The X-ray crystal structure of the Paramecium bursaria Chlorella virus arginine decarboxylase bound to agmatine

Experimental Data Snapshot

  • Resolution: 1.80 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.219 

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X-ray Structure of Paramecium bursaria Chlorella Virus Arginine Decarboxylase: Insight into the Structural Basis for Substrate Specificity.

Shah, R.Akella, R.Goldsmith, E.J.Phillips, M.A.

(2007) Biochemistry 46: 2831-2841

  • DOI: https://doi.org/10.1021/bi6023447
  • Primary Citation of Related Structures:  
    2NV9, 2NVA

  • PubMed Abstract: 

    The group IV pyridoxal-5'-phosphate (PLP)-dependent decarboxylases belong to the beta/alpha barrel structural family, and include enzymes with substrate specificity for a range of basic amino acids. A unique homolog of this family, the Paramecium bursaria Chlorella virus arginine decarboxylase (cvADC), shares about 40% amino acid sequence identity with the eukaryotic ornithine decarboxylases (ODCs). The X-ray structure of cvADC has been solved to 1.95 and 1.8 A resolution for the free and agmatine (product)-bound enzymes. The global structural differences between cvADC and eukaryotic ODC are minimal (rmsd of 1.2-1.4 A); however, the active site has significant structural rearrangements. The key "specificity element," is identified as the 310-helix that contains and positions substrate-binding residues such as E296 cvADC (D332 in T. brucei ODC). In comparison to the ODC structures, the 310-helix in cvADC is shifted over 2 A away from the PLP cofactor, thus accommodating the larger arginine substrate. Within the context of this conserved fold, the protein is designed to be flexible in the positioning and amino acid sequence of the 310-helix, providing a mechanism to evolve different substrate preferences within the family without large structural rearrangements. Also, in the structure, the "K148-loop" (homologous to the "K169-loop" of ODC) is observed in a closed, substrate-bound conformation for the first time. Apparently the K148 loop is a mobile loop, analogous to those observed in triose phosphate isomerase and tryptophan synthetase. In conjunction with prior structural studies these data predict that this loop adopts different conformations throughout the catalytic cycle, and that loop movement may be kinetically linked to the rate-limiting step of product release.

  • Organizational Affiliation

    Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
arginine decarboxylase, A207R protein
A, B, C, D, E
A, B, C, D, E, F, G, H
372Paramecium bursaria Chlorella virus 1Mutation(s): 0 
Gene Names: A207R
Find proteins for Q84527 (Paramecium bursaria Chlorella virus 1)
Explore Q84527 
Go to UniProtKB:  Q84527
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ84527
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.80 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.219 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 116.206α = 90
b = 117.275β = 90
c = 268.65γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-03-20
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description
  • Version 1.4: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description