title: The β-carbonic anhydrases from Mycobacterium tuberculosis as drug targets.
abstract: Three β-carbonic anhydrases (CAs, EC 4.2.1.1), encoded by the gene Rv1284 (mtCA 1) Rv3588c (mtCA 2) and Rv3273 (mtCA 3) are present in the human pathogen Mycobacterium tuberculosis. These enzymes were cloned and they showed appreciable catalytic activity for CO(2) hydration, with k(cat) of 3.9 x 10(5) s(-1), and k(cat)/K(m) of 3.7 x 10(7) M(-1).s1 for mtCA 1, of 9.8 x 10(5) s(-1), and k(cat)/K(m) of 9.3 x 10(7) M(-1).s(-1) for mtCA 2 and k(cat) of 4.3 x 10(5) s(-1), and a k(cat)/K(m) of 4.0 x 10(7) M(-1).s(-1) for mtCA 3, respectively. The Rv3273 gene product is predicted to be a 764 amino acid residues polypeptide, consisting of a sulfate transporter domain (amino acids 121-414) in addition to the β-CA mentioned above (which is encoded by residues 571-741). All these enzymes were inhibited appreciably by many sulfonamides and sulfamates, in the nanomolar - micromolar range, whereas some subnanomolar inhibitors were also reported for two of them (mtCA 1 and mtCA 3). As sulfonamides also efficiently inhibit dehydropteroate synthetase (DHPS), the contribution of mtCAs and DHPS inhibition to a possible antimycobacterial action of these drugs must be better understood. It has been, however, proven that mtCAs are druggable targets, with a real potential for developing antimycobacterial agents with a diverse mechanism of action compared to the clinically used drugs for which many strains exhibit multi-drug resistance and extensive multi-drug resistance, although for the moment no in vivo inhibition of the bacteria could be evidenced with the presently available drugs due to lack of penetrability through the mycolic acid cell wall of M. tuberculosis.
authors.affiliation: Department of Gastroenterology, Kochi Medical School, Nankoku, Kochi, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Nishimori
authors.forename: Tomoko
authors.initials: T
authors.lastname: Minakuchi
authors.forename: Alfonso
authors.initials: A
authors.lastname: Maresca
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Carta
authors.forename: Andrea
authors.initials: A
authors.lastname: Scozzafava
authors.forename: Claudiu T
authors.initials: CT
authors.lastname: Supuran
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002257:Carbonic Anhydrase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D002256:Carbonic Anhydrases / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D007527:Isoenzymes / Q000187:drug effects* / Q000378:metabolism; D008969:Molecular Sequence Data; D058990:Molecular Targeted Therapy; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D013329:Structure-Activity Relationship; D013449:Sulfonamides / Q000494:pharmacology; D013451:Sulfonic Acids / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002257:Carbonic Anhydrase Inhibitors; D007527:Isoenzymes; D013449:Sulfonamides; D013451:Sulfonic Acids; C005741:sulfamic acid; D002256:Carbonic Anhydrases