中文摘要：

CD59 可以由绑定禁止补充的 cytolytic 活动到 C8/C9 并且保护主人房间膜免于相应的膜攻击建筑群(MAC ) 。然而， CD59 是广泛地肿瘤房间上的 overexpressed，它在 tumorigenesis 被含有。相对 MAC 的 CD59 的活跃地点仍然被糊涂。是报导 MAC 有约束力的地点在蛋白质的远侧的脸在残余 W40 附近集中了的膜上位于一条恐水病的沟的附近。这里，二指导地点的 mutagenesis 被重叠延期 PCR 执行删除残余 W40 地点(异种 1， M1 ) 或把 C39W40K41 改变到 W39W40W41 (异种 2， M2 ) 。然后，我们构造了变异的 CD59 真核细胞的表达式系统并且与野类型的 CD59 相比在 CHO 房间上调查了他们的生物函数。表示 recombinant 蛋白质的 CHO 房间的稳定的人口被 immunotechnique 屏蔽。在 30 段落 culturing 以后，蛋白质能被测试。染料版本试金建议 M1CD59 对补充失去这项活动，当 M2CD59 稍微增加反补充活动时。结果显示人的 CD59 的 W40 对它的活动重要，并且这个地点的禁止可以是增加补充活动并且治疗肿瘤的一个潜在的方法。

英文摘要：

CD59 may inhibit the cytolytic activity of complement by binding to C8/C9 and protect host cell membranes against homologous membrane attack complex （MAC）. However, CD59 is widely overexpressed on tumor cells, which has been implicated in tumorigenesis. The active site of CD59 relative to MAC is still confused. As reported the MAC binding site is located in the vicinity of a hydrophobic groove on the membrane distal face of the protein centered around residue W40. Here two site-directed mutagenesis were performed by overlapping extension PCR to delete residue W40 site （Mutant 1, M1） or to change C39W40K41 to W39W40W41 （Mutant 2, M2）. Then we constructed mutant CD59 eukaryotic expression system and investigated their biological function on CI-IO cells compared with wild-type CD59. Stable populations of CHO cells expressing recombinant proteins were screened by immunotechnique. After 30 passages culturing, proteins could be tested. Dye release assays suggest that M1CD59 loses the activity against complement, while M2CD59 increases the anti-complement activity slightly. Results indicate that W40 of human CD59 is important to its activity, and prohibition of this site may be a potential way to increase complement activity and to treat tumors. Cellular ＆ Molecular Immunology.