Specificity of peptide transport systems in Lactococcus lactis: evidence for a third system which transports hydrophobic di- and tripeptides.

TitleSpecificity of peptide transport systems in Lactococcus lactis: evidence for a third system which transports hydrophobic di- and tripeptides.
Publication TypeJournal Article
Year of Publication1995
AuthorsFoucaud, C, Kunji, ERS, Hagting, A, Richard, J, Konings, WN, Desmazeaud, M, Poolman, B
JournalJ Bacteriol
Volume177
Issue16
Pagination4652-7
Date Published1995 Aug
ISSN0021-9193
KeywordsAmino Acid Sequence, Biological Transport, Carrier Proteins, Dipeptides, Drug Resistance, Microbial, Gene Expression, Hydrogen-Ion Concentration, Lactococcus lactis, Molecular Sequence Data, Mutation, Oligopeptides, Substrate Specificity
Abstract

A proton motive force-driven di-tripeptide carrier protein (DtpT) and an ATP-dependent oligopeptide transport system (Opp) have been described for Lactococcus lactis MG1363. Using genetically well-defined mutants in which dtpT and/or opp were inactivated, we have now established the presence of a third peptide transport system (DtpP) in L. lactis. The specificity of DtpP partially overlaps that of DtpT. DtpP transports preferentially di- and tripeptides that are composed of hydrophobic (branched-chain amino acid) residues, whereas DtpT has a higher specificity for more-hydrophilic and charged peptides. The toxic dipeptide L-phenylalanyl-beta-chloro-L-alanine has been used to select for a di-tripeptide transport-negative mutant with the delta dtpT strain as a genetic background. This mutant is unable to transport di- and tripeptides but still shows uptake of amino acids and oligopeptides. The DtpP system is induced in the presence of di- and tripeptides containing branched-chain amino acids. The use of ionophores and metabolic inhibitors suggests that, similar to Opp, DtpP-mediated peptide transport is driven by ATP or a related energy-rich phosphorylated intermediate.

Alternate JournalJ. Bacteriol.
Citation Key1145
PubMed ID7642491
PubMed Central IDPMC177229