Cloning, polymorphism, and inhibition of beta-carbonic anhydrase of Helicobacter pylori.
BACKGROUND
Carbonic anhydrase (CA) catalyzes the reversible hydration of CO(2) to bicarbonate and a proton, and alpha-class CA has been reported to facilitate the acid acclimation of Helicobacter pylori (hpalphaCA). The purpose of this study was to characterize the beta-class CA of H. pylori (hpbetaCA) and elucidate the role of this enzyme as a possible drug target for eradication therapy.


METHODS
We isolated DNA clones of independent H. pylori strains obtained from patients with gastritis (n = 15), gastric ulcer (n = 6), or gastric cancer (n = 16), and then studied genetic polymorphisms. In addition, the susceptibility of H. pylori to sulpiride, an antiulcer drug and efficient inhibitor of both hpalphaCA and hpbetaCA, was studied with an in vitro killing assay.


RESULTS
DNA sequences of all 37 hpbetaCA clones encoded a 221 amino acid polypeptide with a variety of polymorphisms (57 types of amino acid substitution at 48 residue positions). There was no polymorphism functionally relevant to the gastric lesion type. One strain included unique residues that were not seen in the other 36 clones from Japanese patients but which were found in a strain obtained from the United Kingdom. Sulpiride had killing effects at concentrations greater than 200 microg/ml for H. pylori, including strains resistant to clarithromycin, metronidazole, or ampicillin.


CONCLUSIONS
Helicobacter pylori might have evolved independently in the Caucasian and Japanese populations. Dual inhibition of alpha-and beta-class CAs could be applied as alternative therapy for eradication of H. pylori.
Morishita
Saori
S
Department of Gastroenterology and Hepatology, Kochi Medical School, Nankoku 783-8505, Japan.
Nishimori
Isao
I
Minakuchi
Tomoko
T
Onishi
Saburo
S
Takeuchi
Hiroaki
H
Sugiura
Tetsuro
T
Vullo
Daniela
D
Scozzafava
Andrea
A
Supuran
Claudiu T
CT
D024402:Carbonic Anhydrase II / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics*; D016480:Helicobacter pylori / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D013469:Sulpiride / Q000494:pharmacology
D002257:Carbonic Anhydrase Inhibitors; D004269:DNA, Bacterial; D013469:Sulpiride; D024402:Carbonic Anhydrase II