View source for 9pnr


==N4 vRNAP gp50 - Closed Complex==
<StructureSection load='9pnr' size='340' side='right'caption='[[9pnr]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9pnr]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_phage_N4 Escherichia phage N4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9PNR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9PNR 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]] 2.8&#8491;</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=9pnr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9pnr OCA], [https://pdbe.org/9pnr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9pnr RCSB], [https://www.ebi.ac.uk/pdbsum/9pnr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9pnr ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RPOLV_BPN4 RPOLV_BPN4] DNA-dependent RNA polymerase, which is injected into the host upon infection and transcribes the phage early genes from promoters that have a 5-bp stem-3 nt loop hairpin structure.<ref>PMID:18362338</ref> <ref>PMID:19061645</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Schitoviruses are widespread prokaryotic viruses that encapsidate a giant (~3,500-residue) virion-associated RNA polymerase (vRNAP). During infection, vRNAP is expelled into Gram-negative bacteria, along with two additional ejection proteins, to assemble a transient DNA-ejectosome that becomes transcriptionally active, initiating viral replication. Here, we present an integrative structural analysis of the coliphage N4 vRNAP (gp50). We find that this 383 kDa enzyme is a multi-domain, single-chain RNA polymerase, structurally distinct from both compact single-chain RNAPs and large multi-subunit holoenzymes. vRNAP is composed of loosely connected domains and exhibits an intramolecular mode of allosteric regulation through its C-terminal domain. Comparative analysis of intact and genome-released virions identified gp51, which forms an outer-membrane complex, and gp52, which assembles a periplasmic tunnel. These proteins generate heterogeneous pores that facilitate the release of vRNAP. We further uncover a signaling hub in the phage tail, composed of the receptor-binding protein, tail tube, and tail plug, that detects receptor engagement and orchestrates the release of ejection proteins. We propose that the beads-on-a-string architecture of vRNAP enables the translocation of megadalton-scale protein complexes through the ~35 A channel formed by the tail and ejection proteins. These findings establish N4 as a distinctive model for protein translocation through biological channels.

Structure of the giant RNA polymerase ejected from coliphage N4.,Bellis NF, Lokareddy RK, Pavlenok M, Horton SLC, Kizziah JL, Forti F, Schneider DA, Niederweis M, Briani F, Cingolani G Res Sq [Preprint]. 2025 Oct 21:rs.3.rs-7746245. doi: 10.21203/rs.3.rs-7746245/v1. PMID:41282253<ref>PMID:41282253</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9pnr" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia phage N4]]
[[Category: Large Structures]]
[[Category: Bellis NF]]
[[Category: Cingolani G]]
[[Category: Lokareddy RK]]