STUDIES ON THE STRUCTURE AND FUNCTION OF PERTUSSIS TOXIN

已经开始研究百日咳进入的机制 毒素（PT）进入真核细胞。百日咳毒素的相互作用 与细胞和模型膜进行了研究，通过检查PT诱导 中国仓鼠卵巢（CHO）细胞中毒，并通过研究 PT及其亚基与磷脂囊泡的结合。因为某些 细菌毒素需要酸性环境才能有效地相互作用 与膜和随后进入细胞，需要一个 酸性环境PT行动进行了检查。PT，与细菌不同 毒素如白喉毒素，不需要酸性环境， 用于中国仓鼠卵巢细胞的有效中毒。势模 PT可能与生物膜相互作用的研究， 检查PT与模型膜系统的结合。发现PT为 能够与磷脂囊泡相互作用，但效率 然而，毒素与囊泡的有效结合， 毒素的囊泡只发生在ATP和 还原剂 毒素的A亚单位部分优先结合 而PT的B寡聚体部分几乎不与囊泡结合， 观察模型膜。分离的A亚基，在缺乏 B寡聚体也与囊泡结合，并发生最佳结合 在还原剂的存在下。A亚基裂解后 胰蛋白酶，可能在Arg 181，Arg 182和/或Arg 193，大片段 缺乏PTA的C末端部分，不再与 脂质囊泡。这些结果表明，PT的A亚基可以 直接与脂质基质相互作用，如果不受限制， 由B寡聚体施加的，可能能够与细胞相互作用， 膜。 PT及其B寡聚体与含有 还研究了鞘糖脂。

Studies have been initiated to examine the mechanism of entry of pertussis toxin (PT) into the eukaryotic cell. The interaction of pertussis toxin with cells and model membranes was investigated by examining PT-induced intoxication of Chinese hamster ovary (CHO) cells and by studying the binding of PT and its subunits to phospholipid vesicles. Since certain bacterial toxins require an acidic environment for efficient interaction with membranes and subsequent entry into the cell, the requirement for an acidic environment for PT action was examined. PT, unlike bacterial toxins such as diphtheria toxin, did not require an acidic environment for efficient intoxication of Chinese hamster ovary cells. Potential modes by which PT might interact with biological membranes were studied by examining the binding of PT to model membrane system. PT was found to be capable of interacting with phospholipid vesicles, however efficient binding of the toxin to the vesicles, however, efficient binding of the toxin to the vesicles occurred only in the presence of both ATP and reducing agent. The A subunit portion of the toxin bound preferentially to the vesicles while little binding of the B oligomer portion of PT to the model membranes was observed. Isolated A subunit, in the absence of the B oligomer, also bound to the vesicles with optimal binding occurring in the presence of reducing agent. After cleavage of the A subunit by trypsin, probably at Arg181, Arg182 and/or Arg193, large fragments which lacked the C-terminal portion of PTA no longer associated with the lipid vesicles. These results suggest that the A subunit of PT can interact directly with a lipid matrix and, if freed from the constraints imposed by the B oligomer, may be capable of interacting with cellular membranes. The binding of PT and its B oligomer to lipid vesicles containing glycosphingolipids was also also studied.