title: Identification and characterization of Di- and tripeptide transporter DtpT of Listeria monocytogenes EGD-e.
abstract: Listeria monocytogenes is a gram-positive intracellular pathogen responsible for opportunistic infections in humans and animals. Here we identified and characterized the dtpT gene (lmo0555) of L. monocytogenes EGD-e, encoding the di- and tripeptide transporter, and assessed its role in growth under various environmental conditions as well as in the virulence of L. monocytogenes. Uptake of the dipeptide Pro-[14C]Ala was mediated by the DtpT transporter and was abrogated in a DeltadtpT isogenic deletion mutant. The DtpT transporter was shown to be required for growth when the essential amino acids leucine and valine were supplied as peptides. The protective effect of glycine- and proline-containing peptides during growth in defined medium containing 3% NaCl was noted only in L. monocytogenes EGD-e, not in the DeltadtpT mutant strain, indicating that the DtpT transporter is involved in salt stress protection. Infection studies showed that DtpT contributes to pathogenesis in a mouse infection model but has no role in bacterial growth following infection of J774 macrophages. These studies reveal that DptT may contribute to the virulence of L. monocytogenes.
authors.affiliation: Wageningen Centre for Food Sciences (WCFS) and Laboratory of Food Microbiology, Wageningen University, Bomenweg 2, 6703 HD Wageningen, The Netherlands.
authors.forename: Jeroen A
authors.initials: JA
authors.lastname: Wouters
authors.forename: Torsten
authors.initials: T
authors.lastname: Hain
authors.forename: Ajub
authors.initials: A
authors.lastname: Darji
authors.forename: Eric
authors.initials: E
authors.lastname: Hüfner
authors.forename: Henrike
authors.initials: H
authors.lastname: Wemekamp-Kamphuis
authors.forename: Trinad
authors.initials: T
authors.lastname: Chakraborty
authors.forename: Tjakko
authors.initials: T
authors.lastname: Abee
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D003470:Culture Media; D004151:Dipeptides / Q000378:metabolism*; D005260:Female; D017353:Gene Deletion; D018869:Heat-Shock Response; D006801:Humans; D008089:Listeria monocytogenes / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity*; D008088:Listeriosis / Q000382:microbiology; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009842:Oligopeptides / Q000378:metabolism*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D004151:Dipeptides; D026901:Membrane Transport Proteins; D009842:Oligopeptides