麻疯树核糖体失活蛋白的分离纯化和作用机制研究

Isolation, Purification and Functional Investigation on the N-glycosidase Activity of Curcin from the Seeds of Jatropha curcas

从麻疯树种子中分离纯化出一种核糖体失活蛋白 ,用SDS PAGE测定其相对分子量为 2 8 2kD ,IEF PAGE计算其等点电为 8 5 4左右。体外抑制实验表明 ,麻疯树核糖体失活蛋白对兔网织红细胞裂解液的蛋白质生物合成有较强的抑制活性。当麻疯树核糖体失活蛋白作用于大鼠肝核糖体经苯胺处理后 ,在聚丙烯酰胺的尿素变性胶电泳图上能观察到 4 5 0bp左右的特征性核酸条带 ,证明麻疯树核糖体失活蛋白是一种RNAN 糖苷酶 ,从而首次阐明了麻疯树核糖体失活蛋白失活核糖体的分子机制。

A ribosome inactivating protein curcin was isolated from the seeds of Jatropha curcas. The results of SDS PAGE indicate that its molecular weight was around 28.2 kD, and the results of IEF PAGE indicate its isoelectric point was 8.54. The curcin strongly inhibits protein synthesis in ribbit reticulocyte lysate system. When rRNAs were simultanous treated with curcin and aniline, a characteristic fragment of approximant 450 bp was obtained, which reveals that curcin has the activity of RNA N glycosidase indeed. This study reveals for the first time that the functional mechanism of curcin at molecular level.