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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1i6p

E.C. namecarbonate dehydratase
SpeciesEscherichia coli (Bacteria)
E.C. Number (IntEnz) 4.2.1.1
CSA Homologues of 1i6pThere are 25 Homologs
CSA Entries With UniProtID P61517
CSA Entries With EC Number 4.2.1.1
PDBe Entry 1i6p
PDBSum Entry 1i6p
MACiE Entry 1i6p

Literature Report

IntroductionBeta-carbonic anhydrases are found in a variety of higher plants, simple eukaryotes, eubacteria and archaea. they catalyse the interconversion of carbon dioxide and bicarbonate. These are zinc-containing metalloenzymes.
MechansimAfter association of carbon dioxide with the binding site, Asp 44 (activated by binding with zinc and electrostatic interaction with Arg 46) acts as a base to abstract a proton from the water molecule. This yields a nucleophilic hydroxide that binds the zinc which further activates it for nucleophilic attack of the carbon dioxide to generate zinc-bound bicarbonate. Loss of the proton is catalysed by Asp 44 again acting as a base to transfer the proton to the solvent, and the product leaves the active site.
Reaction

Catalytic Sites for 1i6p

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
AspA4444macie:sideChainActs as a base to deprotonate the attacking water nucleophile and the substrate.
ArgA4646macie:sideChainActivates Asp 44.

Literature References

Notes:
Cronk JD
Crystal structure of E. coli beta-carbonic anhydrase, an enzyme with an unusual pH-dependent activity.
Protein Sci 2001 10 911-922
PubMed: 11316870
Mitsuhashi S
X-ray structure of beta-carbonic anhydrase from the red alga, Porphyridium purpureum, reveals a novel catalytic site for CO(2) hydration.
J Biol Chem 2000 275 5521-5526
PubMed: 10681531
Smith KS
Roles of the conserved aspartate and arginine in the catalytic mechanism of an archaeal beta-class carbonic anhydrase.
J Bacteriol 2002 184 4240-4245
PubMed: 12107142
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