The plug domain of the SecY protein stabilizes the closed state of the translocation channel and maintains a membrane seal.

@article{Li2007ThePD,
  title={The plug domain of the SecY protein stabilizes the closed state of the translocation channel and maintains a membrane seal.},
  author={Weikai Li and Sol Schulman and Dana A. M. Boyd and Karl J. Erlandson and Jon et Beckwith and Tom A Rapoport},
  journal={Molecular cell},
  year={2007},
  volume={26 4},
  pages={511-21}
}
Proteins are translocated across membranes through a channel that is formed by the prokaryotic SecY or eukaryotic Sec61 complex. The crystal structure of the SecY channel from M. jannaschii revealed a plug domain that appears to seal the channel in its closed state. However, the role of the plug remains unclear, particularly because plug deletion mutants in S. cerevisiae are functional. Here, we demonstrate that plug deletion mutants in E. coli SecY are also functional and even efficiently… CONTINUE READING