The region Ser333-Arg356 of the alpha-chain of human C4b-binding protein is involved in the binding of complement C4b.
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.
Hessing
M
M
Department of Haematology, University Hospital Utrecht, The Netherlands.
Kanters
D
D
Takeya
H
H
van 't Veer
C
C
Hackeng
T M
TM
Iwanaga
S
S
Bouma
B N
BN
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
D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D003169:Complement Inactivator Proteins; D006023:Glycoproteins; D011951:Receptors, Complement; D015935:Complement C4b