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PDBsum entry 3e2x

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protein ligands metals Protein-protein interface(s) links
Lyase PDB id
3e2x
Jmol
Contents
Protein chains
182 a.a. *
Ligands
SO4 ×5
Metals
_ZN ×2
* Residue conservation analysis
PDB id:
3e2x
Name: Lyase
Title: H. Influenzae beta-carbonic anhydrase, variant v47a
Structure: Carbonic anhydrase 2. Chain: a, b. Synonym: carbonate dehydratase 2. Engineered: yes. Mutation: yes
Source: Haemophilus influenzae. Organism_taxid: 727. Gene: can, hi1301. Expressed in: escherichia coli. Expression_system_taxid: 562.
Resolution:
2.55Å     R-factor:   0.214     R-free:   0.283
Authors: R.S.Rowlett,J.Lee
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
Date:
06-Aug-08     Release date:   18-Aug-09    
PROCHECK
Go to PROCHECK summary
 Headers
 References

Protein chains
Pfam   ArchSchema ?
P45148  (CAN_HAEIN) -  Carbonic anhydrase 2
Seq:
Struc:
229 a.a.
182 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.4.2.1.1  - Carbonate dehydratase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: H2CO3 = CO2 + H2O
H(2)CO(3)
= 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     metabolic process   2 terms 
  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.
 
  ABSTRACT  
 
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.