title: Characterization of the C-terminal domain of Helicobacter pylori vacuolating toxin and its relationship with extracellular toxin production.
abstract: Helicobacter pylori vacuolating cytotoxin (VacA) induces gastric epithelial necrosis. Its C-terminal domain is hypothesized to be responsible for extracellular translocation of the mature cytotoxin. In this study, genetic-structural properties of VacA C-terminal domain and the level of cytotoxin secretion were investigated. Sau3AI-HaeIII restriction fragment length polymorphism (RFLP) analysis of the 1.1-kb PCR-amplified vacA fragment revealed 14 distinct combined patterns among 87 clinical isolates. Of the 4 popular groups (A-a, A-b, A-f, and B-a), A-a strains produced a higher level of the VacA protein than A-b strains and than A-f strains (P < 0.05). Sequence analysis and secondary structure prediction supported a beta-barrel structure that might act as a selective export channel like Iga beta-core of IgA proteases. Sequence differences in the predicted beta-barrel were present among strains of different RFLPs.
authors.affiliation: Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: H J
authors.initials: HJ
authors.lastname: Wang
authors.forename: P C
authors.initials: PC
authors.lastname: Chang
authors.forename: C H
authors.initials: CH
authors.lastname: Kuo
authors.forename: C S
authors.initials: CS
authors.lastname: Tzeng
authors.forename: W C
authors.initials: WC
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001427:Bacterial Toxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016480:Helicobacter pylori / Q000378:metabolism*; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017421:Sequence Analysis
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; C074689:VacA protein, Helicobacter pylori