View source for 7ya1


==Cryo-EM structure of hACE2-bound SARS-CoV-2 Omicron spike protein with L371S, P373S and F375S mutations (local refinement)==
<StructureSection load='7ya1' size='340' side='right'caption='[[7ya1]], [[Resolution|resolution]] 3.11&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7ya1]] is a 2 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=7YA1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7YA1 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>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=7ya1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7ya1 OCA], [https://pdbe.org/7ya1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7ya1 RCSB], [https://www.ebi.ac.uk/pdbsum/7ya1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7ya1 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]
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== Publication Abstract from PubMed ==
Omicron SARS-CoV-2 is rapidly spreading worldwide. To delineate the impact of emerging mutations on spike's properties, we performed systematic structural analyses on apo Omicron spike and its complexes with human ACE2 or S309 neutralizing antibody (NAb) by cryo-EM. The Omicron spike preferentially adopts the one-RBD-up conformation both before and after ACE2 binding, which is in sharp contrast to the orchestrated conformational changes to create more up-RBDs upon ACE2 binding as observed in the prototype and other four variants of concern (VOCs). Furthermore, we found that S371L, S373P and S375F substitutions enhance the stability of the one-RBD-up conformation to prevent exposing more up-RBDs triggered by ACE2 binding. The increased stability of the one-RBD-up conformation restricts the accessibility of S304 NAb, which targets a cryptic epitope in the closed conformation, thus facilitating the immune evasion by Omicron. These results expand our understanding of Omicron spike's conformation, receptor binding and antibody evasion mechanism.

Omicron SARS-CoV-2 mutations stabilize spike up-RBD conformation and lead to a non-RBM-binding monoclonal antibody escape.,Zhao Z, Zhou J, Tian M, Huang M, Liu S, Xie Y, Han P, Bai C, Han P, Zheng A, Fu L, Gao Y, Peng Q, Li Y, Chai Y, Zhang Z, Zhao X, Song H, Qi J, Wang Q, Wang P, Gao GF Nat Commun. 2022 Aug 24;13(1):4958. doi: 10.1038/s41467-022-32665-7. PMID:36002453<ref>PMID:36002453</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 7ya1" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Severe acute respiratory syndrome coronavirus 2]]
[[Category: Gao GF]]
[[Category: Qi JX]]
[[Category: Xie YF]]
[[Category: Zhao ZN]]