β-Pseudouridine also known as 5-ribosyluracil, is anisomerof thenucleosideuridinein which theuracilis attached via a carbon-carbon instead of a nitrogen-carbonglycosidic bond. Pseudouridine is a ubiquitous yet enigmatic constituent of structural RNAs (transfer,ribosomal,small nuclear(snRNA) andsmall nucleolar)