Receptor-binding domain of human alpha 2-macroglobulin. Expression, folding and biochemical characterization of a high-affinity recombinant derivative.
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.
Holtet
T L
TL
Department of Chemistry, University of Arhus, Denmark.
Nielsen
K L
KL
Etzerodt
M
M
Moestrup
S K
SK
Gliemann
J
J
Sottrup-Jensen
L
L
Thøgersen
H C
HC
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D015870:Gene Expression; D018014:Gene Transfer Techniques; D006801:Humans; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010920:Placenta / Q000737:chemistry; D010957:Plasmids; D017510:Protein Folding; D011971:Receptors, Immunologic / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D000511:alpha-Macroglobulins / Q000737:chemistry* / Q000378:metabolism
D000596:Amino Acids; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D010446:Peptide Fragments; D011971:Receptors, Immunologic; D011994:Recombinant Proteins; D000511:alpha-Macroglobulins