The Escherichia coli RlmN methyltransferase is a dual-specificity enzyme that modifies both rRNA and tRNA and controls translational accuracy

RlmN is the first example of a methyltransferase working on both rRNA and tRNA. The figure shows the distribution of the Escherichia coli modified nucleotides by RNA type. The position of each modification (in parentheses) and the enzyme(s) responsible for its synthesis are indicated. Only two enzymes, RluA and the herein studied RlmN, have dual substrate specificity, recognizing both rRNA and tRNA. (*) Modifications of 16S rRNA; (unk) unknown enzyme; (^‡) modification h⁵C2501 is partial and dependent on the growth phase (Andersen et al. 2004; Havelund et al. 2011).