9yf8: Difference between revisions
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==N4 Full Virion Portal== | |||
<StructureSection load='9yf8' size='340' side='right'caption='[[9yf8]], [[Resolution|resolution]] 2.90Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[9yf8]] is a 12 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=9YF8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9YF8 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]] 2.9Å</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=9yf8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9yf8 OCA], [https://pdbe.org/9yf8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9yf8 RCSB], [https://www.ebi.ac.uk/pdbsum/9yf8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9yf8 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/PORTL_BPN4 PORTL_BPN4] Forms the portal vertex of the capsid. This portal plays critical roles in head assembly, genome packaging, neck/tail attachment, and genome ejection. The portal protein multimerizes as a single ring-shaped homododecamer arranged around a central channel.<ref>PMID:18374942</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®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
[[Category: | </div> | ||
<div class="pdbe-citations 9yf8" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Escherichia phage N4]] | |||
[[Category: Large Structures]] | |||
[[Category: Bellis NF]] | |||
[[Category: Cingolani G]] | |||
