View source for 4cg5


==Cryo-EM of the Sec61-complex bound to the 80S ribosome translating a secretory substrate==
<SX load='4cg5' size='340' side='right' viewer='molstar' caption='[[4cg5]], [[Resolution|resolution]] 7.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4cg5]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Canis_lupus_familiaris Canis lupus familiaris]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4CG5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4CG5 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 7.4&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4cg5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4cg5 OCA], [https://pdbe.org/4cg5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4cg5 RCSB], [https://www.ebi.ac.uk/pdbsum/4cg5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4cg5 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/S61A1_CANLF S61A1_CANLF] 
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== Publication Abstract from PubMed ==
The biogenesis of secretory as well as transmembrane proteins requires the activity of the universally conserved protein-conducting channel (PCC), the Sec61 complex (SecY complex in bacteria). In eukaryotic cells the PCC is located in the membrane of the endoplasmic reticulum where it can bind to translating ribosomes for co-translational protein transport. The Sec complex consists of three subunits (Sec61alpha, beta and gamma) and provides an aqueous environment for the translocation of hydrophilic peptides as well as a lateral opening in the Sec61alpha subunit that has been proposed to act as a gate for the membrane partitioning of hydrophobic domains. A plug helix and a so-called pore ring are believed to seal the PCC against ion flow and are proposed to rearrange for accommodation of translocating peptides. Several crystal and cryo-electron microscopy structures revealed different conformations of closed and partially open Sec61 and SecY complexes. However, in none of these samples has the translocation state been unambiguously defined biochemically. Here we present cryo-electron microscopy structures of ribosome-bound Sec61 complexes engaged in translocation or membrane insertion of nascent peptides. Our data show that a hydrophilic peptide can translocate through the Sec complex with an essentially closed lateral gate and an only slightly rearranged central channel. Membrane insertion of a hydrophobic domain seems to occur with the Sec complex opening the proposed lateral gate while rearranging the plug to maintain an ion permeability barrier. Taken together, we provide a structural model for the basic activities of the Sec61 complex as a protein-conducting channel.

Structures of the Sec61 complex engaged in nascent peptide translocation or membrane insertion.,Gogala M, Becker T, Beatrix B, Armache JP, Barrio-Garcia C, Berninghausen O, Beckmann R Nature. 2014 Feb 6;506(7486):107-10. doi: 10.1038/nature12950. PMID:24499919<ref>PMID:24499919</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 4cg5" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</SX>
[[Category: Canis lupus familiaris]]
[[Category: Large Structures]]
[[Category: Barrio-Garcia C]]
[[Category: Beatrix B]]
[[Category: Becker T]]
[[Category: Beckmann R]]
[[Category: Berninghausen O]]
[[Category: Gogala M]]