Importance of the α3‐fragment of complement C4 for the binding with C4b‐binding protein

FEBS Letters

van't Veer, Cornells¹  Bouma, Bonno N.¹  Hessing, Martin¹  Iwanaga, Sadaaki²  Hackeng, Tilman M.¹ 

[1] Department of Haematology, University Hospital Utrecht, Utrecht, The Netherlands;Department of Biology, Faculty of Science, Kyushu University 33, Fukuoka 812, Japan

关键词: Complement regulation;    C4b-binding protein;    Complement C4;    C4BP;    C4b-binding protein;    mAb;    monoclonal antibody;    SDS-PAGE;    sodium dodecyl sulfate-polyacrylamide gel electrophoresis;   

DOI  :  10.1016/0014-5793(90)80389-Z

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The human regulatory complement component C4b-binding protein (C4BP) is a multimene plasma protein, which regulates the classical pathway of the complement system. C4BP functions as a cofactor to factor 1 in the degradation of C4b and accelerates the decay rate of the C4b2a complex. Previously, we have demonstrated that monoclonal antibodies (C4-2 and 9) directed against the α'-chain of C4b inhibit the binding of C4b to C4BP. In order to identify the structural domain of C4b that binds C4BP, proteolytic fragments of C4 were generated with trypsin and Staphylococcus aureus V8 protease. Sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblotting and amino acid sequence analysis of the proteolytic fragments reactive with the anti-C4 mAb's revealed that the residues Ala⁷³⁸-Arg⁸²⁶ of the α₃-fragment of C4b are important for the interaction with C4BP.

【 授权许可】

Unknown