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AM12-347 Fab in complex with HIV-1 Env 5MUT-3fill SOSIP
Structural highlights
FunctionQ2N0S6_HV1 Envelope glycoprotein gp160: Oligomerizes in the host endoplasmic reticulum into predominantly trimers. In a second time, gp160 transits in the host Golgi, where glycosylation is completed. The precursor is then proteolytically cleaved in the trans-Golgi and thereby activated by cellular furin or furin-like proteases to produce gp120 and gp41.[HAMAP-Rule:MF_04083] Surface protein gp120: Attaches the virus to the host lymphoid cell by binding to the primary receptor CD4. This interaction induces a structural rearrangement creating a high affinity binding site for a chemokine coreceptor like CXCR4 and/or CCR5. Acts as a ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which are respectively found on dendritic cells (DCs), and on endothelial cells of liver sinusoids and lymph node sinuses. These interactions allow capture of viral particles at mucosal surfaces by these cells and subsequent transmission to permissive cells. HIV subverts the migration properties of dendritic cells to gain access to CD4+ T-cells in lymph nodes. Virus transmission to permissive T-cells occurs either in trans (without DCs infection, through viral capture and transmission), or in cis (following DCs productive infection, through the usual CD4-gp120 interaction), thereby inducing a robust infection. In trans infection, bound virions remain infectious over days and it is proposed that they are not degraded, but protected in non-lysosomal acidic organelles within the DCs close to the cell membrane thus contributing to the viral infectious potential during DCs' migration from the periphery to the lymphoid tissues. On arrival at lymphoid tissues, intact virions recycle back to DCs' cell surface allowing virus transmission to CD4+ T-cells.[HAMAP-Rule:MF_04083] Transmembrane protein gp41: Acts as a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During fusion of viral and target intracellular membranes, 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. Complete fusion occurs in host cell endosomes and is dynamin-dependent, however some lipid transfer might occur at the plasma membrane. The virus undergoes clathrin-dependent internalization long before endosomal fusion, thus minimizing the surface exposure of conserved viral epitopes during fusion and reducing the efficacy of inhibitors targeting these epitopes. Membranes fusion leads to delivery of the nucleocapsid into the cytoplasm.[HAMAP-Rule:MF_04083] Publication Abstract from PubMedA major obstacle confronting HIV-1 vaccine and cure research is the lack of an outbred animal model for rapid and consistent induction of broadly neutralizing antibodies (bNAbs). We designed an epitope-focused simian-human immunodeficiency virus (SHIV.5MUT) that elicited broad and potent V3-glycan-targeted antibodies within a year of infection in 14 of 22 macaques compared with 0 of 14 control animals. SHIV.5MUT elicited bNAbs by a two-step mechanism, inducing an initial wave of V1-directed antibodies that selected for Envs with shortened, hypoglycosylated V1 loops, which in turn primed V3-glycan bNAb precursors. Rhesus bNAbs were immunogenetically and structurally diverse, closely resembling human V3-glycan bNAbs. Env-bNAb coevolution revealed a diverse repertoire of bNAb precursors and the Env variants that matured them, yielding a molecular blueprint for vaccine design. Induction of broadly neutralizing HIV antibodies by a two-step mechanism informs vaccine design.,Skelly AN, Gristick HB, Li H, Gavor E, Connell AJ, Kreider EF, Marchitto L, Hogarty MP, Newby ML, Allen JD, Liu W, West AP Jr, Ayyanathan K, Campion MS, Winters K, Gordon CG, Osbaldeston RA, Akeley MJ, Lewis E, Li Y, Singh A, Cruickshank K, Park Y, Zhao C, Li X, Amereh K, Van Itallie E, Carey JW, Albertus A, DeLaitsch AT, Keeffe JR, Lituchy MG, Walsh AA, Morris DJ, Habib R, Bibollet-Ruche F, Mishra N, Avillion G, Koranda NS, Plante SJ, Martella CL, Lora J, Wang EJD, Lewis MG, Martin MA, Nussenzweig MC, Seaman MS, Irvine DJ, Wiehe KJ, Haynes BF, Wagh K, Korber B, Andrabi R, Crispin M, Weissman D, Bjorkman PJ, Hahn BH, Shaw GM Science. 2026 May 7:eaec6396. doi: 10.1126/science.aec6396. PMID:42096521[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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