TCB Publications - Abstract

Thomas Becker, Shashi Bhushan, Alexander Jarasch, Jean-Paul Armache, Soledad Funes, Fabrice Jossinet, James Gumbart, Thorsten Mielke, Otto Berninghausen, Klaus Schulten, Eric Westhof, Reid Gilmore, Elisabet C. Mandon, and Roland Beckmann. Structure of monomeric yeast and mammalian Sec61 complexes interacting with the translating ribosome. Science, 326:1369-1373, 2009. (PMC: 2920595)

BECK2009 The trimeric Sec61/SecY complex is serving a vital function as a protein-conducting channel (PCC) for secretory and membrane proteins. Although Sec complexes can form oligomers, the crystal structures of prokaryotic SecY complexes and other data suggest that a single copy may serve as an active PCC. Here, we present sub-nanometer resolution cryo-EM structures of eukaryotic ribosome-Sec61 complexes in combination with biochemical data demonstrating that in both states, idle and active, the Sec complex is non-oligomeric and interacts mainly via loop 8 with the universal ribosomal adaptor site. In the active state the ribosomal tunnel and a central pore of the monomeric PCC are occupied by the nascent chain contacting loop 6 of the Sec complex. Our findings provide the structural basis for understanding the activity of a solitary Sec complex in cotranslational translocation.

Download Full Text

The manuscripts available on our site are provided for your personal use only and may not be retransmitted or redistributed without written permissions from the paper's publisher and author. You may not upload any of this site's material to any public server, on-line service, network, or bulletin board without prior written permission from the publisher and author. You may not make copies for any commercial purpose. Reproduction or storage of materials retrieved from this web site is subject to the U.S. Copyright Act of 1976, Title 17 U.S.C.

Download full text: Journal, Request a Copy