View source for 7xxl


==RBD in complex with Fab14==
<StructureSection load='7xxl' size='340' side='right'caption='[[7xxl]], [[Resolution|resolution]] 7.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7xxl]] is a 3 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=7XXL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7XXL 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]] 7.3&#8491;</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=7xxl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7xxl OCA], [https://pdbe.org/7xxl PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7xxl RCSB], [https://www.ebi.ac.uk/pdbsum/7xxl PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7xxl 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 ==
One major limitation of neutralizing antibody-based COVID-19 therapy is the requirement of costly cocktails to reduce emergence of antibody resistance. Here we engineer two bispecific antibodies (bsAbs) using distinct designs and compared them with parental antibodies and their cocktail. Single molecules of both bsAbs block the two epitopes targeted by parental antibodies on the receptor-binding domain (RBD). However, bsAb with the IgG-(scFv)(2) design (14-H-06) but not the CrossMAb design (14-crs-06) shows increased antigen-binding and virus-neutralizing activities against multiple SARS-CoV-2 variants as well as increased breadth of neutralizing activity compared to the cocktail. X-ray crystallography and cryo-EM reveal distinct binding models for individual cocktail antibodies, and computational simulations suggest higher inter-spike crosslinking potentials by 14-H-06 than 14-crs-06. In mouse models of infections by SARS-CoV-2 and multiple variants, 14-H-06 exhibits higher or equivalent therapeutic efficacy than the cocktail. Rationally engineered bsAbs represent a cost-effective alternative to antibody cocktails and a promising strategy to improve potency and breadth.

Engineering SARS-CoV-2 specific cocktail antibodies into a bispecific format improves neutralizing potency and breadth.,Ku Z, Xie X, Lin J, Gao P, Wu B, El Sahili A, Su H, Liu Y, Ye X, Tan EY, Li X, Fan X, Goh BC, Xiong W, Boyd H, Muruato AE, Deng H, Xia H, Zou J, Kalveram BK, Menachery VD, Zhang N, Lescar J, Shi PY, An Z Nat Commun. 2022 Sep 22;13(1):5552. doi: 10.1038/s41467-022-33284-y. PMID:36138032<ref>PMID:36138032</ref>

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

==See Also==
*[[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: Lescar J]]
[[Category: Lin JQ]]
[[Category: Tan YJE]]
[[Category: Wu B]]