View source for 8dm3


==Cryo-EM structure of SARS-CoV-2 Omicron BA.2 spike protein in complex with Fab 4A8==
<StructureSection load='8dm3' size='340' side='right'caption='[[8dm3]], [[Resolution|resolution]] 2.37&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8dm3]] is a 9 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome_coronavirus_2 Severe acute respiratory syndrome coronavirus 2]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8DM3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8DM3 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</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=8dm3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8dm3 OCA], [https://pdbe.org/8dm3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8dm3 RCSB], [https://www.ebi.ac.uk/pdbsum/8dm3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8dm3 ProSAT]</span></td></tr>
</table>
== Function ==
[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]
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The BA.2 sub-lineage of the Omicron (B.1.1.529) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant rapidly supplanted the original BA.1 sub-lineage in early 2022. Both lineages threatened the efficacy of vaccine-elicited antibodies and acquired increased binding to several mammalian ACE2 receptors. Cryoelectron microscopy (cryo-EM) analysis of the BA.2 spike (S) glycoprotein in complex with mouse ACE2 (mACE2) identifies BA.1- and BA.2-mutated residues Q493R, N501Y, and Y505H as complementing non-conserved residues between human and mouse ACE2, rationalizing the enhanced S protein-mACE2 interaction for Omicron variants. Cryo-EM structures of the BA.2 S-human ACE2 complex and of the extensively mutated BA.2 amino-terminal domain (NTD) reveal a dramatic reorganization of the highly antigenic N1 loop into a beta-strand, providing an explanation for decreased binding of the BA.2 S protein to antibodies isolated from BA.1-convalescent patients. Our analysis reveals structural mechanisms underlying the antigenic drift in the rapidly evolving Omicron variant landscape.

Structural analysis of receptor engagement and antigenic drift within the BA.2 spike protein.,Saville JW, Mannar D, Zhu X, Berezuk AM, Cholak S, Tuttle KS, Vahdatihassani F, Subramaniam S Cell Rep. 2023 Jan 4;42(1):111964. doi: 10.1016/j.celrep.2022.111964. PMID:36640338<ref>PMID:36640338</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8dm3" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Severe acute respiratory syndrome coronavirus 2]]
[[Category: Berezuk AM]]
[[Category: Cholak S]]
[[Category: Mannar D]]
[[Category: Saville JW]]
[[Category: Subramaniam S]]
[[Category: Tuttle KS]]
[[Category: Vahdatihassani F]]
[[Category: Zhu X]]