Escherichia coli γ -carbonic anhydrase: characterisation and effects of simple aromatic/heterocyclic sulphonamide inhibitors

摘要

Carbonic anhydrases (CAs, EC 4.2.1.1) are ubiquitous metalloenzymes involved in biosynthetic processes, transport, supply, and balance of COsub2/sub/HCOsub3/sub sup-/sup into the cell. In Bacteria, CAs avoid the depletion of the dissolved COsub2/sub/HCOsub3/sub sup-/sup from the cell, providing them to the central metabolism that is compromised without the CA activity. The involvement of CAs in the survival, pathogenicity, and virulence of several bacterial pathogenic species is recent. Here, we report the kinetic properties of the recombinant γ-CA (EcoCAγ) encoded in the genome of Escherichia coli. EcoCAγ is an excellent catalyst for the physiological COsub2/sub hydration reaction to bicarbonate and protons, with a ksubcat/sub of 5.7?×?10sup5/sup?ssup?1/sup and ksubcat/sub/KsubM/sub of 6.9?×?10sup6/sup?Msup?1/sup ssup?1/sup. The EcoCAγ inhibition profile with a broad series of known CA inhibitors, the substituted benzene-sulphonamides, and clinically licenced drugs was explored. Benzolamide showed a KsubI/sub lower than 100?nM. Our study reinforces the hypothesis that the synthesis of new drugs capable of interfering selectively with the bacterial CA activity, avoiding the inhibition of the human α -CAs, is achievable and may lead to novel antibacterials.