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Three-dimensional structure of the bacterial protein-translocation complex SecYEG

Nature volume 418, pages 662–665 (2002)Cite this article

Abstract

Transport and membrane integration of polypeptides is carried out by specific protein complexes in the membranes of all living cells. The Sec transport path provides an essential and ubiquitous route for protein translocation1. In the bacterial cytoplasmic membrane, the channel is formed by oligomers of a heterotrimeric membrane protein complex consisting of subunits SecY, SecE and SecG2,3. In the endoplasmic reticulum membrane, the channel is formed from the related Sec61 complex4. Here we report the structure of the Escherichia coli SecYEG assembly at an in-plane resolution of 8 Å. The three-dimensional map, calculated from two-dimensional SecYEG crystals, reveals a sandwich of two membranes interacting through the extensive cytoplasmic domains. Each membrane is composed of dimers of SecYEG. The monomeric complex contains 15 transmembrane helices. In the centre of the dimer we observe a 16 × 25 Å cavity closed on the periplasmic side by two highly tilted transmembrane helices. This may represent the closed state of the protein-conducting channel.

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Figure 1: Double membrane crystal of SecYEG.
Figure 2: Immunogold labelling with antibodies directed against C-terminal fragments of SecG (b–d) or of SecY (a and e).
Figure 3: Dimeric structure of the SecYEG complex.

References

  1. Matlack, K., Mothes, W. & Rapoport, T. Protein translocation: tunnel vision. Cell 92, 381–390 (1998)

    Article  CAS  Google Scholar 

  2. Brundage, L., Hendrick, J. P., Schiebel, E., Driessen, A. J. & Wickner, W. The purified E. coli integral membrane protein SecY/E is sufficient for reconstitution of SecA-dependent precursor protein translocation. Cell 62, 649–657 (1990)

    Article  CAS  Google Scholar 

  3. Akimaru, J., Matsuyama, S. I., Tokuda, H. & Mizushima, S. Reconstitution of a protein translocation system containing purified SecY, SecE, and SecA from Escherichia coli. Proc. Natl Acad. Sci. USA 88, 6545–6549 (1991)

    Article  ADS  CAS  Google Scholar 

  4. Gorlich, D., Prehn, S., Hartmann, E., Kalies, K. & Rapoport, T. A. A mammalian homolog of SEC61p and SECYp is associated with ribosomes and nascent polypeptides during translocation. Cell 71, 489–503 (1992)

    Article  CAS  Google Scholar 

  5. Hanein, D. et al. Oligomeric ring of the Sec61p complex induced by ligands required for protein translocation. Cell 87, 721–732 (1996)

    Article  CAS  Google Scholar 

  6. Ménétret, J.-F. et al. The structure of ribosome–channel complexes engaged in protein translocation. Mol. Cell 6, 1219–1232 (2000)

    Article  Google Scholar 

  7. Beckmann, R. et al. Architecture of the protein-conducting channel associated with the translocating 80S ribosome. Cell 107, 361–372 (2001)

    Article  CAS  Google Scholar 

  8. Manting, E., van der Does, C., Remigy, H., Engel, A. & Driessen, A. J. M. SecYEG assembles into a tetramer to form the active protein translocation channel. EMBO J. 19, 852–861 (2000)

    Article  CAS  Google Scholar 

  9. Collinson, I. et al. Projection structure and oligomeric properties of a bacterial core protein translocase. EMBO J. 20, 2462–2471 (2001)

    Article  CAS  Google Scholar 

  10. Nishiyama, K., Suzuki, T. & Tokuda, H. Inversion of the membrane topology of SecG coupled with SecA-dependent preprotein translocation. Cell 85, 71–81 (1996)

    Article  CAS  Google Scholar 

  11. Akiyama, Y. & Ito, K. Topology analysis of the SecY protein, an integral membrane protein involved in protein export in Escherichia coli. EMBO J. 6, 3465–3470 (1987)

    Article  CAS  Google Scholar 

  12. Duong, F. & Wickner, W. Distinct catalytic roles of the SecYE, SecG and SecDFyajC subunits of preprotein translocase holoenzyme. EMBO J. 16, 2756–2768 (1997)

    Article  CAS  Google Scholar 

  13. Nishiyama, K., Hanada, M. & Tokuda, H. Disruption of the gene encoding p12 (SecG) reveals the direct involvement and important function of SecG in the protein translocation of Escherichia coli at low temperature. EMBO J. 13, 3272–3277 (1994)

    Article  CAS  Google Scholar 

  14. Bessonneau, P., Besson, V., Collinson, I. & Duong, F. The SecYEG preprotein translocation channel is a conformationally dynamic and dimeric structure. EMBO J. 21, 995–1003 (2002)

    Article  CAS  Google Scholar 

  15. Kaufmann, A., Manting, E. H., Veenendaal, A. K., Driessen, A. J. & van der Does, C. Cysteine-directed cross-linking demonstrates that helix 3 of SecE is close to helix 2 of SecY and helix 3 of a neighbouring SecE. Biochemistry 38, 9115–9125 (1999)

    Article  CAS  Google Scholar 

  16. Flower, A. M., Osborne, R. S. & Silhavy, T. J. The allele-specific synthetic lethality of prlA-prlG double mutants predicts interactive domains of SecY and SecE. EMBO J. 14, 884–893 (1995)

    Article  CAS  Google Scholar 

  17. Plath, K., Mothes, W., Wilkinson, B. M., Stirling, C. J. & Rapoport, T. A. Signal sequence recognition in posttranslational protein transport across the yeast ER membrane. Cell 94, 795–807 (1998)

    Article  CAS  Google Scholar 

  18. Veenendaal, A. K., van der Does, C. & Driessen, A. J. Mapping the sites of interaction between SecY and SecE by cysteine scanning mutagenesis. J. Biol. Chem. 276, 32559–32566 (2001)

    Article  CAS  Google Scholar 

  19. Economou, A. & Wickner, W. SecA promotes preprotein translocation by undergoing ATP-driven cycles of membrane insertion and deinsertion. Cell 78, 835–843 (1994)

    Article  CAS  Google Scholar 

  20. van der Wolk, J. P., de Wit, J. G. & Driessen, A. J. The catalytic cycle of the Escherichia coli SecA ATPase comprises two distinct preprotein translocation events. EMBO J. 16, 7297–7304 (1997)

    Article  CAS  Google Scholar 

  21. Eichler, J., Brunner, J. & Wickner, W. The protease-protected 30 kDa domain of SecA is largely inaccessible to the membrane lipid phase. EMBO J. 16, 2188–2196 (1997)

    Article  CAS  Google Scholar 

  22. Shilton, B. et al. Escherichia coli SecA shape and dimensions. FEBS Lett. 436, 277–282 (1998)

    Article  ADS  CAS  Google Scholar 

  23. Kleymann, G., Ostermeier, C., Heitmann, K., Haase, W. & Michel, H. Use of antibody fragments (Fv) in immunocytochemistry. J. Histochem. Cytochem. 43, 607–614 (1995)

    Article  CAS  Google Scholar 

  24. Fujimoto, K. SDS-digested freeze-fracture replica labeling electron microscopy to study the two-dimensional distribution of integral membrane proteins and phospholipids in biomembranes: practical procedure, interpretation and application. Histochem. Cell Biol. 107, 87–96 (1997)

    Article  CAS  Google Scholar 

  25. Henderson, R., Baldwin, J. M., Downing, K. H. & Zemlin, F. Structure of purple membrane from Halobacterium halobium. Recording, measurement and evaluation of electron micrographs at 3.5 Å resolution. Ultramicroscopy 19, 147–178 (1986)

    Article  CAS  Google Scholar 

  26. Crowther, R. A., Henderson, R. & Smith, J. M. MRC image processing programs. J. Struct. Biol. 116, 9–16 (1996)

    Article  CAS  Google Scholar 

  27. Grigorieff, N., Ceska, T. A., Downing, K. H., Baldwin, J. M. & Henderson, R. Electron-crystallographic refinement of the structure of bacteriorhodopsin. J. Mol. Biol. 259, 393–421 (1996)

    Article  CAS  Google Scholar 

  28. Unger, V. M. Assessment of electron crystallographic data obtained from two-dimensional crystals of biological specimens. Acta Crystallogr. D 56, 1259–1269 (2000)

    Article  CAS  Google Scholar 

  29. Collaborative Computational Project No. 4. The CCP4 suite: programs for protein crystallography. Acta Crystallogr. D 50, 760–763 (1994)

    Article  Google Scholar 

  30. Jones, T. A., Zou, J. Y., Cowans, S. W. & Kjeldgaard, M. Improved methods for building protein models in electron density maps. Acta Crystallogr. 47, 110–119 (1991)

    Article  Google Scholar 

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Acknowledgements

We thank E. Or for the production of the polyclonal antibodies, F. Joos for immunostaining of thin sections, and F. Duong for critically reading the manuscript. C.B. is grateful to D. Mills for help with the JEOL3000SFF electron microscope, V. Unger for advice on image processing, J. Vonck for discussions on noncrystallographic symmetry, and D. Picot for discussions and advice on crystallographic programs. I.C. was a fellow of the Human Frontiers Science Program at Harvard University. C.B. acknowledges support from Jean-Luc Popot and the CNRS-UMR7099, where she carried out the final part of the analysis.

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Authors and Affiliations

  1. Max-Planck-Institut für Biophysik, Abteilung Strukturbiologie, Heinrich-Hoffmann-Straße 7, 60528, Frankfurt am Main, Germany

    Cécile Breyton, Winfried Haase, Werner Kühlbrandt & Ian Collinson

  2. Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Massachusetts, 02115, Boston, USA

    Tom A. Rapoport & Ian Collinson

  3. CNRS-UMR7099, IBPC, 13 rue P. et M. Curie, 75005, Paris, France

    Cécile Breyton

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  1. Cécile Breyton
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Correspondence to Cécile Breyton or Ian Collinson.

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Breyton, C., Haase, W., Rapoport, T. et al. Three-dimensional structure of the bacterial protein-translocation complex SecYEG. Nature 418, 662–665 (2002). https://doi.org/10.1038/nature00827

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