Carbonic anhydrase (CA) is a zinc-containing enzyme that catalyzes the reversible hydration of CO2 to HCO3-. In eukaryotes, the enzyme plays a role in various physiological functions, including interconversion between CO2 and HCO3- in intermediary metabolism, facilitated diffusion of CO2, pH homeostasis and ion transport. The structure of bovine carbonic anhydrase II (BCA II) has been determined by molecular replacement and refined to 1.95 A resolution by simulated-annealing and individual B-factor refinement. The final R factor for the BCA II structure was 19.4%. BCA II has a C-terminal knot structure similar to that observed in human CA II. It contains one zinc ion in the active site coordinated to three histidines and one putative water molecule in a tetrahedral geometry. The structure of BCA II reveals a probable alternative proton-wire pathway that differs from that of HCA II.
Structure of bovine carbonic anhydrase II at 1.95 A resolution.,Saito R, Sato T, Ikai A, Tanaka N Acta Crystallogr D Biol Crystallogr. 2004 Apr;60(Pt 4):792-5. Epub 2004, Mar 23. PMID:15039588
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↑ Saito R, Sato T, Ikai A, Tanaka N. Structure of bovine carbonic anhydrase II at 1.95 A resolution. Acta Crystallogr D Biol Crystallogr. 2004 Apr;60(Pt 4):792-5. Epub 2004, Mar 23. PMID:15039588 doi:10.1107/S0907444904003166