View source for 7rdq


==Cryo-EM structure of Thermus thermophilus reiterative transcription complex with 11nt oligo-G RNA==
<StructureSection load='7rdq' size='340' side='right'caption='[[7rdq]], [[Resolution|resolution]] 3.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7rdq]] is a 9 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_thermophilus_HB8 Thermus thermophilus HB8] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7RDQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7RDQ 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]] 3&#8491;</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=7rdq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7rdq OCA], [https://pdbe.org/7rdq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7rdq RCSB], [https://www.ebi.ac.uk/pdbsum/7rdq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7rdq ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RPOA_THET8 RPOA_THET8] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Reiterative transcription initiation, observed at promoters that contain homopolymeric sequences at the transcription start site, generates RNA products having 5' sequences noncomplementary to the DNA template. Here, using crystallography and cryoelectron microscopy to define structures, protein-DNA photocrosslinking to map positions of RNAP leading and trailing edges relative to DNA, and single-molecule DNA nanomanipulation to assess RNA polymerase (RNAP)-dependent DNA unwinding, we show that RNA extension in reiterative transcription initiation 1) occurs without DNA scrunching; 2) involves a short, 2- to 3-bp, RNA-DNA hybrid; and 3) generates RNA that exits RNAP through the portal by which scrunched nontemplate-strand DNA exits RNAP in standard transcription initiation. The results establish that, whereas RNA extension in standard transcription initiation proceeds through a scrunching mechanism, RNA extension in reiterative transcription initiation proceeds through a slippage mechanism, with slipping of RNA relative to DNA within a short RNA-DNA hybrid, and with extrusion of RNA from RNAP through an alternative RNA exit.

Structural and mechanistic basis of reiterative transcription initiation.,Liu Y, Yu L, Pukhrambam C, Winkelman JT, Firlar E, Kaelber JT, Zhang Y, Nickels BE, Ebright RH Proc Natl Acad Sci U S A. 2022 Feb 1;119(5):e2115746119. doi: , 10.1073/pnas.2115746119. PMID:35082149<ref>PMID:35082149</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7rdq" style="background-color:#fffaf0;"></div>

==See Also==
*[[RNA polymerase 3D structures|RNA polymerase 3D structures]]
*[[Sigma factor 3D structures|Sigma factor 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Thermus thermophilus HB8]]
[[Category: Ebright RH]]
[[Category: Liu Y]]