This enzyme EC:2.1.1.32 used S-AdoMet to methylate tRNA. The TRM1 gene of Saccharomyces cerevisiae is necessary for the N2,N2-dimethylguanosine modification of both mitochondrial and cytoplasmic tRNAs [1]. The enzyme is found in both eukaryotes and archaebacteria [2]

1: The tRNA(guanine-26,N2-N2) methyltransferase (Trm1) from the hyperthermophilic archaeon Pyrococcus furiosus: cloning, sequencing of the gene and its expression in Escherichia coli. Constantinesco F, Benachenhou N, Motorin Y, Grosjean H; Nucleic Acids Res 1998;26:3753-3761. PMID:9685492

2: Amino-terminal extension generated from an upstream AUG codon is not required for mitochondrial import of yeast N2,N2-dimethylguanosine- specific tRNA methyltransferase. Ellis SR, Hopper AK, Martin NC; Proc Natl Acad Sci U S A 1987;84:5172-5176. PMID:3299379