Fig. 3
From: Crystal structure of an adenovirus virus-associated RNA
Stacked apical and tetra-stems from the PKR-inhibitory core. a Structure of the three-helix junction involving the coaxially stacked apical stem and tetrastem, and Stem 7. The junctional C93 is shown in cyan. b Secondary structures of a mutant VA-I harboring a mismatched tetrastem, a truncated apical stem (AS)-only construct, and a topologically engineered mini-VA RNA where the apical stem is fused to the tetrastem. The RNA termini are highlighted in red. c Structure of the G39–C120·C93 base triple. Note the two additional backbone hydrogen bonds from C93 to C120 and C94 connecting the tetrastem to Stem 7. d Effects of C93 substitutions and mutants in c on PKR inhibition. Individual titration curves for singly substituted mutants are colored based on the identity of the new nucleobase (A: red diamonds; C: blue circles; G: purple squares; U: green triangles). Error bars represent s.d. from three independent replicates
