View source for 7kxk


==SARS-CoV-2 spike protein in complex with Fab 15033-7, 2-"up"-1-"down" conformation==
<StructureSection load='7kxk' size='340' side='right'caption='[[7kxk]], [[Resolution|resolution]] 5.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7kxk]] 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=7KXK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7KXK 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]] 5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BMA:BETA-D-MANNOSE'>BMA</scene>, <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=7kxk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7kxk OCA], [https://pdbe.org/7kxk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7kxk RCSB], [https://www.ebi.ac.uk/pdbsum/7kxk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7kxk 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 ==
Neutralizing antibodies (nAbs) hold promise as therapeutics against COVID-19. Here, we describe protein engineering and modular design principles that have led to the development of synthetic bivalent and tetravalent nAbs against SARS-CoV-2. The best nAb targets the host receptor binding site of the viral S-protein and tetravalent versions block entry with a potency exceeding bivalent nAbs by an order of magnitude. Structural studies show that both the bivalent and tetravalent nAbs can make multivalent interactions with a single S-protein trimer, consistent with the avidity and potency of these molecules. Significantly, we show that the tetravalent nAbs show increased tolerance to potential virus escape mutants and an emerging variant of concern. Bivalent and tetravalent nAbs can be produced at large-scale and are as stable and specific as approved antibody drugs. Our results provide a general framework for enhancing antiviral therapies against COVID-19 and related viral threats, and our strategy can be applied to virtually any antibody drug.

Tetravalent SARS-CoV-2 Neutralizing Antibodies Show Enhanced Potency and Resistance to Escape Mutations.,Miersch S, Li Z, Saberianfar R, Ustav M, Brett Case J, Blazer L, Chen C, Ye W, Pavlenco A, Gorelik M, Garcia Perez J, Subramania S, Singh S, Ploder L, Ganaie S, Chen RE, Leung DW, Pandolfi PP, Novelli G, Matusali G, Colavita F, Capobianchi MR, Jain S, Gupta JB, Amarasinghe GK, Diamond MS, Rini J, Sidhu SS J Mol Biol. 2021 Sep 17;433(19):167177. doi: 10.1016/j.jmb.2021.167177. Epub 2021 , Jul 28. PMID:34329642<ref>PMID:34329642</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7kxk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Antibody 3D structures|Antibody 3D structures]]
*[[Spike protein 3D structures|Spike protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Severe acute respiratory syndrome coronavirus 2]]
[[Category: Li Z]]
[[Category: Rini J]]