title: On the binding mechanism of the peptide receptor of the oligopeptide transport system of Lactococcus lactis.
abstract: Lactococcus lactis degrades exogenous proteins such as beta-casein to peptides of 4-30 amino acids, and uses these as nitrogen sources. The binding protein or receptor (OppA(Ll)) of the oligopeptide transport system (Opp) of L.LACTIS: has the unique capacity to bind peptides from five up to at least 20 residues. To study the binding mechanism of OppA(Ll), nonameric peptides were used in which the cysteine at position 1, 3, 4, 5, 6, 7 or 9 was selectively labeled with either bulky and non-fluorescent or bulky and fluorescent groups. Also, nonameric peptides with a non-natural residue, azatryptophan, at positions 3 or 7 were used. The fluorescence of azatryptophan reports on the polarity of the environment. The studies indicate that the binding protein encloses the first six amino acids of the peptide, whereas the remaining residues stick out and interact with the surface of the binding protein. The peptide binding mechanism of OppA(Ll) is discussed in relation to known three-dimensional structures of members of this class of proteins, and an adaptation of the general binding mechanism is proposed.
authors.affiliation: Departments of Microbiology and Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, The Netherlands.
authors.forename: F C
authors.initials: FC
authors.lastname: Lanfermeijer
authors.forename: F J
authors.initials: FJ
authors.lastname: Detmers
authors.forename: W N
authors.initials: WN
authors.lastname: Konings
authors.forename: B
authors.initials: B
authors.lastname: Poolman
mesh_terms: D002731:4-Chloromercuribenzenesulfonate / Q000378:metabolism / Q000494:pharmacology; D000595:Amino Acid Sequence; D001372:Aza Compounds / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins; D001665:Binding Sites; D001692:Biological Transport; D003545:Cysteine / Q000378:metabolism; D005456:Fluorescent Dyes; D013294:Lactococcus lactis / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D015394:Molecular Structure; D009282:Naphthalenesulfonates / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism
chemical_list: D001372:Aza Compounds; D001426:Bacterial Proteins; D005456:Fluorescent Dyes; D026901:Membrane Transport Proteins; D009282:Naphthalenesulfonates; D009842:Oligopeptides; D011956:Receptors, Cell Surface; C058843:8-azatryptophan; C069278:2-(4'-acetamidoanilino)naphthalene-6-sulfonic acid; C037230:oligopeptide permease, Bacteria; D002731:4-Chloromercuribenzenesulfonate; D014364:Tryptophan; D003545:Cysteine