A Caltech Library Service

X-ray structure of a protein-conducting channel

van den Berg, Bert and Clemons, William M., Jr. and Collinson, Ian and Modis, Yorgo and Hartmann, Enno and Harrison, Stephen C. and Rapoport, Tom A. (2004) X-ray structure of a protein-conducting channel. Nature, 427 (6969). pp. 36-44. ISSN 0028-0836.

[img] Rich Text (RTF) (Supplementary Figure 1: Sequence alignments.) - Supplemental Material
See Usage Policy.

[img] Rich Text (RTF) (Supplementary Figure Legends) - Supplemental Material
See Usage Policy.

[img] Rich Text (RTF) (Supplementary Methods References) - Supplemental Material
See Usage Policy.

[img] Rich Text (RTF) (Supplementary Table) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Supplementary Figure 2: Overlay of the wild type and mutant crystal forms) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Supplementary Figure 3: Electron density maps) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Supplementary Figure 4: Cα trace of the subunits of the SecY complex) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Supplementary Figure 5: Internal symmetry of the α-subunit) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Supplementary Figure 6: Position of highly conserved amino acid residues) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


A conserved heterotrimeric membrane protein complex, the Sec61 or SecY complex, forms a protein-conducting channel, allowing polypeptides to be transferred across or integrated into membranes. We report the crystal structure of the complex from Methanococcus jannaschii at a resolution of 3.2 Å. The structure suggests that one copy of the heterotrimer serves as a functional translocation channel. The α-subunit has two linked halves, transmembrane segments 1–5 and 6–10, clamped together by the γ-subunit. A cytoplasmic funnel leading into the channel is plugged by a short helix. Plug displacement can open the channel into an ‘hourglass’ with a ring of hydrophobic residues at its constriction. This ring may form a seal around the translocating polypeptide, hindering the permeation of other molecules. The structure also suggests mechanisms for signal-sequence recognition and for the lateral exit of transmembrane segments of nascent membrane proteins into lipid, and indicates binding sites for partners that provide the driving force for translocation.

Item Type:Article
Related URLs:
URLURL TypeDescription ReadCube access
Clemons, William M., Jr.0000-0002-0021-889X
Additional Information:© 2004 Nature Publishing Group. Received 14 October; accepted 19 November 2003; Published online 3 December 2003. We thank R. MacKinnon for advice and suggestions of reagents; F. Duong for clones; J. Walker for C43 cells; C. Vonrhein, T. Terwilliger and K. Cowtan for help with software; M. Becker, L. Berman and S. LaMarra for support at beamline X25 at the National Synchrotron Light Source (Brookhaven National Laboratory, supported by the US Department of Energy, Division of Materials Sciences and Division of Chemical Sciences); A. Joachimiak, S. Ginell and R. Alkire for help at beamline 19ID at the Advanced Photon Source (supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences); and C. Ogata and M. Capel for help at beamline 8BM at the Advanced Photon Source (Northeastern Collaborative Access Team supported by an award from the National Center for Research Resources at the National Institutes of Health). We thank C. Akey, V. Ramakrishnan and particularly K. Matlack for critical reading of the manuscript. This work was supported by a fellowship from the Damon Runyon Cancer Research Foundation to W.M.C., and by fellowships from the Human Frontier Science Program Organization to I.C. and Y.M. E.H. was supported by grants from the Deutsche Forschungsgemeinschaft and Fonds der Chemischen Industrie. T.A.R and S.C.H. are Howard Hughes Medical Institute Investigators.
Funding AgencyGrant Number
Department of Energy (DOE)UNSPECIFIED
Damon Runyon Cancer Research FoundationUNSPECIFIED
Human Frontier Science ProgramUNSPECIFIED
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
Fonds der Chemischen IndustrieUNSPECIFIED
Howard Hughes Medical Institute (HHMI)UNSPECIFIED
Issue or Number:6969
Record Number:CaltechAUTHORS:20181030-134119912
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90517
Deposited By: George Porter
Deposited On:30 Oct 2018 20:54
Last Modified:03 Oct 2019 20:26

Repository Staff Only: item control page