9bll
Cryo-EM of RBD(EG5.1)/1301B7 Fab Complex
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 PubMedSARS-CoV-2 continues to be a public health burden, driven in-part by its continued antigenic diversification and resulting emergence of new variants. By increasing herd immunity, current vaccines have improved infection outcomes for many. However, prophylactic and treatment interventions that are not compromised by viral evolution of the Spike protein are still needed. Using a differential staining strategy with a rationally designed SARS-CoV-2 Receptor Binding Domain (RBD) - ACE2 fusion protein and a native Omicron RBD protein, we developed a recombinant human monoclonal antibody (hmAb) from a convalescent individual following SARS-CoV-2 Omicron infection. The resulting hmAb, 1301B7 potently neutralized a wide range of SARS-CoV-2 variants including the original Wuhan-1, the more recent Omicron JN.1 strain, and SARS-CoV. 1301B7 contacts the ACE2 binding site of RBD exclusively through its VH1-69 heavy chain. Broad specificity is achieved through 1301B7 binding to many conserved residues of Omicron variants including Y501 and H505. Consistent with its extensive binding epitope, 1301B7 is able to potently diminish viral burden in the upper and lower respiratory tract and protect mice from challenge with Omicron XBB1.5 and Omicron JN.1 viruses. These results suggest 1301B7 has broad potential to prevent or treat clinical SARS-CoV-2 infections and to guide development of RBD-based universal SARS-CoV-2 prophylactic vaccines and therapeutic approaches. Potent neutralization by a RBD antibody with broad specificity for SARS-CoV-2 JN.1 and other variants.,Piepenbrink MS, Khalil AM, Chang A, Mostafa A, Basu M, Sarkar S, Panjwani S, Ha YH, Ma Y, Ye C, Wang Q, Green TJ, Kizziah JL, Erdmann NB, Goepfert PA, Liu L, Ho DD, Martinez-Sobrido L, Walter MR, Kobie JJ Npj Viruses. 2024;2(1):55. doi: 10.1038/s44298-024-00063-z. Epub 2024 Nov 14. PMID:39553825[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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