Electron microscopic visualization of asymmetric precursor translocation intermediates:SecA functions as a dimer

作     者：TAI Phang C 

作者机构：Department of BiologyGeorgia State University 

出 版 物：《Science China(Life Sciences)》 (中国科学（生命科学英文版）)

年 卷 期：2010年第53卷第9期

页      面：1049-1056页

核心收录：

学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 07[理学] 

基　　金：supported by the National Natural Science Foundation of China (Grant No. 30830028) the National Basic Research program of China (Grant No. 2010CD833706/2010CB912400) (S.F.S.) the National Institutes of Health (Grant No. GM34766 to PCT) 

主　　题：SecA SecYEG electron microscopy single particle analysis 

摘      要：SecA,the ATPase of Sec translocase,mediates the post-translational translocation of preprotein through the protein-conduct-ing channel SecYEG in the bacterial inner *** we report the structures of Escherichia coli Sec intermediates during preprotein translocation as visualized by electron microscopy to probe the oligomeric states of SecA during this *** found that the translocase holoenzyme is symmetrically assembled by SecA and SecYEG on proteoliposomes,whereas the translocation intermediate 31 (I31) becomes asymmetric because of the presence of ***,SecA is a dimer in these two translocation *** work also shows surface topological changes in the components of translocation intermediates by immunogold *** channel entry for preprotein translocation was found at the center of the I31 *** results indicate that the presence of preprotein introduces asymmetry into translocation intermediates,while SecA remains dimeric during the translocation process.