Human carbonic anhydrase in complex with CO2

Experimental Data Snapshot

  • Resolution: 1.56 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.153 
  • R-Value Observed: 0.156 

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This is version 1.2 of the entry. See complete history


Structural Study of X-Ray Induced Activation of Carbonic Anhydrase.

Sjoblom, B.Polentarutti, M.Djinovic-Carugo, K.

(2009) Proc Natl Acad Sci U S A 106: 10609

  • DOI: https://doi.org/10.1073/pnas.0904184106
  • Primary Citation of Related Structures:  
    2VVA, 2VVB

  • PubMed Abstract: 

    Carbonic anhydrase, a zinc metalloenzyme, catalyzes the reversible hydration of carbon dioxide to bicarbonate. It is involved in processes connected with acid-base homeostasis, respiration, and photosynthesis. More than 100 distinct human carbonic anhydrase II (HCAII) 3D structures have been generated in last 3 decades [Liljas A, et al. (1972) Nat New Biol 235:131-137], but a structure of an HCAII in complex with CO(2) or HCO(3)(-) has remained elusive. Here, we report previously undescribed structures of HCAII:CO(2) and HCAII:HCO(3)(-) complexes, together with a 3D molecular film of the enzymatic reaction observed successively in the same crystal after extended exposure to X-ray. We demonstrate that the unexpected enzyme activation was caused in an X-ray dose-dependent manner. Although X-ray damage to macromolecular samples has long been recognized [Ravelli RB, Garman EF (2006) Curr Opin Struct Biol 16:624-629], the detailed structural analysis reports on X-ray-driven reactions have been very rare in literature to date. Here, we report on enzyme activation and the associated chemical reaction in a crystal at 100 K. We propose mechanisms based on water photoradiolysis and/or electron radiolysis as the main cause of enzyme activation.

  • Organizational Affiliation

    Department for Structural and Computational Biology, Max F Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, A-1030 Vienna, Austria.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CARBONIC ANHYDRASE 2A [auth X]260Homo sapiensMutation(s): 0 
Gene Names: CA2
EC: (PDB Primary Data), (UniProt)
UniProt & NIH Common Fund Data Resources
Find proteins for P00918 (Homo sapiens)
Explore P00918 
Go to UniProtKB:  P00918
PHAROS:  P00918
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00918
Sequence Annotations
  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
SO4 BindingDB:  2VVA Ki: min: 8.90e+7, max: 3.00e+8 (nM) from 4 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.56 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.153 
  • R-Value Observed: 0.156 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.589α = 90
b = 41.577β = 104.84
c = 72.636γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-07-14
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance