Fig. 4.

Fitting the crystal structure of VP39 in complex with a single-stranded RNA hexamer into the 2′-O-MTase domain of VP3. (a) Left: The crystal structure of VP39 in complex with a single-stranded RNA hexamer (pink) is fitted into the 2′-O-MTase domain of a VP3 monomer (blue). Middle: Zoom-in view of the left view. Right: The same view as the middle except that VP39 structure is removed for clarity (only the RNA model is shown). It shows that these fragmented density features of RNA (magenta) approaching the active site of the 2′-O-MTase domain are distributed along the strand of the RNA model built based on the structure of VP39 complex. (b) Left: The structure in (a) is rotated by 210°. Middle: Zoom-in view of the left view. Right: The same view as the middle except that VP39 structure is removed for clarity (only the RNA model is shown). It shows that, after the methylation, the RNA can exit through the channel formed by monomer A (yellow) and monomer B (blue).