Figure 3.

Electrostatic free energy ΔG as a function of [Mg²⁺] for the adenine riboswitch with 50 mM K⁺, tRNA with 10 mM Na⁺, 40 bp A-RNA duplex with 10 mM Na⁺, tRNA with 32 mM Na⁺, rRNA-protein complex with 60 mM K⁺, and 40 bp B-DNA duplex with 5 mM Na⁺, from top to bottom at [Mg²⁺] = 10⁻⁶ M, respectively.