Diversity of oligopeptide transport specificity in Lactococcus lactis species. A tool to unravel the role of OppA in uptake specificity.
The specific oligopeptide transport system Opp is essential for growth of Lactococcus lactis in milk. We examined the biodiversity of oligopeptide transport specificity in the L. lactis species. Six strains were tested for (i) consumption of peptides during growth in a chemically defined medium and (ii) their ability to transport these peptides. Each strain demonstrated some specific preferences for peptide utilization, which matched the specificity of peptide transport. Sequencing of the binding protein OppA in some strains revealed minor differences at the amino acid level. The differences in specificity were used as a tool to unravel the role of the binding protein in transport specificity. The genes encoding OppA in four strains were cloned and expressed in L. lactis MG1363 deleted for its oppA gene. The substrate specificity of these engineered strains was found to be similar to that of the L. lactis MG1363 parental strain, whichever oppA gene was expressed. In situ binding experiments demonstrated the ability of OppA to interact with non-transported peptides. Taken together, these results provide evidence for a new concept. Despite that fact that OppA is essential for peptide transport, it is not the (main) determinant of peptide transport specificity in L. lactis.
Charbonnel
Pascale
P
Useful Bacterial Surface Proteins, Unité de Recherches Laitières et Génétique Appliquée, Institut National de la Recherche Agronomique, 78352 Jouy-en-Josas Cedex, France.
Lamarque
Mauld
M
Piard
Jean-Christophe
JC
Gilbert
Christophe
C
Juillard
Vincent
V
Atlan
Danièle
D
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000502:physiology; D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology; D013294:Lactococcus lactis / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D008074:Lipoproteins / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism*; D015202:Protein Engineering; D021381:Protein Transport / Q000235:genetics; D016415:Sequence Alignment; D013379:Substrate Specificity
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D008074:Lipoproteins; D009842:Oligopeptides; C046506:oligopeptide-binding protein, bacteria