Fig. 2.

Mutation fractions of two tRNA sites. Heatmaps of mutation fractions for positions 22 and 8 (using standard, canonical tRNA nomenclature) are shown. tRNAs with different anticodons are grouped by their sequences at the respective position of modification (in parenthesis) and in alphabetical orders. Only E. coli and B. subtilis tRNA modifications have been mapped previously by 2D-TLC and LC/MS, but the mapping was not done for every tRNA species¹². Every E. coli and B. subtilis tRNA species with mutation fraction at10-times above background is marked with a circle on the right with the following designations: Purples correspond to those known to be present and also identified by sequencing here; blacks correspond to those supposed to be absent but identified by sequencing; greens correspond to those not mapped previously but identified by sequencing; oranges correspond to those known to be present but were not found by sequencing. a m¹A22; R corresponds to A or G. b s⁴U8