View source for 8r87


==Cryo-EM structure of the Sars-Cov2 S trimer without RBDs==
<StructureSection load='8r87' size='340' side='right'caption='[[8r87]], [[Resolution|resolution]] 3.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8r87]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_virus_T4 Escherichia virus T4] and [https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome_coronavirus Severe acute respiratory syndrome coronavirus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8R87 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8R87 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&#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=8r87 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8r87 OCA], [https://pdbe.org/8r87 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8r87 RCSB], [https://www.ebi.ac.uk/pdbsum/8r87 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8r87 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/WAC_BPT4 WAC_BPT4] Chaperone responsible for attachment of long tail fibers to virus particle. Forms the fibrous structure on the neck of the virion called whiskers. During phage assembly, 6 fibritin molecules attach to each virion neck through their N-terminal domains, to form a collar with six fibers ('whiskers').[https://www.uniprot.org/uniprot/SPIKE_SARS2 SPIKE_SARS2] attaches the virion to the cell membrane by interacting with host receptor, initiating the infection (By similarity). Binding to human ACE2 receptor and internalization of the virus into the endosomes of the host cell induces conformational changes in the Spike glycoprotein (PubMed:32142651, PubMed:32075877, PubMed:32155444). Uses also human TMPRSS2 for priming in human lung cells which is an essential step for viral entry (PubMed:32142651). Proteolysis by cathepsin CTSL may unmask the fusion peptide of S2 and activate membranes fusion within endosomes.[HAMAP-Rule:MF_04099]<ref>PMID:32075877</ref> <ref>PMID:32142651</ref> <ref>PMID:32155444</ref>   mediates fusion of the virion and cellular membranes by acting as a class I viral fusion protein. Under the current model, the protein has at least three conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During viral and target cell membrane fusion, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes.[HAMAP-Rule:MF_04099]  Acts as a viral fusion peptide which is unmasked following S2 cleavage occurring upon virus endocytosis.[HAMAP-Rule:MF_04099]
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia virus T4]]
[[Category: Large Structures]]
[[Category: Severe acute respiratory syndrome coronavirus]]
[[Category: Effantin G]]