Figure 1 - full size

 

Figure 1.
Figure 1: Overall structure and long-range tertiary interactions of the lysine-bound T. maritima riboswitch. a, Schematic of the riboswitch fold observed in the crystal structure of the complex. The bound lysine is in red. The RNA domains are depicted in colours used for subsequent figures. Base-specific tertiary contacts and long-range stacking interactions are shown as thin green and thick blue dashed lines, respectively. Nucleotides invariant in known lysine riboswitches are boxed. b, c, Overall lysine riboswitch structure in a ribbon representation showing front (b) and rotated by 60° (c) views. d, The L2–L3 kissing loop interaction is formed by six base pairs, supplemented by interstrand stacking interactions between A42 and C95, G43 and U94, and G44 and G101. Hydrogen bonds between interstrand base pairs and orthogonally aligned G43 and U94 bases are depicted by dashed lines. e, The L4-loop–P2-helix interaction formed by an insertion of the A126–A127–A129 stack of L4 into the RNA groove of P2 distorted by non-canonical base pairs.

The above figure is reprinted by permission from Macmillan Publishers Ltd: Nature (2008, 455, 1263-1267) copyright 2008.