Crystal structure of E. coli beta-carbonic anhydrase, an enzyme with an unusual pH-dependent activity.Cronk, J.D., Endrizzi, J.A., Cronk, M.R., O'neill, J.W., Zhang, K.Y.
(2001) Protein Sci. 10: 911-922
- PubMed: 11316870
- DOI: 10.1110/ps.46301
- Primary Citation of Related Structures:  1I6P
- PubMed Abstract:
- Cloning, crystallization and preliminary characterization of a beta carbonic anhydrase from Escherichia coli
Cronk, J.D.,O'Neill, J.W.,Cronk, M.R.,Endrizzi, J.A.,Zhang, K.Y.J.
(2000) Acta Crystallogr.,Sect.D 52: 1176
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 de ...
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.
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.