View source for 7ae3


==Cryo-EM structure of human RNA Polymerase III elongation complex 3==
<StructureSection load='7ae3' size='340' side='right'caption='[[7ae3]], [[Resolution|resolution]] 3.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7ae3]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7AE3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7AE3 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]] 3.1&#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=7ae3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7ae3 OCA], [https://pdbe.org/7ae3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7ae3 RCSB], [https://www.ebi.ac.uk/pdbsum/7ae3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7ae3 ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/RPC2_HUMAN RPC2_HUMAN] Endosteal sclerosis-cerebellar hypoplasia syndrome;Hypomyelination-hypogonadotropic hypogonadism-hypodontia syndrome. The disease is caused by variants affecting the gene represented in this entry.  The disease is caused by variants affecting the gene represented in this entry.
== Function ==
[https://www.uniprot.org/uniprot/RPC2_HUMAN RPC2_HUMAN] Catalytic core component of RNA polymerase III (Pol III), a DNA-dependent RNA polymerase which synthesizes small non-coding RNAs using the four ribonucleoside triphosphates as substrates. Synthesizes 5S rRNA, snRNAs, tRNAs and miRNAs from at least 500 distinct genomic loci (PubMed:20413673, PubMed:33558766). Pol III-mediated transcription cycle proceeds through transcription initiation, transcription elongation and transcription termination stages. During transcription initiation, Pol III is recruited to DNA promoters type I, II or III with the help of general transcription factors and other specific initiation factors. Once the polymerase has escaped from the promoter it enters the elongation phase during which RNA is actively polymerized, based on complementarity with the template DNA strand. Transcription termination involves the release of the RNA transcript and polymerase from the DNA (PubMed:20413673, PubMed:33335104, PubMed:33558764, PubMed:33558766, PubMed:33674783, PubMed:34675218). Forms Pol III active center together with the largest subunit POLR3A/RPC1. A single-stranded DNA template strand of the promoter is positioned within the central active site cleft of Pol III. Appends one nucleotide at a time to the 3' end of the nascent RNA, with POLR3A/RPC1 contributing a Mg(2+)-coordinating DxDGD motif, and POLR3B/RPC2 participating in the coordination of a second Mg(2+) ion and providing lysine residues believed to facilitate Watson-Crick base pairing between the incoming nucleotide and template base. Typically, Mg(2+) ions direct a 5' nucleoside triphosphate to form a phosphodiester bond with the 3' hydroxyl of the preceding nucleotide of the nascent RNA, with the elimination of pyrophosphate (PubMed:19609254, PubMed:20413673, PubMed:33335104, PubMed:33558764, PubMed:33674783, PubMed:34675218). Pol III plays a key role in sensing and limiting infection by intracellular bacteria and DNA viruses. Acts as a nuclear and cytosolic DNA sensor involved in innate immune response. Can sense non-self dsDNA that serves as template for transcription into dsRNA. The non-self RNA polymerase III transcripts, such as Epstein-Barr virus-encoded RNAs (EBERs) induce type I interferon and NF-kappa-B through the RIG-I pathway.<ref>PMID:19609254</ref> <ref>PMID:19631370</ref> <ref>PMID:20413673</ref> <ref>PMID:33335104</ref> <ref>PMID:33558764</ref> <ref>PMID:33558766</ref> <ref>PMID:33674783</ref> <ref>PMID:34675218</ref> 

==See Also==
*[[RNA polymerase 3D structures|RNA polymerase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Girbig M]]
[[Category: Misiaszek AD]]
[[Category: Mueller CW]]
[[Category: Vorlaender MK]]