Pseudouridine and N1-Methylpseudouridine Display pH-Independent Reaction Rates with Bisulfite Yielding Ribose Adducts

In RNA, pseudouridine (Psi) and 5-methylcytidine (m(5)C) are located by their differential reactions with NaHSO3 at pH 5. The pyrimidines were allowed to react with NaHSO3, NaN3, NaCN, or NaSCN at pH 5 to find that NaHSO3 was unique in achieving quantitative yields. Pseudouridine reaction selectivity with NaHSO3 was found at pH 7 supported by the reaction rate constants. The Psi derivative N1-methylpseudouridine found in mRNA vaccines reacts similarly with bisulfite to yield ribose adducts.

Automated summary

The differential reactions of pseudouridine (Psi) and 5-methylcytidine (m(5)C) with NaHSO3 at pH 5 were used to locate their positions in RNA. The study found that NaHSO3 was unique in achieving quantitative yields compared to other reagents. The reaction selectivity of pseudouridine with NaHSO3 was supported by the reaction rate constants at pH 7. Additionally, the Psi derivative N1-methylpseudouridine in mRNA vaccines formed ribose adducts through a similar reaction with bisulfite.