%0 Journal Article %A Bleykasten, Claudine %A Gilmer, D. %A Guilley, H. %A Richards, K. E. %A Jonard, G. %T Beet necrotic yellow vein virus 42 kDa triple gene block protein binds nucleic acid in vitro %D 1996 %J Journal of General Virology, %V 77 %N 5 %P 889-897 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-77-5-889 %I Microbiology Society, %X The triple gene block (TGB) of beet necrotic yellow vein virus RNA 2 is required for cell-to-cell movement of the virus RNA. The protein P42 encoded by the 5′-proximal gene of the TGB has consensus sequence motifs characteristic of an ATP/GTP-dependent helicase. P42 was over-expressed in Escherichia coli and shown to bind both single- and double-stranded RNA and DNA by Northwestern blotting. Site-directed mutagenesis located the nucleic acid-binding domain to the N-terminal 24 amino acids of the protein and a point mutation or deletions in the region of P42 containing the helicase consensus sequences did not affect nucleic acid-binding activity of the immobilized protein. Electrophoretic mobility-shift assays revealed that P42 also binds nucleic acids in solution and that deletion of the N-terminal region inhibits this binding. Mutations in both the N-terminal nucleic acid-binding domain and the helicase domain blocked infection of leaves, indicating that both regions of P42 are important for its activity in vivo. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-77-5-889