Plath K, Mothes W, Wilkinson B M, Stirling C J, Rapoport T A
Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Cell. 1998 Sep 18;94(6):795-807. doi: 10.1016/s0092-8674(00)81738-9.
We have analyzed how the signal sequence of prepro-alpha-factor is recognized during the first step of posttranslational protein transport into the yeast endoplasmic reticulum. Cross-linking studies indicate that the signal sequence interacts in a Kar2p- and ATP-independent reaction with Sec61p, the multispanning membrane component of the protein-conducting channel, by intercalation into transmembrane domains 2 and 7. While bound to Sec61p, the signal sequence forms a helix that is contacted on one side by Sec62p and Sec71p. The binding site is located at the interface of the protein channel and the lipid bilayer. Signal sequence recognition in cotranslational translocation in mammals appears to occur similarly. These results suggest a general mechanism by which the signal sequence could open the channel for polypeptide transport.
我们分析了在翻译后蛋白质转运至酵母内质网的第一步过程中，前原α因子的信号序列是如何被识别的。交联研究表明，信号序列通过插入跨膜结构域2和7，以一种不依赖Kar2p和ATP的反应与Sec61p相互作用，Sec61p是蛋白质传导通道的多跨膜膜成分。在与Sec61p结合时，信号序列形成一个螺旋，其一侧与Sec62p和Sec71p接触。结合位点位于蛋白质通道和脂质双层的界面处。哺乳动物共翻译转运中的信号序列识别似乎也以类似方式发生。这些结果提示了一种信号序列可能为多肽转运打开通道的通用机制。
