Competition for binding sites on C3b by CR1, CR2, MCP, factor B and factor H.
Competition for binding sites on C3b by CR1, CR2, MCP, factor B and factor H.
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CR1、CR2、MCP、B 因子和 H 因子竞争 C3b 上的结合位点。
DOI：
10.1159/000463124
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Atkinson,JP
中科院分区：
文献类型：
--
作者：
Farries,TC;Seya,T;Harrison,RA;Atkinson,JP
研究了放射性标记的C3b结合蛋白与C3b包被颗粒的反应。CR 1结合被抑制因子H和因子B（在备解素的存在下），但不是单独的备解素。CR2和MCP结合也被因子H抑制。因此，因子H、因子B、CR1、CR2和MCP可能包含一组在C3 B上具有相似或重叠结合位点的相互竞争的蛋白。这些结果与它们的结构同源性相关，并表明它们都是从单个C3b结合分子进化而来的。因子H、CR1和MCP也是因子I介导的C3b裂解的辅因子。大鼠因子I和人CR1对人C3b裂解的种属不相容性表明辅因子也可能通过与因子I直接相互作用而发挥作用。
The reaction of radiolabeled C3b-binding proteins with C3b-coated particles has been investigated. CR1 binding was inhibited by factor H and factor B (in the presence of properdin), but not by properdin alone. CR2 and MCP binding were also inhibited by factor H. Therefore factor H, factor B, CRI, CR2 and MCP probably comprise a group of mutually competitive proteins with similar or overlapping binding sites on C3b. These results correlate with their structural homology and suggest that they all evolved from a single C3b-binding molecule. Factor H, CR1 and MCP are also cofactors for the factor- I-mediated cleavage of C3b. A species incompatibility between rat factor I and human CR1 for the cleavage of human C3b suggests the possibility that cofactors may also function by interacting directly with factor I.