RlmA(II) is found only in several groups of gram positive bacteria (Steptomyces and Streptococcus). It catalyzes the formation of m1G at position 748 in the loop of helix 35 of large subunit rRNA. It confers resistance to tylosin and other mycinosylated macrolide antibiotics. In vitro it works on naked 23S rRNA. AdoMet is the donor of methyl group. RlmA(II) is the ortholog of RlmA(I) that is found only in gram negative bacteria (such as E. coli).
Methylation site was determined for E. coli rRNA.