论文部分内容阅读
SecY基因产物是一个整合在膜上的蛋白,从基因角度它已被鉴定为E·Coli蛋白转位机制中主要化合物之一。我们检测了温度敏感型突变株SecY_(100)转化膜的转位活性。发现生长在允许温度下的突变株SecY_(100)的膜具有部分转位活性。若在40℃下预保温75 min则转位活性明显减少,与SecY_(24)的膜相比较,在非允许温度下,SecY_(100)的膜远不如SecY_(24)的膜对排出抑制敏感。我们的结果对SecY在转位过程中的基本作用提供了生化证据。实验表明,体外部分热失活的Secy的膜不可能经过重新保温在允许温度下而恢复其原来的转化活性。
The SecY gene product is a membrane-bound protein that has been identified from the genetic point of view as one of the major compounds in the E. Coli protein translocation machinery. We examined the translocation activity of temperature-sensitive mutant SecY_ (100) transformant. The membrane of mutant strain SecY_ (100) grown at the allowable temperature was found to have partial translocation activity. The translocation activity was significantly reduced at precooling of 40 min at 75 ° C. Compared with the membrane of SecY_ (24), the membrane of SecY_ (100) was far less sensitive to the inhibition of excretion than the membrane of SecY_ (24) . Our results provide biochemical evidence that SecY plays a fundamental role in translocation. Experiments show that in vitro partially inactivated Secy’s membrane can not be re-incubated at the allowable temperature to restore its original conversion activity.