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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Amino Acids / analysis
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Base Sequence
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Binding Sites
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Binding, Competitive
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Electrophoresis, Polyacrylamide Gel
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Escherichia coli / genetics
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Female
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Gene Expression
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Gene Transfer Techniques
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Humans
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Low Density Lipoprotein Receptor-Related Protein-1
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Molecular Sequence Data
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Peptide Fragments / chemistry
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Peptide Fragments / genetics
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Peptide Fragments / metabolism
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Placenta / chemistry
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Plasmids
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Protein Folding
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Receptors, Immunologic / metabolism*
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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alpha-Macroglobulins / chemistry*
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alpha-Macroglobulins / metabolism
Substances
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Amino Acids
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Low Density Lipoprotein Receptor-Related Protein-1
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Peptide Fragments
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Receptors, Immunologic
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Recombinant Proteins
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alpha-Macroglobulins