Download MendeleyVisualization of conformational changes and membrane remodeling leading to genome delivery by viral class-II fusion machinery.
Mangala Prasad, V., Blijleven, J.S., Smit, J.M., Lee, K.K.(2022) Nat Commun 13: 4772-4772
- PubMed: 35970990
- DOI: https://doi.org/10.1038/s41467-022-32431-9
- Primary Citation of Related Structures:
8D87 - 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 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.
Organizational Affiliation:
Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA.
