Structure of P-Carbonic Anhydrase from the Red Alga, Porphyridium purpureum

Structure of p-Carbonic Anhydrase from the Red Alga, Porphyridium purpureum 

It has been postulated that there are two distinct groups of p-CAs, differing in their pattern of sequence conservation, active site design, and possibly in their mechanism. The three zinc-bound ligands and the Asp/Arg pair are conserved in every p-CA sequence known. Two sets of sequences are observed for active site residues, viz. in higher plants (Gln-151, Ser-161, Ser-163, Phe-179, Val-184, and Tyr-205) and in 

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