PDBsum entry 3e3i

Go to PDB code: 
protein ligands metals Protein-protein interface(s) links
Lyase PDB id
Jmol PyMol
Protein chains
(+ 6 more) 208 a.a. *
SO4 ×13
BCT ×11
_ZN ×12
Waters ×604
* Residue conservation analysis
PDB id:
Name: Lyase
Title: H. Influenzae beta-carbonic anhydrase, variant g41a with 100 bicarbonate
Structure: Carbonic anhydrase 2. Chain: a, b, c, d, e, f, g, h, i, j, k, l. Synonym: carbonate dehydratase 2. Beta carbonic anhydrase. Engineered: yes. Mutation: yes
Source: Haemophilus influenzae. Organism_taxid: 727. Gene: can, hi1301. Expressed in: escherichia coli. Expression_system_taxid: 562.
2.00Å     R-factor:   0.203     R-free:   0.236
Authors: R.S.Rowlett,H.Failing
Key ref: R.S.Rowlett et al. (2010). Evidence for a bicarbonate "escort" site in Haemophilus influenzae beta-carbonic anhydrase . Biochemistry, 49, 3640-3647. PubMed id: 20359198
07-Aug-08     Release date:   18-Aug-09    
Go to PROCHECK summary

Protein chains
Pfam   ArchSchema ?
P45148  (CAN_HAEIN) -  Carbonic anhydrase 2
229 a.a.
208 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 1 residue position (black cross)

 Enzyme reactions 
   Enzyme class: E.C.  - Carbonic anhydrase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: H2CO3 = CO2 + H2O
Bound ligand (Het Group name = BCT)
corresponds exactly
= 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     cellular_component   1 term 
  Biological process     carbon utilization   1 term 
  Biochemical function     lyase activity     4 terms  


    Added reference    
Biochemistry 49:3640-3647 (2010)
PubMed id: 20359198  
Evidence for a bicarbonate "escort" site in Haemophilus influenzae beta-carbonic anhydrase .
R.S.Rowlett, K.M.Hoffmann, H.Failing, M.M.Mysliwiec, D.Samardzic.
The Haemophilus influenzae beta-carbonic anhydrase (HICA) allosteric site variants V47A and G41A were overexpressed and purified to homogeneity. These variants have k(cat)/K(m) values similar to that of the wild-type enzyme and exhibit a similar dramatic decrease in catalytic activity at pH <8.0. However, both HICA-G41A and -V47A were serendipitously found to bind sulfate ion or bicarbonate ion near pairs of Glu50 and Arg64 residues located on the dimerization interface. In the case of HICA-V47A, bicarbonate ions simultaneously bind to both the dimerization interface and the allosteric sites. For HICA-G41A, two of 12 chains in the asymmetric unit bind bicarbonate ion exclusively at the dimerization interface, while the remaining 10 chains bind bicarbonate ion exclusively at the allosteric site. We propose that the new anion binding site along the dimerization interface of HICA is an "escort" site that represents an intermediate along the ingress and egress route of bicarbonate ion to and from the allosteric binding site, respectively. The structural evidence for sulfate binding at the escort site suggests that the mechanism of sulfate activation of HICA is the result of sulfate ion competing for bicarbonate at the escort site, preventing passage of bicarbonate from the bulk solution to its allosteric site.

Literature references that cite this PDB file's key reference

  PubMed id Reference
20659325 L.Syrjänen, M.Tolvanen, M.Hilvo, A.Olatubosun, A.Innocenti, A.Scozzafava, J.Leppiniemi, B.Niederhauser, V.P.Hytönen, T.A.Gorr, S.Parkkila, and C.T.Supuran (2010).
Characterization of the first beta-class carbonic anhydrase from an arthropod (Drosophila melanogaster) and phylogenetic analysis of beta-class carbonic anhydrases in invertebrates.
  BMC Biochem, 11, 28.  
The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time.