Structural and dynamic effects of pseudouridine modifications on noncanonical interactions in RNA

Structural consequences of pseudouridine modifications as seen in MD trajectories. (A) In addition to the signature HB1 interaction of the U-turn (left), ψ14 is able to reversibly form alternative interactions via its H1N1 imino group, which compete with, or can temporarily disrupt HB1 (right). (B) In addition to the native U13:U18 base pair, ψ13 formed a major water-bridge interaction via its H1N1 imino group. (C) The H1N1 imino group of ψ18 forms an additional H-bond with the A17 O5′ bridging oxygen atom, increasing stability of the U-turn motif and all its signature interactions.