262 Chapter 7
Figure 7.11 Metal ions in RNA tertiary structure. Direct interactions between RNA and divalent cations can take
two forms: (a) Outer-sphere and (b) Inner-sphere
Figure 7.12 A-platform motifs in RNA structure. (a) Secondary structural morphology of an A-platform. (b) Tertiary
structure of the platform. The specifically bound Kion is shown as a gold sphere
(Reprinted from Ref. 18. © (1998), with permission from Macmillan Publications Ltd)