View source for 6tu5


==Influenza A/H7N9 polymerase core (apo)==
<StructureSection load='6tu5' size='340' side='right'caption='[[6tu5]], [[Resolution|resolution]] 3.33&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6tu5]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Influenza_A_virus_(A/Zhejiang/DTID-ZJU01/2013(H7N9)) Influenza A virus (A/Zhejiang/DTID-ZJU01/2013(H7N9))]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6TU5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6TU5 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]] 3.325&#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></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=6tu5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6tu5 OCA], [https://pdbe.org/6tu5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6tu5 RCSB], [https://www.ebi.ac.uk/pdbsum/6tu5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6tu5 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/M9TI86_9INFA M9TI86_9INFA] Plays an essential role in viral RNA transcription and replication by forming the heterotrimeric polymerase complex together with PB1 and PB2 subunits. The complex transcribes viral mRNAs by using a unique mechanism called cap-snatching. It consists in the hijacking and cleavage of host capped pre-mRNAs. These short capped RNAs are then used as primers for viral mRNAs. The PB2 subunit is responsible for the binding of the 5' cap of cellular pre-mRNAs which are subsequently cleaved after 10-13 nucleotides by the PA subunit that carries the endonuclease activity.[HAMAP-Rule:MF_04063][SAAS:SAAS00956500]
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== Publication Abstract from PubMed ==
Influenza polymerase uses unique mechanisms to synthesize capped and polyadenylated mRNAs from the genomic viral RNA (vRNA) template, which is packaged inside ribonucleoprotein particles (vRNPs). Here, we visualize by cryoelectron microscopy the conformational dynamics of the polymerase during the complete transcription cycle from pre-initiation to termination, focusing on the template trajectory. After exiting the active site cavity, the template 3' extremity rebinds into a specific site on the polymerase surface. Here, it remains sequestered during all subsequent transcription steps, forcing the template to loop out as it further translocates. At termination, the strained connection between the bound template 5' end and the active site results in polyadenylation by stuttering at uridine 17. Upon product dissociation, further conformational changes release the trapped template, allowing recycling back into the pre-initiation state. Influenza polymerase thus performs transcription while tightly binding to and protecting both template ends, allowing efficient production of multiple mRNAs from a single vRNP.

A Structure-Based Model for the Complete Transcription Cycle of Influenza Polymerase.,Wandzik JM, Kouba T, Karuppasamy M, Pflug A, Drncova P, Provaznik J, Azevedo N, Cusack S Cell. 2020 Apr 16. pii: S0092-8674(20)30389-5. doi: 10.1016/j.cell.2020.03.061. PMID:32304664<ref>PMID:32304664</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 6tu5" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Cusack S]]
[[Category: Pflug A]]