RNA helicases have not been identified among negative sense RNA viruses. In this study, it is shown that Nonstructural protein (NSs) of Groundnut bud necrosis virus (GBNV) acts as a Mg(2+) - and ATP-dependent bipolar RNA helicase. Biophysical and biochemical analysis of the deletion mutants (NΔ124 NSs, CΔ80 NSs) revealed that both the N- and C-terminal residues are required for substrate binding, oligomerization and helicase activity, but are dispensable for ATPase activity. Interestingly, NSs could enhance the translation of RNA (~ 10-fold) independent of its helicase activity. This is the first report of a RNA helicase from negative strand RNA viruses.
Keywords: Groundnut bud necrosis virus; bipolar RNA helicase; nonstructural protein; translation enhancer.
© 2016 Federation of European Biochemical Societies.