人α2-巨球蛋白的受体结合结构域。一种高亲和力重组衍生物的表达、折叠及生化特性分析

Receptor-binding domain of human alpha 2-macroglobulin. Expression, folding and biochemical characterization of a high-affinity recombinant derivative.

作者信息

Holtet T L, Nielsen K L, Etzerodt M, Moestrup S K, Gliemann J, Sottrup-Jensen L, Thøgersen H C

机构信息

Department of Chemistry, University of Arhus, Denmark.

出版信息

FEBS Lett. 1994 May 16;344(2-3):242-6. doi: 10.1016/0014-5793(94)00349-1.

DOI:10.1016/0014-5793(94)00349-1

PMID:7514545

Abstract

A recombinant version of the receptor binding domain (RBDv) of human alpha 2-macroglobulin (alpha 2M) has been expressed in E. coli and refolded using a novel iterative procedure. RBDv (Val1299-Ala1451) is extended by 15 residues at the N-terminal side of the Lys1313-Glu papain cleavage site in human alpha 2M. RBDv contains the intra-chain bridge Cys1329-Cys1444 and is soluble and monomeric. Competition experiments with 125I-labelled methylamine-treated alpha 2M reveal that RBDv binds to the placental receptor for transformed alpha 2M with a Kd of 8 nM, i.e. the binding affinity of RBDv is of the same order of magnitude as the intrinsic affinity for binding of one domain in transformed alpha 2M to one receptor molecule.

摘要

人α2-巨球蛋白（α2M）受体结合域的重组版本（RBDv）已在大肠杆菌中表达，并使用一种新颖的迭代程序进行重折叠。RBDv（Val1299-Ala1451）在人α2M中Lys1313-Glu木瓜蛋白酶切割位点的N端一侧延伸了15个残基。RBDv包含链内桥Cys1329-Cys1444，并且是可溶的单体。用125I标记的甲胺处理的α2M进行的竞争实验表明，RBDv以8 nM的Kd值与转化型α2M的胎盘受体结合，即RBDv的结合亲和力与转化型α2M中一个结构域与一个受体分子结合的固有亲和力处于同一数量级。