8iv8
From Proteopedia
Cryo-EM structure of SARS-CoV-2 spike protein in complex with double nAbs 3E2 and 1C4 (local refinement)
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 PubMedContinual evolution of the SARS-CoV-2 virus has allowed for its gradual evasion of neutralizing antibodies (nAbs) produced in response to natural infection or vaccination. The rapid nature of these changes has incited a need for the development of superior broad nAbs and/or the rational design of an antibody cocktail that can protect against the mutated virus strain. Here, we report two ACE2 competing nAbs-8H12 and 3E2-with synergistic neutralization but evaded by some Omicron subvariants. Cryo-EM reveals the two nAbs synergistic neutralizing virus through a rigorous pairing permitted by rearrangement of the 472-489 loop in the RBD to avoid steric clashing. Bispecific antibodies based on these two nAbs tremendously extend the neutralizing breadth and restore neutralization against recent variants including currently dominant XBB.1.5. Together, these findings expand our understanding of the potential strategies for the neutralization of SARS-CoV-2 variants toward the design of broad-acting antibody therapeutics and vaccines. Two antibodies show broad, synergistic neutralization against SARS-CoV-2 variants by inducing conformational change within the RBD.,Sun H, Deng T, Zhang Y, Lin Y, Jiang Y, Jiang Y, Huang Y, Song S, Cui L, Li T, Xiong H, Lan M, Liu L, Li Y, Fang Q, Yu K, Jiang W, Zhou L, Que Y, Zhang T, Yuan Q, Cheng T, Zhang Z, Yu H, Zhang J, Luo W, Li S, Zheng Q, Gu Y, Xia N Protein Cell. 2023 Jul 20:pwad040. doi: 10.1093/procel/pwad040. PMID:37470320[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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