| Title | Structure of the substrate-engaged SecA-SecY protein translocation machine |
| Authors | Ma, Chengying Wu, Xiaofei Sun, Dongjie Park, Eunyong Catipovic, Marco A. Rapoport, Tom A. Gao, Ning Li, Long |
| Affiliation | Peking Univ, Sch Life Sci, Peking Tsinghua Ctr Life Sci, State Key Lab Membrane Biol, Beijing, Peoples R China Univ Calif Berkeley, Stanley Hall, Berkeley, CA 94720 USA Howard Hughes Med Inst, Dept Cell Biol, 240 Longwood Ave, Boston, MA 02115 USA Harvard Med Sch, 240 Longwood Ave, Boston, MA 02115 USA |
| Issue Date | 2019 |
| Publisher | NATURE COMMUNICATIONS |
| Abstract | The Sec61/SecY channel allows the translocation of many proteins across the eukaryotic endoplasmic reticulum membrane or the prokaryotic plasma membrane. In bacteria, most secretory proteins are transported post-translationally through the SecY channel by the SecA ATPase. How a polypeptide is moved through the SecA-SecY complex is poorly understood, as structural information is lacking. Here, we report an electron cryo-microscopy (cryo-EM) structure of a translocating SecA-SecY complex in a lipid environment. The translocating polypeptide chain can be traced through both SecA and SecY. In the captured transition state of ATP hydrolysis, SecA's two-helix finger is close to the polypeptide, while SecA's clamp interacts with the polypeptide in a sequence-independent manner by inducing a short beta-strand. Taking into account previous biochemical and biophysical data, our structure is consistent with a model in which the two-helix finger and clamp cooperate during the ATPase cycle to move a polypeptide through the channel. |
| URI | http://hdl.handle.net/20.500.11897/547329 |
| ISSN | 2041-1723 |
| DOI | 10.1038/s41467-019-10918-2 |
| Indexed | SCI(E) EI |
| Appears in Collections: | 生命科学学院 膜生物学国家重点实验室 |
