title: Expression and purification of biologically active domain I of the human polymeric immunoglobulin receptor.
abstract: Previous studies using proteolytic fragments and synthetic peptides have indicated that domain I of human polymeric immunoglobulin receptor (PIgR) is necessary for ligand binding. The expression in E. coli, and subsequent IgM-affinity purification of domain I of human PIgR is described. The recombinant domain I protein (rDI) was similar in structure to native SC domain I in that it bound specifically to MAb 6G11, an antibody which recognizes a critical portion of the PIg binding site in domain I. The biological activity of rDI was indicated by high affinity binding to PIgA (Kd = 1.6 x 10(-7) M) and IgM (Kd = 5.1 x 10(-7) M). Domain I of human SC is therefore sufficient for binding to PIg.
authors.affiliation: Department of Pediatrics, University of Texas Medical Branch, Galveston 77555-0366.
authors.forename: M A
authors.initials: MA
authors.lastname: Bakos
authors.forename: S G
authors.initials: SG
authors.lastname: Widen
authors.forename: R M
authors.initials: RM
authors.lastname: Goldblum
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D017931:DNA Primers; D004926:Escherichia coli; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011971:Receptors, Immunologic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012635:Secretory Component / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D017931:DNA Primers; D010446:Peptide Fragments; D011971:Receptors, Immunologic; D011994:Recombinant Proteins; D012635:Secretory Component