View source for 8emb


==X-ray crystal structure of Thermosynechococcus elongatus Si3 domain of RNA polymerase RpoC2 subunit==
<StructureSection load='8emb' size='340' side='right'caption='[[8emb]], [[Resolution|resolution]] 3.06&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8emb]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermosynechococcus_vestitus_BP-1 Thermosynechococcus vestitus BP-1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8EMB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8EMB 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]] 3.06&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</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=8emb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8emb OCA], [https://pdbe.org/8emb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8emb RCSB], [https://www.ebi.ac.uk/pdbsum/8emb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8emb ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Cyanobacteria and evolutionarily related chloroplasts of algae and plants possess unique RNA polymerases (RNAPs) with characteristics that distinguish them from canonical bacterial RNAPs. The largest subunit of cyanobacterial RNAP (cyRNAP) is divided into two polypeptides, beta'1 and beta'2, and contains the largest known lineage-specific insertion domain, Si3, located in the middle of the trigger loop and spanning approximately half of the beta'2 subunit. In this study, we present the X-ray crystal structure of Si3 and the cryo-EM structures of the cyRNAP transcription elongation complex plus the NusG factor with and without incoming nucleoside triphosphate (iNTP) bound at the active site. Si3 has a well-ordered and elongated shape that exceeds the length of the main body of cyRNAP, fits into cavities of cyRNAP in the absence of iNTP bound at the active site and shields the binding site of secondary channel-binding proteins such as Gre and DksA. A small transition from the trigger loop to the trigger helix upon iNTP binding results in a large swing motion of Si3; however, this transition does not affect the catalytic activity of cyRNAP due to its minimal contact with cyRNAP, NusG, or DNA. This study provides a structural framework for understanding the evolutionary significance of these features unique to cyRNAP and chloroplast RNAP and may provide insights into the molecular mechanism of transcription in specific environment of photosynthetic organisms and organelle.

Structure and function of the Si3 insertion integrated into the trigger loop/helix of cyanobacterial RNA polymerase.,Qayyum MZ, Imashimizu M, Leanca M, Vishwakarma RK, Riaz-Bradley A, Yuzenkova Y, Murakami KS Proc Natl Acad Sci U S A. 2024 Feb 20;121(8):e2311480121. doi: , 10.1073/pnas.2311480121. Epub 2024 Feb 14. PMID:38354263<ref>PMID:38354263</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 8emb" style="background-color:#fffaf0;"></div>

==See Also==
*[[RNA polymerase 3D structures|RNA polymerase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermosynechococcus vestitus BP-1]]
[[Category: Imashimizu M]]
[[Category: Murakami KS]]
[[Category: Qayyum MZ]]
[[Category: Vishwakarma RK]]
[[Category: Yuzenkova Y]]