Figure 1.

Selected snapshots from the sodium-containing ssRNA simulations: (a) two bound Na⁺ ions directly coordinated at phosphate groups P1 and P2 in a CC ssRNA fragment; (b) two solvated Na⁺ ions interacting through their inner hydration shells with phosphate groups P1 and P2 in a CC ssRNA fragment; (c) two bound Na⁺ ions directly coordinated at O5 from the guanine base or O6 from the hydroxyl group attached to the pentose ring in the 2′ position of guanosine in a GC ssRNA fragment.