2a8d | pdb_00002a8d

Haemophilus influenzae beta-carbonic anhydrase complexed with bicarbonate

spinqualitylabelsall models 2a8d, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2a8d is a 6 chain structure with sequence from "bacterium_influenzae"_lehmann_and_neumann_1896 "bacterium influenzae" lehmann and neumann 1896. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: BCT, SO4, ZN Related: 2a8c Gene: can ("Bacterium influenzae" Lehmann and Neumann 1896) Activity: Carbonate dehydratase, with EC number 4.2.1.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. 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. See Also Carbonic anhydrase 3D structures

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