title: The region Ser333-Arg356 of the alpha-chain of human C4b-binding protein is involved in the binding of complement C4b.
abstract: Human C4b-binding protein (C4BP) functions as a cofactor to factor I in the degradation of C4b and accelerates the decay rate of the C4b2a complex. In this study we describe a monoclonal antibody directed against the alpha-chain of C4BP that inhibits the binding of C4b to C4BP. In order to identify the structural domain of the alpha-chain of C4BP that interacts with C4b, tryptic fragments of C4BP were generated. Amino acid sequence analysis of the fragments revealed that the residues Ser333-Arg356 of the alpha-chain of C4BP contain the epitope of this antibody, and as a consequence, that this part of the alpha-chain of C4BP is likely to be involved in the interaction with C4b.
authors.affiliation: Department of Haematology, University Hospital Utrecht, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Hessing
authors.forename: D
authors.initials: D
authors.lastname: Kanters
authors.forename: H
authors.initials: H
authors.lastname: Takeya
authors.forename: C
authors.initials: C
authors.lastname: van 't Veer
authors.forename: T M
authors.initials: TM
authors.lastname: Hackeng
authors.forename: S
authors.initials: S
authors.lastname: Iwanaga
authors.forename: B N
authors.initials: BN
authors.lastname: Bouma
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D002352:Carrier Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D015935:Complement C4b / Q000378:metabolism*; D003169:Complement Inactivator Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins; D006801:Humans; D015151:Immunoblotting; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D011951:Receptors, Complement / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D003169:Complement Inactivator Proteins; D006023:Glycoproteins; D011951:Receptors, Complement; D015935:Complement C4b