Fig. 6: RNA chaperone activity of σNS.
From: Structure of orthoreovirus RNA chaperone σNS, a component of viral replication factories
a Electrostatic representation of a σNS filament with red indicating negatively charged residues and blue indicating positively charged residues. The exterior of the filament is negatively charged. b Cutaway view of the filament. The interior of the filament is positively charged. c A single dimer is demarcated in a black-dotted frame with its relative position within the filament. d A 90-degree rotation around the z axis from the previous position shows a side view of the dimer. A docked RNA molecule is colored in yellow. e A 90-degree rotation around the z axis from the previous position shows the positively charged pocket of σNS that binds to a docked RNA molecule colored in yellow. The black-dotted frame depicts the position of the dimer within the filament. f Schematic representation of the RNA helix substrate containing overhangs at 3′ and 5′ ends. g Schematic representation of the stem-loop structures of the complementary 42-nucleotide RNA strands. The asterisk indicates the HEX-labeled strand in f and g. h RNA helix-destabilizing activity of WT σNS. Increasing concentrations of WT σNS yield more ssRNA products. MBP and norovirus (NV) p41 were used as negative and positive controls, respectively. i Helix-destabilizing activity of σNS-R6A. j RNA-annealing activity of WT σNS. Increasing formation of dsRNA with increasing σNS concentration. Boiling followed by cooling to room temperature of the two ssRNA strands was used as a control. k, l Effects of bile acid derivatives on the RNA helix-destabilizing (k) and RNA strand-annealing activity (l) of σNS. TASAH, taurocholic acid sodium salt hydrate. SGAH, sodium glycocholate hydrate. CHAPS, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate. CHAPSO, 3-[(3-cholamidopropyl)dimethylammonio]−2-hydroxy-1-propanesulfonate. m RNA-helix destabilizing activity of σNS-ΔN17. Increasing concentrations of σNS-ΔN17 does not yield significant ssRNA products. All the experiments for 6h-m are done three times independently. Source data are provided as a Source Data file.
