A new β-carbonic anhydrase from Brucella suis, its cloning, characterization, and inhibition with sulfonamides and sulfamates, leading to impaired pathogen growth

A β-carbonic anhydrase (CA, EC 4.2.1.1) from the bacterial pathogen Brucella suis, bsCA II, has been cloned, purified, and characterized kinetically. bsCA II showed high catalytic activity for the hydration of CO2 to bicarbonate, with a kcat of 1.1 × 106, and kcat/Km of 8.9 × 107 M−1 s−1. A panel of sulfonamides and sulfamates have been investigated for inhibition of this enzyme. All types of activities, from the low nanomolar to the micromolar, have been detected for these derivatives, which showed inhibition constants in the range of 7.3 nM–8.56 μM. The best bsCA II inhibitors were some glycosylated sulfanilamides, aliphatic sulfamates, and halogenated sulfanilamides, with inhibition constants of 7.3–87 nM. Some of these dual inhibitors of bsCA I and II, also inhibited bacterial growth in vitro, in liquid cultures. These promising data on live bacteria allow us to propose bacterial β-CA inhibition as an approach for obtaining anti-infective agents with a new mechanism of action compared to classical antibiotics.

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