The structure, kinetics and interactions of the β-carboxysomal β-carbonic anhydrase, CcaA.

CcaA is a β-carbonic anhydrase (CA) that is a component of the carboxysomes of a subset of β-cyanobacteria. This protein, which has a characteristic C-terminal extension of unknown function, is recruited to the carboxysome via interactions with CcmM, which is itself a γ-CA homolog with enzymatic activity in many, but not all cyanobacteria. We have determined the structure of CcaA from Synechocystis sp.