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Receptor‐binding domain of human α 2 ‐macroglobulin Expression, folding and biochemical characterization of a high‐affinity recombinant derivative
Author(s) -
Holtet Thor Las,
Nielsen Kåre Lehmann,
Etzerodt Michael,
Moestrup Søren Kragh,
Gliemann Jørgen,
Sottrup-Jensen Lars,
Thøgersen Hans Christian
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)00349-1
Subject(s) - chemistry , recombinant dna , papain , cleavage (geology) , biochemistry , receptor , macroglobulin , stereochemistry , biology , enzyme , paleontology , fracture (geology) , gene
A recombinant version of the receptor binding domain (RBDv) of human α 2 ‐macroglobulin (α 2 M) has been expressed in E. coli and refolded using a novel iterative procedure. RBDv (Val 1299 ‐Ala 1451 ) is extended by 15 residues at the N‐terminal side of the Lys 1313 ‐Glu papain cleavage site in human α 2 M. RBDv contains the intra‐chain bridge Cys 1329 ‐Cys 1444 and is soluble and monomeric. Competition experiments with 125 I‐labelled methylamine‐treated α 2 M reveal that RBDv binds to the placental receptor for transformed α 2 M with a K d 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 α 2 M to one receptor molecule.