title: Roles of the Peptide Transport Systems and Aminopeptidase PepA in Peptide Assimilation by Helicobacter pylori.
abstract: Peptide assimilation in Helicobacter pylori necessitates a coordinated working of the peptide transport systems (PepTs) and aminopeptidase (PepA). We found that H. pylori hydrolyzes two detector peptides, L-phenylalanyl-L-3-thiaphenylalanine (PSP) and L-phenylalanyl-L-2- sulfanilylglycine (PSG), primarily before intake and excludes their antibacterial effects, whereas Escherichia coli readily transports them with resultant growth inhibition. PSP assimilation by H. pylori was inhibited by aminopeptidase inhibitor bestatin, but not by dialanine or cyanide-m-chlorophenylhydrazone, contrary to that of E. coli. RT- and qRT-PCR analyses showed that H. pylori may express first the PepTs (e.g., DppA and DppB) and then PepA. In addition, western blot analysis of PepA suggested that the bacterium secretes PepA in response to specific inducers.
authors.affiliation: Department of Bioinformatics & Graduate School of Biotechnology, Korea University, Sejong 339-700, Republic of Korea.
authors.forename: Mi Ran
authors.initials: MR
authors.lastname: Ki
authors.affiliation: Department of Bioinformatics & Graduate School of Biotechnology, Korea University, Sejong 339-700, Republic of Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Bioinformatics & Graduate School of Biotechnology, Korea University, Sejong 339-700, Republic of Korea.
authors.forename: Soon Kyu
authors.initials: SK
authors.lastname: Yun
authors.affiliation: Department of Bioinformatics & Graduate School of Biotechnology, Korea University, Sejong 339-700, Republic of Korea.
authors.forename: Kyung Min
authors.initials: KM
authors.lastname: Choi
authors.affiliation: Department of Bioinformatics & Graduate School of Biotechnology, Korea University, Sejong 339-700, Republic of Korea.
authors.forename: Se Young
authors.initials: SY
authors.lastname: Hwang
mesh_terms: D000626:Aminopeptidases / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D004151:Dipeptides / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D020869:Gene Expression Profiling; D016480:Helicobacter pylori / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis; D026901:Membrane Transport Proteins; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D000900:Anti-Bacterial Agents; D004151:Dipeptides; C523052:L-phenylalanyl-L-2-sulfanilylglycine; D026901:Membrane Transport Proteins; C049315:phenylalanyl-3-thiaphenylalanine; C043912:peptide permease; D000626:Aminopeptidases
keywords: Helicobacter pylori; PepA; PepTs; detector peptides; peptide transport