tRNA Methyltransferase 1 Homolog (TRMT1)

tRNA methyltransferase-1 catalyzes dimethylation at the exocyclic 2-amino group of guanine 26 in tRNAs using S-adenosyl-L-methionine as substrate.

The human cDNA encodes a deduced 659-amino acid protein that is 26% and 31% identical to the yeast and C. elegans homologs, respectively. When the human protein was expressed in E. coli, which lacks tRNA(m2,2G)dimethyltransferase activity, it was able to catalyze the formation of dimethylguanosine. Further, TRM1 specifically targeted the G26 position of human tRNA(Tyr). Mutation analysis showed that alterations in the conserved regions of the protein completely abrogated enzyme activity.