FIG 5.

RV14 5′-CL NMR/SAXS-based structure. (a) Open conformation observed in the absence of magnesium. SLB and SLD are approximately at a right angle to each other. SLC is obscured by stem A (SA) in this view. The positions of the three SLD mismatch base pairs and the SLB C-rich loop region are indicated. (b) Closed conformation observed in the presence of magnesium. SLB and SLD are parallel and in close contact, facilitated by a magnesium counter ion(s); SLC is again obscured. (c) Closed conformation from panel b, rotated 90° to show that the accessible major grooves of SLB and SLD align to create an extensive accessible major groove surface (arrow). SLB is largely obscured by SLD in this view.