2a8c

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2a8c, resolution 2.30Å ()
Ligands: ,
Gene: can (Haemophilus influenzae)
Activity: Carbonate dehydratase, with EC number 4.2.1.1
Related: 2a8d
Resources: FirstGlance, OCA, PDBsum, RCSB
Coordinates: save as pdb, mmCIF, xml



Contents

Haemophilus influenzae beta-carbonic anhydrase

Publication Abstract from PubMed

The structures of beta class carbonic anhydrases (beta-CAs) determined so far fall into two distinct subclasses based on the observed coordination of the catalytic zinc (Zn2+) ion. The subclass of beta-CAs that coordinate Zn2+ tetrahedrally with four protein-derived ligands is represented by the structures of orthologues from Porphyridium purpureum, Escherichia coli, and Mycobacterium tuberculosis. Here we present the structure of an additional member of that subclass, that from Haemophilus influenzae, as well as detailed kinetic analysis, revealing the correspondence between structural classification and kinetic profile for this subclass. In addition, we identify a unique, noncatalytic binding mode for the substrate bicarbonate that occurs in both the H. influenzae and E. coli enzymes. The kinetic and structural analysis indicates that binding of bicarbonate in this site of the enzyme may modulate its activity by influencing a pH-dependent, cooperative transition between active and inactive forms. We hypothesize that the two structural subclasses of beta-CAs may provide models for the proposed active and inactive forms of the H. influenzae and E. coli enzymes.

Identification of a novel noncatalytic bicarbonate binding site in eubacterial beta-carbonic anhydrase., Cronk JD, Rowlett RS, Zhang KY, Tu C, Endrizzi JA, Lee J, Gareiss PC, Preiss JR, Biochemistry. 2006 Apr 11;45(14):4351-61. PMID:16584170

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

About this Structure

2a8c is a 6 chain structure with sequence from Haemophilus influenzae. Full crystallographic information is available from OCA.

See Also

Reference

  • Cronk JD, Rowlett RS, Zhang KY, Tu C, Endrizzi JA, Lee J, Gareiss PC, Preiss JR. Identification of a novel noncatalytic bicarbonate binding site in eubacterial beta-carbonic anhydrase. Biochemistry. 2006 Apr 11;45(14):4351-61. PMID:16584170 doi:10.1021/bi052272q

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