Unusual Base Pair between Two 2-Thiouridines and Its Implication for Nonenzymatic RNA Copying.

ABSTRACT: 2-Thiouridine (s²U) is a nucleobase modification that confers enhanced efficiency and fidelity both on modern tRNA codon translation and on nonenzymatic and ribozyme-catalyzed RNA copying. We have discovered an unusual base pair between two 2-thiouridines that stabilizes an RNA duplex to a degree that is comparable to that of a native A:U base pair. High-resolution crystal structures indicate similar base-pairing geometry and stacking interactions in duplexes containing s²U:s²U compared to those with U:U pairs. Notably, the C═O···H-N hydrogen bond in the U:U pair is replaced with a C═S···H-N hydrogen bond in the s²U:s²U base pair. The thermodynamic stability of the s²U:s²U base pair suggested that this self-pairin

SUBMITTER: Ding D 

PROVIDER: S-EPMC10870715 | biostudies-literature | 2024 Feb

REPOSITORIES: biostudies-literature