Thermal-stable carbonic anhydrases: a structural overview.

The potential of carbonic anhydrase (CA) family as target for the drug design of inhibitors with various medicinal chemistry applications has been recognized from long time, whereas the industrial interest in using these enzymes as biocatalysts for carbon dioxide sequestration and biofuel production is only recently emerging. However, an efficient utilization in these processes often requires stable enzymes, able to work in the harsh conditions typical of the CO2 capture process. In this context CAs active at very high temperatures are of extreme interest. In this chapter we have summarized in a comparative manner all existing data on thermostable CAs both isolated by extremophiles and obtained by protein engineering studies. Among the five CA-classes, the biochemical and structural features of thermostable alpha-, beta- and gamma-CAs have been discussed. Data show that so far alpha-CAs isolated from thermophilic organisms are the best candidates to be used in biotechnological processes, even if plenty of work can be still done in this field also with help of protein engineering.