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-Structure paper
Title | Visualization of conformational changes and membrane remodeling leading to genome delivery by viral class-II fusion machinery. |
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Journal, issue, pages | Nat Commun, Vol. 13, Issue 1, Page 4772, Year 2022 |
Publish date | Aug 15, 2022 |
Authors | Vidya Mangala Prasad / Jelle S Blijleven / Jolanda M Smit / Kelly K Lee / |
PubMed Abstract | Chikungunya virus (CHIKV) is a human pathogen that delivers its genome to the host cell cytoplasm through endocytic low pH-activated membrane fusion mediated by class-II fusion proteins. Though ...Chikungunya virus (CHIKV) is a human pathogen that delivers its genome to the host cell cytoplasm through endocytic low pH-activated membrane fusion mediated by class-II fusion proteins. Though structures of prefusion, icosahedral CHIKV are available, structural characterization of virion interaction with membranes has been limited. Here, we have used cryo-electron tomography to visualize CHIKV's complete membrane fusion pathway, identifying key intermediary glycoprotein conformations coupled to membrane remodeling events. Using sub-tomogram averaging, we elucidate features of the low pH-exposed virion, nucleocapsid and full-length E1-glycoprotein's post-fusion structure. Contrary to class-I fusion systems, CHIKV achieves membrane apposition by protrusion of extended E1-glycoprotein homotrimers into the target membrane. The fusion process also features a large hemifusion diaphragm that transitions to a wide pore for intact nucleocapsid delivery. Our analyses provide comprehensive ultrastructural insights into the class-II virus fusion system function and direct mechanistic characterization of the fundamental process of protein-mediated membrane fusion. |
External links | Nat Commun / PubMed:35970990 / PubMed Central |
Methods | EM (subtomogram averaging) / EM (single particle) |
Resolution | 6.75 - 27.2 Å |
Structure data | EMDB-27248: Sub-tomogram averaged map of full-length post-fusion CHIKV E1 glycoprotein trimer EMDB-27559: Cryo-EM map of Chikungunya virus strain s27 |
Chemicals | ChemComp-BR: ChemComp-HO: ChemComp-PO4: ChemComp-HOH: |
Source |
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Keywords | VIRAL PROTEIN / envelope glycoprotein / membrane fusion / virus |