1I6P

CRYSTAL STRUCTURE OF E. COLI BETA CARBONIC ANHYDRASE (ECCA)

Summary for 1I6P

• Entry DOI: 10.2210/pdb1i6p/pdb
• Related: 1I6O
• Descriptor: CARBONIC ANHYDRASE, ZINC ION (3 entities in total)
• Functional Keywords: carbonic anhydrase, metalloenzyme, zinc coordination, ph-dependent activity, mad phasing, lyase
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 25196.19

Authors

Cronk, J.D.,Endrizzi, J.A.,Cronk, M.R.,O'Neill, J.W.,Zhang, K.Y.J. (deposition date: 2001-03-02, release date: 2001-05-09, Last modification date: 2023-08-09)

Primary citation

Cronk, J.D.,Endrizzi, J.A.,Cronk, M.R.,O'neill, J.W.,Zhang, K.Y.
Crystal structure of E. coli beta-carbonic anhydrase, an enzyme with an unusual pH-dependent activity.
Protein Sci., 10:911-922, 2001

PubMed Abstract: 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.

PubMed: 11316870
DOI: 10.1110/ps.46301

Experimental method

X-RAY DIFFRACTION (2 Å)