Sanz Yolanda, Toldrá Fidel, Renault Pierre, Poolman Bert
Instituto de Agroqui;mica y Tecnologi;a de Alimentos (C.S.I.C.), Apartado 73, 46100, Valencia, Burjasot, Spain.
FEMS Microbiol Lett. 2003 Oct 10;227(1):33-8. doi: 10.1016/S0378-1097(03)00662-1.
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.
乳酸乳球菌IL1403的基因组序列显示存在一种假定的依赖肽结合蛋白的ABC转运蛋白（Dpp）。两个肽结合蛋白（dppA和dppP）的基因位于膜成分之前，膜成分包括两个跨膜蛋白基因（dppB和dppC）和两个ATP结合蛋白基因（dppD和dppF）。在这项研究中，编码第二个肽结合蛋白（DppP）的基因在乳链菌肽启动子的控制下被克隆。与羧基末端组氨酸标签融合的蛋白（DppP-His(6)）被纯化，并通过监测配体结合时观察到的内在荧光变化来确定其结合特性。肽与DppP-His(6)结合的主要特征包括：（i）配体中需要一个游离的N末端α-氨基；（ii）对二肽、三肽和四肽具有高亲和力；（iii）肽结合的亲和常数与pH无关；（iv）对含D-异构体的肽具有高亲和力。值得注意的是，特征（ii）、（iii）和（iv）与先前报道的DppA-His(6)不同，这表明DppP-His(6)是一种更具通用性的肽结合蛋白，可能具有额外的功能。
