PDBsum entry 4hba

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Lyase PDB id
Protein chain
257 a.a.
GOL ×2
Waters ×203
PDB id:
Name: Lyase
Title: Structural and catalytic characterization of a thermal and a variant of human carbonic anhydrase ii containing an engine disulfide bond
Structure: Carbonic anhydrase 2. Chain: a. Synonym: carbonate dehydratase ii, carbonic anhydrasE C, ca carbonic anhydrase ii, ca-ii. Engineered: yes. Mutation: yes
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: ca2. Expressed in: escherichia coli. Expression_system_taxid: 562
1.76Å     R-factor:   0.152     R-free:   0.189
Authors: C.D.Boone,A.Habibzadegan,R.Mckenna
Key ref: C.D.Boone et al. (2013). Structural and catalytic characterization of a thermally stable and acid-stable variant of human carbonic anhydrase II containing an engineered disulfide bond. Acta Crystallogr D Biol Crystallogr, 69, 1414-1422. PubMed id: 23897465 DOI: 10.1107/S0907444913008743
27-Sep-12     Release date:   31-Jul-13    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
P00918  (CAH2_HUMAN) -  Carbonic anhydrase 2
260 a.a.
257 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 3 residue positions (black crosses)

 Enzyme reactions 
   Enzyme class: E.C.  - Carbonate dehydratase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: H2CO3 = CO2 + H2O
= CO(2)
+ H(2)O
      Cofactor: Zn(2+)
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     extracellular space   11 terms 
  Biological process     angiotensin-mediated signaling pathway   22 terms 
  Biochemical function     protein binding     5 terms  


    Added reference    
DOI no: 10.1107/S0907444913008743 Acta Crystallogr D Biol Crystallogr 69:1414-1422 (2013)
PubMed id: 23897465  
Structural and catalytic characterization of a thermally stable and acid-stable variant of human carbonic anhydrase II containing an engineered disulfide bond.
C.D.Boone, A.Habibzadegan, C.Tu, D.N.Silverman, R.McKenna.
The carbonic anhydrases (CAs) are a family of mostly zinc metalloenzymes that catalyze the reversible hydration of CO2 to bicarbonate and a proton. Recently, there has been industrial interest in utilizing CAs as biocatalysts for carbon sequestration and biofuel production. The conditions used in these processes, however, result in high temperatures and acidic pH. This unfavorable environment results in rapid destabilization and loss of catalytic activity in CAs, ultimately resulting in cost-inefficient high-maintenance operation of the system. In order to negate these detrimental industrial conditions, cysteines at residues 23 (Ala23Cys) and 203 (Leu203Cys) were engineered into a wild-type variant of human CA II (HCAII) containing the mutation Cys206Ser. The X-ray crystallographic structure of the disulfide-containing HCAII (dsHCAII) was solved to 1.77 Å resolution and revealed that successful oxidation of the cysteine bond was achieved while also retaining desirable active-site geometry. Kinetic studies utilizing the measurement of (18)O-labeled CO2 by mass spectrometry revealed that dsHCAII retained high catalytic efficiency, and differential scanning calorimetry showed acid stability and thermal stability that was enhanced by up to 14 K compared with native HCAII. Together, these studies have shown that dsHCAII has properties that could be used in an industrial setting to help to lower costs and improve the overall reaction efficiency.