Cotranslational folding of membrane proteins probed by arrest-peptide-mediated force measurements
Cotranslational folding of membrane proteins probed by arrest-peptide-mediated force measurements
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DOI：
10.1073/pnas.1306787110
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发表时间：
2013-09-03
影响因子：
11.1
通讯作者：
von Heijne, Gunnar
中科院分区：
文献类型：
--
作者：
Cymer, Florian;von Heijne, Gunnar
多位膜蛋白通过核糖体-转位子复合物协同插入靶膜。然而，目前尚不清楚在插入过程中，跨膜螺旋之间的特定相互作用何时开始形成。在这里，我们使用最近开发的体内技术来测量跨膜螺旋的共翻译插入到大肠杆菌内膜的过程中作用于跨膜螺旋的拉力，以研究五个多位膜蛋白三级折叠的最早步骤。我们发现，在一个C-末端位于跨膜螺旋和更多的N-末端位于螺旋的残基之间的相互作用，可以检测到已经在点时，C-末端螺旋分区从translocon到膜。我们的研究结果指出了三级结构形成的最早步骤，并开辟了研究多位膜蛋白共翻译折叠的可能性。
Polytopic membrane proteins are inserted cotranslationally into target membranes by ribosome-translocon complexes. It is, however, unclear when during the insertion process specific interactions between the transmembrane helices start to form. Here, we use a recently developed in vivo technique to measure pulling forces acting on transmembrane helices during their cotranslational insertion into the inner membrane of Escherichia coli to study the earliest steps of tertiary folding of five polytopic membrane proteins. We find that interactions between residues in a C-terminally located transmembrane helix and in more N-terminally located helices can be detected already at the point when the C-terminal helix partitions from the translocon into the membrane. Our findings pinpoint the earliest steps of tertiary structure formation and open up possibilities to study the cotranslational folding of polytopic membrane proteins.