title: A proteomic approach for the identification of bismuth-binding proteins in Helicobacter pylori.
abstract: Helicobacter pylori is a major human pathogen that can cause peptic ulcers and chronic gastritis. Bismuth-based triple or quadruple therapies are commonly recommended for the treatment of H. pylori infections. However, the molecular mechanisms underlying treatment with bismuth are currently not fully understood. We have conducted a detailed comparative proteomic analysis of H. pylori cells both before and after treatment with colloidal bismuth subcitrate (CBS). Eight proteins were found to be significantly upregulated or downregulated in the presence of CBS (20 microg mL(-1)). Bismuth-induced oxidative stress was confirmed by detecting higher levels of lipid hydroperoxide (approximately 1.8 times) and hemin (approximately 3.4 times), in whole cell extracts of bismuth-treated H. pylori cells, compared with those from untreated cells. The presence of bismuth also led to an approximately eightfold decrease in cellular protease activities. Using immobilized-bismuth affinity chromatography, we isolated and subsequently identified seven bismuth-binding proteins from H. pylori cell extracts. The intracellular levels of four of these proteins (HspA, HspB, NapA and TsaA) were influenced by the addition of CBS, which strongly suggests that they interact directly with bismuth. The other bismuth-interacting proteins identified were two enzymes (fumarase and the urease subunit UreB), and a translational factor (Ef-Tu). Our data suggest that the inhibition of proteases, modulation of cellular oxidative stress and interference with nickel homeostasis may be key processes underlying the molecular mechanism of bismuth's actions against H. pylori.
authors.affiliation: Department of Chemistry and Open Laboratory of Chemical Biology, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China.
authors.forename: Ruiguang
authors.initials: R
authors.lastname: Ge
authors.forename: Xuesong
authors.initials: X
authors.lastname: Sun
authors.forename: Qing
authors.initials: Q
authors.lastname: Gu
authors.forename: Rory M
authors.initials: RM
authors.lastname: Watt
authors.forename: Julian A
authors.initials: JA
authors.lastname: Tanner
authors.forename: Benjamin Chun Yu
authors.initials: BC
authors.lastname: Wong
authors.forename: Harry Huaxiang
authors.initials: HH
authors.lastname: Xia
authors.forename: Jian-Dong
authors.initials: JD
authors.lastname: Huang
authors.forename: Qing-Yu
authors.initials: QY
authors.lastname: He
authors.forename: Hongzhe
authors.initials: H
authors.lastname: Sun
mesh_terms: D001426:Bacterial Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D020869:Gene Expression Profiling / Q000379:methods; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D016480:Helicobacter pylori / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008667:Metalloproteins / Q000032:analysis* / Q000235:genetics; D008826:Microbial Sensitivity Tests; D009532:Nickel / Q000378:metabolism; D009942:Organometallic Compounds / Q000494:pharmacology; D011480:Protease Inhibitors; D040901:Proteomics / Q000379:methods*
chemical_list: D001426:Bacterial Proteins; D008667:Metalloproteins; D009942:Organometallic Compounds; D011480:Protease Inhibitors; C028053:bismuth-binding proteins; D009532:Nickel; C002791:bismuth tripotassium dicitrate