A New Coral Carbonic Anhydrase in Stylophora pistillata
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Scleractinian corals are of particular interest due to their ability to establish an intracellular mutualistic symbiosis with phototrophic dinoflagellates and to deposit high rates of calcium carbonate in their skeleton. Carbonic anhydrases have been shown to play a crucial role in both processes. In this study, we report the molecular cloning and characterization of a novel α-CA in the coral Stylophora pistillata. This enzyme shares homologies with the human isoform CA II and is referred to as STPCA-2. STPCA-2 is 35.2 kDa and possesses all key amino acids for catalytic activity. With a ratio between catalytic and Michaelis constants (kcat/Km) of 8.3.107 M−1 s−1 is considered as highly active. Owing to its intracellular localisation in the oral endoderm and in the aboral tissue, we propose that STPCA-2 is involved in pH regulation and/or inorganic carbon delivery to symbiont and calcification.
KeywordsScleractinian corals Carbonic anhydrase Symbiosis Calcification Intracelullar pH
We are grateful to Nathalie Techer for her technical help and to Dominique Desgré for coral maintenance.
This study was conducted as part of the Centre Scientifique de Monaco Research Programme, supported by the Government of the Principality of Monaco. Anthony Bertucci was supported by a fellowship from the Scientific Centre of Monaco.
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