Structural and Functional Analysis of Complement C3/C5 Convertases.

补体 C3/C5 转化酶的结构和功能分析。

• 批准号: 01570233
• 负责人: KINOSHITA Taroh
• 金额: $ 1.34万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01570233/
• 关键词: Complement; Self defense; Immunity

We have analyzed C5 convertase of the classical pathway and the alternative pathway of complement, and obtained following results.(1) Within the classical pathway C5 convertase, C4b2a3b complex, C3b binds to C4b through an ester-linkage. Protein chemical analysis of C4b-C3b complex demonstrated that the C3b-binding site is within a region that spans from Ala 1186 to Lys 1259. Further localization of the binding site was achieved by using mutant C4 proteins prepared by recombinant DNA technology : Ser 1217 was found to be a primary binding site and Ser 1219 to be an alternative site. These results suggest that binding of C3b to C4b is a specific reaction to form a trimolecular complex with defined quaternary structure.(2) C4A6 protein, A mutant C4 that does not form C5 convertase, was analyzed. It was found that C4A6 when activated makes C4b2a3b complex but this complex does not bind C5, indicating C4b also contributes in C5-binding.(3) The alternative pathway C5 convertase was reconstituted from purified C3b dimer and factors B and D. This supports our model of the C5 convertase that holds that the alternative pathway C5 convertase is a trimolecular complex in which Bb binds noncovalently to a covalently linked C3b dimer.

我们分析了补体经典途径和替代途径的C5转化酶，得到了以下结果。(1)在经典途径C5转化酶C4b2a3b复合物中，C3b通过酯链与C4b结合。C4b-C3b复合物的蛋白化学分析表明，c3b结合位点位于Ala 1186 - Lys 1259区域内。利用重组DNA技术制备的突变体C4蛋白实现了结合位点的进一步定位：发现Ser 1217是主要结合位点，Ser 1219是替代位点。这些结果表明，C3b与C4b的结合是形成具有明确的四元结构的三分子复合物的特异性反应。(2)分析了不形成C5转化酶的C4突变体C4A6蛋白。我们发现C4A6在激活时产生C4b2a3b复合物，但该复合物不结合C5，这表明C4b也参与了C5的结合。(3)从纯化的C3b二聚体和因子B和d中重组了替代途径C5转化酶，这支持了我们的C5转化酶模型，即替代途径C5转化酶是一个三分子复合物，其中Bb与共价连接的C3b二聚体非共价结合。

项目成果

Taroh Kinoshita, Alister W. Dodds. S. K. Alex Law and Kozo Inoue.: "The low C5 convertase activity of the C4A6 allotype of human complement component C4." Biochemical Journal. 261. 743-748 (1989)

木下太罗，阿利斯特·W·多兹。

Taroh Kinoshita: "The low C5 convertase activity of the C4A6 allotype of human complement complement component C4" Biochemical Journal. 261. 743-748 (1989)

Taroh Kinoshita：“人补体补体成分 C4 的 C4A6 同种异型的低 C5 转化酶活性”生物化学杂志。

Haruo Kozono: "Localization of covalent C3bーbinding site on C4b within the complement classical pathway C5 convestase,C4b2a3b." Journal of Biological Chemistry.265. (1990)

Haruo Kozono：“补体经典途径 C5 转换酶中 C4b 上的共价 C3b 结合位点的定位，C4b2a3b。”《生物化学杂志》(1990)。

Kyoungsu Hong.: "Reconstitution of C5 convertase of the alternative complement pathway with isalation C3d dimer and facter B and C." Journal of Imminology. 146. (1991)

Kyoungsu Hong.：“用隔离 C3d 二聚体和因子 B 和 C 重建替代补体途径的 C5 转化酶。”

K.メンエキ14444-14449

K·梅内基 14444-14449