Functional properties of complement factor H‐related proteins FHR‐3 and FHR‐4: binding to the C3d region of C3b and differential regulation by heparin

FEBS Letters

Hellwage, Jens²  Jokiranta, T.Sakari²  Zipfel, Peter F.²  Meri, Seppo³  Vaarala, Outi¹  Koistinen, Vesa³ 

[1] Department of Biochemistry, National Public Health Institute, Mannerheimintie 166, FIN-00300 Helsinki, Finland;Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, D-20359 Hamburg, Germany;Haartman Institute and HD-Diagnostics, Department of Bacteriology and Immunology, Haartmaninkatu 3, FIN-00290 Helsinki, Finland

关键词: Complement regulation;    Heparin binding;    Surface plasmon resonance;    Alternative pathway;    Streptococcus pneumoniae;    FH;    complement factor H;    FHDS;    factor H-deficient serum;    FHR-3;    factor H-related protein 3;    FHR-4;    factor H-related protein 4;    SCR;    short consensus repeat;   

DOI  :  10.1016/S0014-5793(99)01554-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The human factor H-related proteins FHR-3 and FHR-4 are members of a family of proteins related to the complement factor H. Here, we report that the two proteins bind to the C3d region of complement C3b. The apparent K _A values for the interactions of FHR-3 and FHR-4 with C3b are 7.5×10⁶ M⁻¹ and 2.9×10⁶ M⁻¹, respectively. Binding studies performed with C3b-coated pneumococci confirmed the results obtained with the biosensor system. A C-terminal construct of factor H showed similar binding characteristics. The interaction of FHR-3, but not of FHR-4, with opsonised pneumococci was inhibited by heparin.

【 授权许可】

Unknown