Extended Data Fig. 3: N³²⁴ is present in various class I tRNAs.

(a) RNA-MS of RNase T₁ digests of the isolated S. tokodaii tRNAs. XICs show negative ions of RNA fragments derived from V-loop containing N³²⁴ (red line) or U (black line) at position 47. Sequence and m/z value of each fragment are provided in Supplementary Table 2. Modification frequency of N³²⁴ indicated in each tRNA was calculated from relative peak intensities of the modified and unmodified fragments. Unassigned fragments are indicated by asterisks. (b) CID spectrum of the RNA fragments detected in (a). The negatively-charged ion of each fragment was used as a precursor ion for CID analysis. The product ions in the CID spectrum are assigned on the sequences. N³²⁴ is shown in red. (c) N³²⁴ is introduced in precursor tRNAs. RNA-MS of RNase T₁ digests of the precursor tRNAs for Ile2 and Phe isolated from S. tokodaii (Extended Data Fig. 1). XICs show negative ions of the RNA fragments derived from V-loop containing N³²⁴ (red line) or U (black line) at position 47. Modification frequency of N³²⁴ indicated in each tRNA was calculated from relative peak intensities of the modified and unmodified fragments.