Fig. 5: A structure of translocation intermediate exhibiting critical movement of the template RNA in an RdRP bearing mutations in the motif G hurdle residues.
a Stereo-pair images of the intermediate structure S6M with a composite SA omit electron density map (contoured at 1.2 σ) overlaid. b RNA-only comparison of this translocation intermediate (color) and the pre-translocation reference state (dark gray, PDB entry 3OL9). c Schematic illustration of the RNA movement suggested by the intermediate structure. Labeling, symbols, and coloring scheme are the same as in Fig. 2. For the S6M structure, motif G hurdle residues and motif F I176 moved with the template strand accordingly, while the electrostatic interactions between -1/-2 template phosphates and K127 and R188 were lost and the unusual -2 template backbone conformation reset to normal. d A structural comparison of pre-translocation (S5), early (S6B), and late (S6M) translocation intermediates states highlighting the coordinative conformational changes of the template strand and key residues in motifs F and G. The athlete-hurdle and ratcheting wheel cartoons are provided for better illustration of critical role of the hurdle residues 114–115. Labeling, symbols, and coloring scheme are the same as in Fig. 2 with motif G in pink.
