METTL1 is recognized as tRNA(guanine-N(7)-)-methyltransferase that is a part of the methyltransferase superfamily. METTL1 displays high sequence similarity to yeast ORF YDL201w and can be inactivated by phosphorylation. METTL1 protein has a conserved S-adenosylmethionine-binding motif and ccatalyzes the formation of N(7)-methylguanine at position 46(m7G46) in tRNA.