View source for 5nco


==Quaternary complex between SRP, SR, and SecYEG bound to the translating ribosome==
<SX load='5nco' size='340' side='right' viewer='molstar' caption='[[5nco]], [[Resolution|resolution]] 4.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5nco]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5NCO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5NCO 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]] 4.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ALF:TETRAFLUOROALUMINATE+ION'>ALF</scene>, <scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></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=5nco FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5nco OCA], [https://pdbe.org/5nco PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5nco RCSB], [https://www.ebi.ac.uk/pdbsum/5nco PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5nco ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/RL2_ECOLI RL2_ECOLI] One of the primary rRNA binding proteins. Located near the base of the L1 stalk, it is probably also mobile. Required for association of the 30S and 50S subunits to form the 70S ribosome, for tRNA binding and peptide bond formation. It has been suggested to have peptidyltransferase activity; this is highly controversial.[HAMAP-Rule:MF_01320_B]  In the E.coli 70S ribosome in the initiation state it has been modeled to make several contacts with the 16S rRNA (forming bridge B7b, PubMed:12809609); these contacts are broken in the model with bound EF-G.[HAMAP-Rule:MF_01320_B]
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== Publication Abstract from PubMed ==
During co-translational protein targeting, the signal recognition particle (SRP) binds to the translating ribosome displaying the signal sequence to deliver it to the SRP receptor (SR) on the membrane, where the signal peptide is transferred to the translocon. Using electron cryo-microscopy, we have determined the structure of a quaternary complex of the translating Escherichia coli ribosome, the SRP-SR in the 'activated' state and the translocon. Our structure, supported by biochemical experiments, reveals that the SRP RNA adopts a kinked and untwisted conformation to allow repositioning of the 'activated' SRP-SR complex on the ribosome. In addition, we observe the translocon positioned through interactions with the SR in the vicinity of the ribosome exit tunnel where the signal sequence is extending beyond its hydrophobic binding groove of the SRP M domain towards the translocon. Our study provides new insights into the mechanism of signal sequence transfer from the SRP to the translocon.

Structure of the quaternary complex between SRP, SR, and translocon bound to the translating ribosome.,Jomaa A, Fu YH, Boehringer D, Leibundgut M, Shan SO, Ban N Nat Commun. 2017 May 19;8:15470. doi: 10.1038/ncomms15470. PMID:28524878<ref>PMID:28524878</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 5nco" style="background-color:#fffaf0;"></div>

==See Also==
*[[Signal recognition particle receptor 3D structures|Signal recognition particle receptor 3D structures]]
== References ==
<references/>
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[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Ban N]]
[[Category: Boerhinger D]]
[[Category: Hwang Fu Y]]
[[Category: Jomaa A]]
[[Category: Leibundgut M]]
[[Category: Shan SO]]