View source for 4xej


==IRES bound to bacterial Ribosome==
<StructureSection load='4xej' size='340' side='right'caption='[[4xej]], [[Resolution|resolution]] 3.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4xej]] is a 20 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_thermophilus_HB27 Thermus thermophilus HB27]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4XEJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4XEJ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><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=4xej FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4xej OCA], [https://pdbe.org/4xej PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4xej RCSB], [https://www.ebi.ac.uk/pdbsum/4xej PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4xej ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RL2_THET2 RL2_THET2] One of the primary rRNA binding proteins. 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 somewhat controversial. Makes several contacts with the 16S rRNA in the 70S ribosome (By similarity).
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== Publication Abstract from PubMed ==
The central dogma of gene expression (DNA to RNA to protein) is universal, but in different domains of life there are fundamental mechanistic differences within this pathway. For example, the canonical molecular signals used to initiate protein synthesis in bacteria and eukaryotes are mutually exclusive. However, the core structures and conformational dynamics of ribosomes that are responsible for the translation steps that take place after initiation are ancient and conserved across the domains of life. We wanted to explore whether an undiscovered RNA-based signal might be able to use these conserved features, bypassing mechanisms specific to each domain of life, and initiate protein synthesis in both bacteria and eukaryotes. Although structured internal ribosome entry site (IRES) RNAs can manipulate ribosomes to initiate translation in eukaryotic cells, an analogous RNA structure-based mechanism has not been observed in bacteria. Here we report our discovery that a eukaryotic viral IRES can initiate translation in live bacteria. We solved the crystal structure of this IRES bound to a bacterial ribosome to 3.8 A resolution, revealing that despite differences between bacterial and eukaryotic ribosomes this IRES binds directly to both and occupies the space normally used by transfer RNAs. Initiation in both bacteria and eukaryotes depends on the structure of the IRES RNA, but in bacteria this RNA uses a different mechanism that includes a form of ribosome repositioning after initial recruitment. This IRES RNA bridges billions of years of evolutionary divergence and provides an example of an RNA structure-based translation initiation signal capable of operating in two domains of life.

Initiation of translation in bacteria by a structured eukaryotic IRES RNA.,Colussi TM, Costantino DA, Zhu J, Donohue JP, Korostelev AA, Jaafar ZA, Plank TD, Noller HF, Kieft JS Nature. 2015 Feb 4. doi: 10.1038/nature14219. PMID:25652826<ref>PMID:25652826</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 4xej" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribosomal protein THX 3D structures|Ribosomal protein THX 3D structures]]
*[[Ribosome 3D structures|Ribosome 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermus thermophilus HB27]]
[[Category: Donohue JP]]
[[Category: Korostelev A]]
[[Category: Noller HF]]
[[Category: Zhu J]]