title: Di-tripeptides and oligopeptides are taken up via distinct transport mechanisms in Lactococcus lactis.
abstract: Lactococcus lactis ML3 possesses two different peptide transport systems of which the substrate size restriction and specificity have been determined. The first system is the earlier-described proton motive force-dependent di-tripeptide carrier (E. J. Smid, A. J. M. Driessen, and W. N. Konings, J. Bacteriol. 171:292-298, 1989). The second system is a metabolic energy-dependent oligopeptide transport system which transports peptides of four to at least six amino acid residues. The involvement of a specific oligopeptide transport system in the utilization of tetra-alanine and penta-alanine was established in a mutant of L. lactis MG1363 that was selected on the basis of resistance to toxic analogs of alanine and alanine-containing di- and tripeptides. This mutant is unable to transport alanine, dialanine, and trialanine but still shows uptake of tetra-alanine and penta-alanine. The oligopeptide transport system has a lower activity than the di-tripeptide transport system. Uptake of oligopeptides occurs in the absence of a proton motive force and is specifically inhibited by vanadate. The oligopeptide transport system is most likely driven by ATP or a related energy-rich, phosphorylated intermediate.
authors.affiliation: Department of Microbiology, University of Groningen, Haren, The Netherlands.
authors.forename: E R
authors.initials: ER
authors.lastname: Kunji
authors.forename: E J
authors.initials: EJ
authors.lastname: Smid
authors.forename: R
authors.initials: R
authors.lastname: Plapp
authors.forename: B
authors.initials: B
authors.lastname: Poolman
authors.forename: W N
authors.initials: WN
authors.lastname: Konings
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis; D000595:Amino Acid Sequence; D001149:Arsenates / Q000494:pharmacology; D001693:Biological Transport, Active; D004151:Dipeptides / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D004734:Energy Metabolism; D005947:Glucose / Q000378:metabolism; D013294:Lactococcus lactis / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016296:Mutagenesis; D009842:Oligopeptides / Q000378:metabolism*; D013379:Substrate Specificity; D014638:Vanadates / Q000494:pharmacology; D015091:beta-Alanine / Q000031:analogs & derivatives / Q000633:toxicity
chemical_list: D001149:Arsenates; D004151:Dipeptides; D009842:Oligopeptides; D015091:beta-Alanine; C006977:3-chloroalanine; D014638:Vanadates; D000255:Adenosine Triphosphate; D005947:Glucose; C025657:arsenic acid