Structure of the thermostable alpha-Carbonic Anydrase from Thiomicrospira crunogena XCL-2 gammaproteobacterium

Experimental Data Snapshot

  • Resolution: 2.60 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.171 
  • R-Value Observed: 0.175 

Starting Model: experimental
View more details

wwPDB Validation   3D Report Full Report

This is version 1.6 of the entry. See complete history


Structural and biophysical characterization of the alpha-carbonic anhydrase from the gammaproteobacterium Thiomicrospira crunogena XCL-2: insights into engineering thermostable enzymes for CO2 sequestration.

Diaz-Torres, N.A.Mahon, B.P.Boone, C.D.Pinard, M.A.Tu, C.Ng, R.Agbandje-McKenna, M.Silverman, D.Scott, K.McKenna, R.

(2015) Acta Crystallogr D Biol Crystallogr 71: 1745-1756

  • DOI: https://doi.org/10.1107/S1399004715012183
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Biocatalytic CO2 sequestration to reduce greenhouse-gas emissions from industrial processes is an active area of research. Carbonic anhydrases (CAs) are attractive enzymes for this process. However, the most active CAs display limited thermal and pH stability, making them less than ideal. As a result, there is an ongoing effort to engineer and/or find a thermostable CA to fulfill these needs. Here, the kinetic and thermal characterization is presented of an α-CA recently discovered in the mesophilic hydrothermal vent-isolate extremophile Thiomicrospira crunogena XCL-2 (TcruCA), which has a significantly higher thermostability compared with human CA II (melting temperature of 71.9°C versus 59.5°C, respectively) but with a tenfold decrease in the catalytic efficiency. The X-ray crystallographic structure of the dimeric TcruCA shows that it has a highly conserved yet compact structure compared with other α-CAs. In addition, TcruCA contains an intramolecular disulfide bond that stabilizes the enzyme. These features are thought to contribute significantly to the thermostability and pH stability of the enzyme and may be exploited to engineer α-CAs for applications in industrial CO2 sequestration.

  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Carbonic anhydrase, alpha family
A, B, C, D
233Hydrogenovibrio crunogenus XCL-2Mutation(s): 0 
Gene Names: Tcr_1545
Find proteins for Q31FD6 (Hydrogenovibrio crunogenus (strain DSM 25203 / XCL-2))
Explore Q31FD6 
Go to UniProtKB:  Q31FD6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ31FD6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.60 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.171 
  • R-Value Observed: 0.175 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 127.059α = 90
b = 102.228β = 127.26
c = 105.021γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
PDB_EXTRACTdata extraction
HKL-2000data scaling
HKL-2000data reduction

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM25154

Revision History  (Full details and data files)

  • Version 1.0: 2015-07-29
    Type: Initial release
  • Version 1.1: 2015-08-12
    Changes: Database references
  • Version 1.2: 2015-08-26
    Changes: Database references
  • Version 1.3: 2017-08-09
    Changes: Database references, Derived calculations
  • Version 1.4: 2017-09-27
    Changes: Author supporting evidence
  • Version 1.5: 2019-12-25
    Changes: Author supporting evidence
  • Version 1.6: 2023-09-27
    Changes: Data collection, Database references, Derived calculations, Refinement description