Structure of the SecY complex unlocked by a preprotein mimic.
Structure of the SecY complex unlocked by a preprotein mimic.
复制标题
DOI：
10.1016/j.celrep.2011.11.003
复制
发表时间：
2012-01-26
期刊：
影响因子：
8.8
通讯作者：
Collinson I
中科院分区：
文献类型：
--
作者：
Hizlan D;Robson A;Whitehouse S;Gold VA;Vonck J;Mills D;Kühlbrandt W;Collinson I
Sec复合物形成协调蛋白质穿过或进入生物膜的保守机制的核心。细菌复合物SecYEG与ATP酶SecA或翻译核糖体相互作用以相应地易位分泌蛋白和膜蛋白。截短的前蛋白与生理全长底物竞争，并启动蛋白质通道复合物进行转运。我们采用二维晶体的电子低温显微镜来确定由前蛋白解锁的复合物的结构。它在膜的天然环境中的可视化保留了SecYEG二聚体的活性排列，其中两个通道中只有一个被多肽底物占据。信号序列可以沿着SecY中相应的构象变化，包括跨膜片段2b和7以及塞子的重新定位，这可能促进通道开放。因此，我们建议，该结构描述了被前蛋白解锁并准备进行蛋白质易位的易位子。膜结合SecYEG复合物的结构测定由前蛋白解锁SecYEG二聚体仅结合一种底物多肽信号序列结合在SecYEG和脂质双层之间的界面上该缔合传递构象变化，使通道开放蛋白质易位领域的一个主要突出问题在于活性蛋白质通道与其底物接合时的性质。Hizlan等人描述了在膜的天然环境中与一种真正的分泌前蛋白模拟物相关的普遍存在的Sec复合物的结构。结果揭示了信号序列的结合如何在通道开放和前蛋白运输之前解锁Sec复合物。
The Sec complex forms the core of a conserved machinery coordinating the passage of proteins across or into biological membranes. The bacterial complex SecYEG interacts with the ATPase SecA or translating ribosomes to translocate secretory and membrane proteins accordingly. A truncated preprotein competes with the physiological full-length substrate and primes the protein-channel complex for transport. We have employed electron cryomicroscopy of two-dimensional crystals to determine the structure of the complex unlocked by the preprotein. Its visualization in the native environment of the membrane preserves the active arrangement of SecYEG dimers, in which only one of the two channels is occupied by the polypeptide substrate. The signal sequence could be identified along with the corresponding conformational changes in SecY, including relocation of transmembrane segments 2b and 7 as well as the plug, which presumably then promote channel opening. Therefore, we propose that the structure describes the translocon unlocked by preprotein and poised for protein translocation. ► Structure determination of the membrane-bound SecYEG complex unlocked by preprotein ► The SecYEG dimer binds only one substrate polypeptide ► Signal sequence binds at the interface between SecYEG and the lipid bilayer ► The association transmits a conformational change enabling channel opening A major outstanding question in the protein translocation field lies in the nature of the active protein channel upon engagement with its substrate. Hizlan et al. describe the structure of the ubiquitous Sec complex associated with a bone fide mimic of a presecretory protein in the native environment of the membrane. The results reveal how the binding of the signal sequence unlocks the Sec complex prior to channel opening and preprotein transport.
登录
查看更多内容
DOI：
10.1083/jcb.200412019
发表时间：
2005-04-25
期刊：
The Journal of cell biology
影响因子：
--
作者：
Cannon KS;Or E;Clemons WM Jr;Shibata Y;Rapoport TA
通讯作者：
Rapoport TA
DOI：
10.1074/jbc.m110.175638
发表时间：
2011-02-11
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Deville K;Gold VA;Robson A;Whitehouse S;Sessions RB;Baldwin SA;Radford SE;Collinson I
通讯作者：
Collinson I
影响因子：
64.8
作者：
通讯作者：
--
影响因子：
3.2
作者：
Smith, MA;Clemons, WM;Flower, AM
通讯作者：
Flower, AM
影响因子：
64.8
作者：
Park, Eunyong;Rapoport, Tom A.
通讯作者：
Rapoport, Tom A.