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==== | ==Cryo-EM structure of an Escherichia coli coupled transcription-translation complex B3 (TTC-B3) containing an mRNA with a 24 nt long spacer, transcription factors NusA and NusG, and fMet-tRNAs at P-site and E-site== | ||
<StructureSection load='6x7k' size='340' side='right'caption='[[6x7k]]' scene=''> | <StructureSection load='6x7k' size='340' side='right'caption='[[6x7k]], [[Resolution|resolution]] 3.10Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id= OCA]. For a <b>guided tour on the structure components</b> use [ | <table><tr><td colspan='2'>[[6x7k]] is a 11 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=6X7K OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6X7K FirstGlance]. <br> | ||
</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[ | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.1Å</td></tr> | ||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><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=6x7k FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6x7k OCA], [https://pdbe.org/6x7k PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6x7k RCSB], [https://www.ebi.ac.uk/pdbsum/6x7k PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6x7k ProSAT]</span></td></tr> | |||
</table> | </table> | ||
== Function == | |||
[https://www.uniprot.org/uniprot/RL22_ECOLI RL22_ECOLI] This protein binds specifically to 23S rRNA; its binding is stimulated by other ribosomal proteins, e.g. L4, L17, and L20. It is important during the early stages of 50S assembly. It makes multiple contacts with different domains of the 23S rRNA in the assembled 50S subunit and ribosome.[HAMAP-Rule:MF_01331_B] The globular domain of the protein is one of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit, while an extended beta-hairpin is found that penetrates into the center of the 70S ribosome where it lines the wall of the exit tunnel. Removal of most of this hairpin (residues 85-95) does not prevent its incorporation into 70S ribosomes. Two of the hairpin residues (91 and 93) seem to be involved in translation elongation arrest of the SecM protein, as their replacement by larger amino acids alleviates the arrest.[HAMAP-Rule:MF_01331_B] | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
In bacteria, transcription and translation are coupled processes in which the movement of RNA polymerase (RNAP)-synthesizing messenger RNA (mRNA) is coordinated with the movement of the first ribosome-translating mRNA. Coupling is modulated by the transcription factors NusG (which is thought to bridge RNAP and the ribosome) and NusA. Here, we report cryo-electron microscopy structures of Escherichia coli transcription-translation complexes (TTCs) containing different-length mRNA spacers between RNAP and the ribosome active-center P site. Structures of TTCs containing short spacers show a state incompatible with NusG bridging and NusA binding (TTC-A, previously termed "expressome"). Structures of TTCs containing longer spacers reveal a new state compatible with NusG bridging and NusA binding (TTC-B) and reveal how NusG bridges and NusA binds. We propose that TTC-B mediates NusG- and NusA-dependent transcription-translation coupling. | |||
Structural basis of transcription-translation coupling.,Wang C, Molodtsov V, Firlar E, Kaelber JT, Blaha G, Su M, Ebright RH Science. 2020 Sep 11;369(6509):1359-1365. doi: 10.1126/science.abb5317. Epub 2020, Aug 20. PMID:32820061<ref>PMID:32820061</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 6x7k" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[RNA polymerase 3D structures|RNA polymerase 3D structures]] | |||
*[[Ribosome 3D structures|Ribosome 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Escherichia coli]] | |||
[[Category: Large Structures]] | [[Category: Large Structures]] | ||
[[Category: | [[Category: Ebright RH]] | ||
[[Category: Molodtsov V]] | |||
[[Category: Su M]] | |||
[[Category: Wang C]] | |||
Latest revision as of 16:17, 6 November 2024
Cryo-EM structure of an Escherichia coli coupled transcription-translation complex B3 (TTC-B3) containing an mRNA with a 24 nt long spacer, transcription factors NusA and NusG, and fMet-tRNAs at P-site and E-siteCryo-EM structure of an Escherichia coli coupled transcription-translation complex B3 (TTC-B3) containing an mRNA with a 24 nt long spacer, transcription factors NusA and NusG, and fMet-tRNAs at P-site and E-site
Structural highlights
FunctionRL22_ECOLI This protein binds specifically to 23S rRNA; its binding is stimulated by other ribosomal proteins, e.g. L4, L17, and L20. It is important during the early stages of 50S assembly. It makes multiple contacts with different domains of the 23S rRNA in the assembled 50S subunit and ribosome.[HAMAP-Rule:MF_01331_B] The globular domain of the protein is one of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit, while an extended beta-hairpin is found that penetrates into the center of the 70S ribosome where it lines the wall of the exit tunnel. Removal of most of this hairpin (residues 85-95) does not prevent its incorporation into 70S ribosomes. Two of the hairpin residues (91 and 93) seem to be involved in translation elongation arrest of the SecM protein, as their replacement by larger amino acids alleviates the arrest.[HAMAP-Rule:MF_01331_B] Publication Abstract from PubMedIn bacteria, transcription and translation are coupled processes in which the movement of RNA polymerase (RNAP)-synthesizing messenger RNA (mRNA) is coordinated with the movement of the first ribosome-translating mRNA. Coupling is modulated by the transcription factors NusG (which is thought to bridge RNAP and the ribosome) and NusA. Here, we report cryo-electron microscopy structures of Escherichia coli transcription-translation complexes (TTCs) containing different-length mRNA spacers between RNAP and the ribosome active-center P site. Structures of TTCs containing short spacers show a state incompatible with NusG bridging and NusA binding (TTC-A, previously termed "expressome"). Structures of TTCs containing longer spacers reveal a new state compatible with NusG bridging and NusA binding (TTC-B) and reveal how NusG bridges and NusA binds. We propose that TTC-B mediates NusG- and NusA-dependent transcription-translation coupling. Structural basis of transcription-translation coupling.,Wang C, Molodtsov V, Firlar E, Kaelber JT, Blaha G, Su M, Ebright RH Science. 2020 Sep 11;369(6509):1359-1365. doi: 10.1126/science.abb5317. Epub 2020, Aug 20. PMID:32820061[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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