Genetic analysis of heptad-repeat regions in the G2 fusion subunit of the Junin arenavirus envelope glycoprotein
- Montana Biotechnology Center, University of Montana, Science Complex Room 221, Missoula, MT 59812 (United States)
- Instituto de Bioquimica y Biologia Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata (Argentina) and Departmento de Ciencia y Tecnologia, Universidad Nacional de Quilmes, Bernal (Argentina)
The G2 fusion subunit of the Junin virus envelope glycoprotein GP-C contains two hydrophobic heptad-repeat regions that are postulated to form a six-helix bundle structure required for the membrane fusion activity of Class I viral fusion proteins. We have investigated the role of these heptad-repeat regions and, specifically, the importance of the putative interhelical a and d position sidechains by using alanine-scanning mutagenesis. All the mutant glycoproteins were expressed and transported to the cell surface. Proteolytic maturation at the subtilisin kexin isozyme-1/site-1-protease (SKI-1/S1P) cleavage site was observed in all but two of the mutants. Among the adequately cleaved mutant glycoproteins, four positions in the N-terminal region (I333, L336, L347 and L350) and two positions in the C-terminal region (R392 and W395) were shown to be important determinants of cell-cell fusion. Taken together, our results indicate that {alpha}-helical coiled-coil structures are likely critical in promoting arenavirus membrane fusion. These findings support the inclusion of the arenavirus GP-C among the Class I viral fusion proteins and suggest pharmacologic and immunologic strategies for targeting arenavirus infection and hemorrhagic fever.
- OSTI ID:
- 20779443
- Journal Information:
- Virology, Journal Name: Virology Journal Issue: 2 Vol. 343; ISSN VIRLAX; ISSN 0042-6822
- Country of Publication:
- United States
- Language:
- English
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