8aaa | pdb_00008aaa
Crystal structure of SARS-CoV-2 S RBD in complex with a stapled peptide
Structural highlights
FunctionSPIKE_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][1] [2] [3] 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] Publication Abstract from PubMedCOVID-19 has stimulated the rapid development of new antibody and small molecule therapeutics to inhibit SARS-CoV-2 infection. Here we describe a third antiviral modality that combines the drug-like advantages of both. Bicycles are entropically constrained peptides stabilized by a central chemical scaffold into a bi-cyclic structure. Rapid screening of diverse bacteriophage libraries against SARS-CoV-2 Spike yielded unique Bicycle binders across the entire protein. Exploiting Bicycles' inherent chemical combinability, we converted early micromolar hits into nanomolar viral inhibitors through simple multimerization. We also show how combining Bicycles against different epitopes into a single biparatopic agent allows Spike from diverse variants of concern (VoC) to be targeted (Alpha, Beta, Delta and Omicron). Finally, we demonstrate in both male hACE2-transgenic mice and Syrian golden hamsters that both multimerized and biparatopic Bicycles reduce viraemia and prevent host inflammation. These results introduce Bicycles as a potential antiviral modality to tackle new and rapidly evolving viruses. Multivalent bicyclic peptides are an effective antiviral modality that can potently inhibit SARS-CoV-2.,Gaynor KU, Vaysburd M, Harman MAJ, Albecka A, Jeffrey P, Beswick P, Papa G, Chen L, Mallery D, McGuinness B, Van Rietschoten K, Stanway S, Brear P, Lulla A, Ciazynska K, Chang VT, Sharp J, Neary M, Box H, Herriott J, Kijak E, Tatham L, Bentley EG, Sharma P, Kirby A, Han X, Stewart JP, Owen A, Briggs JAG, Hyvonen M, Skynner MJ, James LC Nat Commun. 2023 Jun 16;14(1):3583. doi: 10.1038/s41467-023-39158-1. PMID:37328472[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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