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1i6o, resolution 2.20Å ()
Non-Standard Residues:
Gene: YADF (Escherichia coli)
Activity: Carbonate dehydratase, with EC number
Related: 1i6p
Resources: FirstGlance, OCA, PDBsum, RCSB
Coordinates: save as pdb, mmCIF, xml



Publication Abstract from PubMed

Carbonic anhydrases fall into three distinct evolutionary and structural classes: alpha, beta, and gamma. The beta-class carbonic anhydrases (beta-CAs) are widely distributed among higher plants, simple eukaryotes, eubacteria, and archaea. We have determined the crystal structure of ECCA, a beta-CA from Escherichia coli, to a resolution of 2.0 A. In agreement with the structure of the beta-CA from the chloroplast of the red alga Porphyridium purpureum, the active-site zinc in ECCA is tetrahedrally coordinated by the side chains of four conserved residues. These results confirm the observation of a unique pattern of zinc ligation in at least some beta-CAS: The absence of a water molecule in the inner coordination sphere is inconsistent with known mechanisms of CA activity. ECCA activity is highly pH-dependent in the physiological range, and its expression in yeast complements an oxygen-sensitive phenotype displayed by a beta-CA-deletion strain. The structural and biochemical characterizations of ECCA presented here and the comparisons with other beta-CA structures suggest that ECCA can adopt two distinct conformations displaying widely divergent catalytic rates.

Crystal structure of E. coli beta-carbonic anhydrase, an enzyme with an unusual pH-dependent activity., Cronk JD, Endrizzi JA, Cronk MR, O'neill JW, Zhang KY, Protein Sci. 2001 May;10(5):911-22. PMID:11316870

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

About this Structure

1i6o is a 2 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA.

See Also


  • Cronk JD, Endrizzi JA, Cronk MR, O'neill JW, Zhang KY. Crystal structure of E. coli beta-carbonic anhydrase, an enzyme with an unusual pH-dependent activity. Protein Sci. 2001 May;10(5):911-22. PMID:11316870
  • Zhang RG, Dementieva I, Duke N, Collart F, Quaite-Randall E, Alkire R, Dieckman L, Maltsev N, Korolev O, Joachimiak A. Crystal structure of Bacillus subtilis ioli shows endonuclase IV fold with altered Zn binding. Proteins. 2002 Aug 1;48(2):423-6. PMID:12112707 doi:10.1002/prot.10159

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