期刊名称：Fibre Diffraction Review : the CCP13 Newsletter ; Software Development for Fibre Diffraction (Formerly The CCP13 Newsletter)
印刷版ISSN：1463-8401
电子版ISSN：1463-8401
出版年度：2002
卷号：10
出版社：CCLRC Daresbury Laboratory
摘要：Factor H (FH) of the complement system of immune
defence is present in plasma at about 0.5 mg/ml. It
consists entirely of 20 short complement/consensus
repeat (SCR) domains, each of length about 61
residues, where SCR domains constitute the most
abundant domain type in the complement proteins.
The principal function of FH is to regulate the
alternative pathway of complement activation by
acting as a cofactor for factor I in the breakdown of
C3b to form iC3b. The cofactor and decay
accelerating activity are located within the four Nterminal
domains, SCR-1 to SCR-4, which bind to
intact C3b. A second C3 site is located within SCR-
6 to SCR-10 which binds to the C3c region of C3b,
and a third site is located within SCR-16 and SCR-
20 which binds to the C3d region of C3b. FH also
binds to heparin and other polyanionic substrates,
where heparin modulates the complement regulatory
functions of FH. Two heparin binding sites have been
located in SCR-7 and SCR-20 in recombinant FH,
and a third heparin binding site is suggested to be
located at or near SCR-13. The SCR domains are
thought to act synergistically to enable FH to achieve
differential control of complement activation.
