Activation studies with amino acids and amines of a β-carbonic anhydrase from Mammaliicoccus (Staphylococcus) sciuri previously annotated as Staphylococcus aureus (SauBCA) carbonic anhydrase

A beta-carbonic anhydrase (CA, EC 4.2.1.1) previously annotated to be present in the genome of Staphylococcus aureus, SauBCA, has been shown to belong to another pathogenic bacterium, Mammaliicoccus (Staphylococcus) sciuri. This enzyme, MscCA, has been investigated for its activation with a series of natural and synthetic amino acid and amines, comparing the results with those obtained for the ortholog enzyme from Escherichia coli, EcoCA beta. The best MscCA activators were D-His, L- and D-DOPA, 4-(2-aminoethyl)-morpholine and L-Asn, which showed K(A)s of 0.12 - 0.89 mu M. The least efficient activators were D-Tyr and L-Gln (K(A)s of 13.9 - 28.6 mu M). The enzyme was also also inhibited by anions and sulphonamides, as described earlier. Endogenous CA activators may play a role in bacterial virulence and colonisation of the host which makes this research topic of great interest.