RNA oligomers at atomic resolution containing 1-methylpseudouridine, an essential building block of mRNA vaccines.

All widely used mRNA vaccines against COVID-19 contain in their sequence 1-methylpseudouridine (m1Ψ) instead of uridine. In this publication, we report two high resolution crystal structures (at up to 1.01 and 1.32 Å, respectively) of one such double-stranded 12-mer RNA sequence crystallized in two crystal forms. The structures are compared with similar structures which do not contain this modification. Additionally, the X-ray structure of 1-methyl-pseudouridine itself was determined.