Premium
On the binding mechanism of the peptide receptor of the oligopeptide transport system of Lactococcus lactis
Author(s) -
Lanfermeijer Frank C.,
Detmers Frank J.M.,
Konings Wil N.,
Poolman Bert
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.14.3649
Subject(s) - lactococcus lactis , oligopeptide , peptide , biochemistry , biology , amino acid , residue (chemistry) , cysteine , binding site , lysine , stereochemistry , chemistry , bacteria , enzyme , lactic acid , genetics
Lactococcus lactis degrades exogenous proteins such as β‐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.