
c = 132.492γ = 90
Software Package:
Software NamePurpose
SCALAdata scaling
PDB_EXTRACTdata extraction
MxCuBEdata collection
XDSdata reduction

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-11-27
    Type: Initial release
  • Version 1.1: 2014-01-08
    Changes: Database references
  • Version 1.2: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description