View source for 5abb


==Visualization of a polytopic membrane protein during SecY-mediated membrane insertion==
<SX load='5abb' size='340' side='right' viewer='molstar' caption='[[5abb]], [[Resolution|resolution]] 8.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5abb]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5ABB OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5ABB FirstGlance]. <br>
</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5abb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5abb OCA], [http://pdbe.org/5abb PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5abb RCSB], [http://www.ebi.ac.uk/pdbsum/5abb PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5abb ProSAT]</span></td></tr>
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== Function ==
[[http://www.uniprot.org/uniprot/B7MCR5_ECO45 B7MCR5_ECO45]] The central subunit of the protein translocation channel SecYEG. Consists of two halves formed by TMs 1-5 and 6-10. These two domains form a lateral gate at the front which open onto the bilayer between TMs 2 and 7, and are clamped together by SecE at the back. The channel is closed by both a pore ring composed of hydrophobic SecY resides and a short helix (helix 2A) on the extracellular side of the membrane which forms a plug. The plug probably moves laterally to allow the channel to open. The ring and the pore may move independently.[HAMAP-Rule:MF_01465][RuleBase:RU000537] [[http://www.uniprot.org/uniprot/PRRG_PRB01 PRRG_PRB01]] Light-driven proton pump that generates photothrophic energy. [[http://www.uniprot.org/uniprot/B7MIW7_ECO45 B7MIW7_ECO45]] Essential subunit of the Sec protein translocation channel SecYEG. Clamps together the 2 halves of SecY. May contact the channel plug during translocation.[HAMAP-Rule:MF_00422] 
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== Publication Abstract from PubMed ==
The biogenesis of polytopic membrane proteins occurs co-translationally on ribosomes that are tightly bound to a membrane-embedded protein-conducting channel: the Sec-complex. The path that is followed by nascent proteins inside the ribosome and the Sec-complex is relatively well established; however, it is not clear what the fate of the N-terminal transmembrane domains (TMDs) of polytopic membrane proteins is when the C-terminal TMDs domains are not yet synthesized. Here, we present the sub-nanometer cryo-electron microscopy structure of an in vivo generated ribosome-SecY complex that carries a membrane insertion intermediate of proteorhodopsin (PR). The structure reveals a pre-opened Sec-complex and the first two TMDs of PR already outside the SecY complex directly in front of its proposed lateral gate. Thus, our structure is in agreement with positioning of N-terminal TMDs at the periphery of SecY, and in addition, it provides clues for the molecular mechanism underlying membrane protein topogenesis.

Visualization of a polytopic membrane protein during SecY-mediated membrane insertion.,Bischoff L, Wickles S, Berninghausen O, van der Sluis EO, Beckmann R Nat Commun. 2014 Jun 10;5:4103. doi: 10.1038/ncomms5103. PMID:24912953<ref>PMID:24912953</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 5abb" style="background-color:#fffaf0;"></div>

==See Also==
*[[Bacteriorhodopsin 3D structures|Bacteriorhodopsin 3D structures]]
*[[Preprotein translocase|Preprotein translocase]]
== References ==
<references/>
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[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Beckmann, R]]
[[Category: Berninghausen, O]]
[[Category: Bischoff, L]]
[[Category: Wickles, S]]
[[Category: VanderSluis, E]]
[[Category: Membrane protein]]
[[Category: Ribosome]]
[[Category: Translation]]
[[Category: Translocon]]