Bottomley S P, Beckingham J A, Murphy J P, Atkinson M, Atkinson T, Hinton R J, Gore M G
Department of Biochemistry, University of Southampton, Bassett Crescent East, UK.
Bioseparation. 1995;5(6):359-67.
Protein L is a multi-domain, cell wall constituent of certain strains of Peptostreptococcus magnus, which binds to the variable domain of the L-chains of Ig. A gene fragment which codes for a single Ig-binding domain of protein L (Ppl-1) was cloned into a modified pKK223-3 vector and over-expressed in E. coli JM103. A rapid protein purification protocol is described. In these studies, purified Ppl-1 was immobilised on to an agarose gel and tested against an array of Igs and Ig fragments. It was found that Ppl-1-bound Igs from a number of different sources via interactions with the L kappa-chain. An enzyme linked immunosorbant assay has been developed to assay the binding of Ppl-1 to IgG. The incubation of Ppl-1 with human serum does not produce an immunoprecipitate, thus suggesting one unique interaction per binding domain which has been confirmed by ELISA. These experiments demonstrate the potential value of Ppl-1 as an immunological tool and as an affinity chromatography ligand for the purification of Igs.
蛋白L是某些大消化链球菌菌株的一种多结构域细胞壁成分，它能与Ig的L链可变结构域结合。编码蛋白L单一Ig结合结构域（Ppl-1）的基因片段被克隆到一个修饰的pKK223-3载体中，并在大肠杆菌JM103中过量表达。本文描述了一种快速蛋白质纯化方案。在这些研究中，将纯化的Ppl-1固定在琼脂糖凝胶上，并针对一系列Ig和Ig片段进行测试。发现Ppl-1通过与Lκ链的相互作用结合来自多种不同来源的Ig。已开发出一种酶联免疫吸附测定法来检测Ppl-1与IgG的结合。Ppl-1与人血清孵育不会产生免疫沉淀，因此表明每个结合结构域存在一种独特的相互作用，这已通过ELISA得到证实。这些实验证明了Ppl-1作为一种免疫学工具以及作为用于纯化Ig的亲和色谱配体的潜在价值。
