title: Importance of the C-terminal histidine residues of Helicobacter pylori GroES for Toll-like receptor 4 binding and interleukin-8 cytokine production.
abstract: Helicobacter pylori infection is associated with the development of gastric and duodenal ulcers as well as gastric cancer. GroES of H. pylori (HpGroES) was previously identified as a gastric cancer-associated virulence factor. Our group showed that HpGroES induces interleukin-8 (IL-8) cytokine release via a Toll-like receptor 4 (TLR4)-dependent mechanism and domain B of the protein is crucial for interactions with TLR4. In the present study, we investigated the importance of the histidine residues in domain B. To this end, a series of point mutants were expressed in Escherichia coli, and the corresponding proteins purified. Interestingly, H96, H104 and H115 were not essential, whereas H100, H102, H108, H113 and H118 were crucial for IL-8 production and TLR4 interactions in KATO-III cells. These residues were involved in nickel binding. Four of five residues, H102, H108, H113 and H118 induced certain conformation changes in extended domain B structure, which is essential for interactions with TLR4 and consequent IL-8 production. We conclude that interactions of nickel ions with histidine residues in domain B help to maintain the conformation of the C-terminal region to conserve the integrity of the HpGroES structure and modulate IL-8 release.
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
authors.forename: Haur
authors.initials: H
authors.lastname: Lee
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Su
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
authors.forename: Bo-Shih
authors.initials: BS
authors.lastname: Huang
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
authors.forename: Feng-Tse
authors.initials: FT
authors.lastname: Hsieh
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
authors.forename: Ya-Hui
authors.initials: YH
authors.lastname: Chang
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
authors.forename: Shiou-Ru
authors.initials: SR
authors.lastname: Tzeng
authors.affiliation: Department of Agricultural Chemistry, National Taiwan University, Taipei, 106, Taiwan.
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Hsu
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.|Graduate Institute of Oral Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
authors.forename: Po-Tsang
authors.initials: PT
authors.lastname: Huang
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.|Graduate Institute of Oral Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
authors.forename: Kuo-Long
authors.initials: KL
authors.lastname: Lou
authors.affiliation: Department of Biochemistry, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Yeng-Tseng
authors.initials: YT
authors.lastname: Wang
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
authors.forename: Lu-Ping
authors.initials: LP
authors.lastname: Chow
mesh_terms: D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D018835:Chaperonin 10 / Q000737:chemistry* / Q000378:metabolism; D017124:Conserved Sequence; D016480:Helicobacter pylori / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D051197:Toll-Like Receptor 4 / Q000737:chemistry* / Q000378:metabolism
chemical_list: C508606:CXCL8 protein, human; D018835:Chaperonin 10; D016209:Interleukin-8; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4