Specificity of the second binding protein of the peptide ABC-transporter (Dpp) of Lactococcus lactis IL1403.
The genome sequence of Lactococcus lactis IL1403 revealed the presence of a putative peptide-binding protein-dependent ABC-transporter (Dpp). The genes for two peptide-binding proteins (dppA and dppP) precede the membrane components, which include two transmembrane protein genes (dppB and dppC) and two ATP-binding protein genes (dppD and dppF). In this work, the gene specifying the second peptide-binding protein (DppP) was cloned under the control of the nisin promoter. The protein fused to a carboxyl-terminal histidine tag (DppP-His(6)) was purified and its binding properties were determined by monitoring the intrinsic fluorescence changes observed upon ligand binding. The major features of peptide binding to DppP-His(6) include: (i) a requirement for a free N-terminal alpha-amino group in the ligand; (ii) a high affinity for di-, tri- and tetra-peptides; (iii) affinity constants for peptide binding independent of pH; and (iv) a high affinity for D-isomer-containing peptides. Remarkably, the features (ii), (iii) and (iv) differ from those previously reported for DppA-His(6), suggesting that DppP-His(6) is a more versatile peptide-binding protein that could have additional functions.
Instituto de Agroqui;mica y Tecnologi;a de Alimentos (C.S.I.C.), Apartado 73, 46100, Valencia, Burjasot, Spain. yolsanz@iata.csic.es
Yolanda
Y
Sanz
Fidel
F
Toldrá
Pierre
P
Renault
Bert
B
Poolman
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004151:Dipeptides / Q000378:metabolism*; D013294:Lactococcus lactis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008074:Lipoproteins; D011485:Protein Binding; D021381:Protein Transport
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004151:Dipeptides; D008074:Lipoproteins; C046506:oligopeptide-binding protein, bacteria