EXPRESSION AND REFOLDING OF A HIGH-AFFINITY RECEPTOR-BINDING DOMAIN FROM RAT ALPHA(1)-MACROGLOBULIN

A recombinant version of the receptor binding domain of rat alpha(1)-m acroglobulin (RBDv) consisting of residues 1319-1474 has been expresse d in E. roll. Competition experiments with I-125-labelled methylamine treated human alpha(2)-macroglobulin reveal that the alpha(1)-macroglo bulio-RBDv exhibit the same high affinity for the alpha 2-macroglobuli n receptor as the entire 40 MDa light chain from rat alpha(1)-macroglo bulin. It is therefore concluded, that all determinants for receptor i nteraction reside in the C-terminal approx. 150 residues of the alpha- macroglobulin subunit.