InterPro domain: IPR007356

In transfer RNA many different modified nucleosides are found, especially in the anticodon region.tRNA (guanine-N1-)-methyltransferase 2.1.1.31 is one of several nucleases operating together with the tRNA-modifying enzymes before the formation of the mature tRNA. It catalyses the reaction: S-adenosyl-L-methionine + tRNA -> S-adenosyl-L-homocysteine + tRNA containing N1-methylguanine methylating guanosine(G) to N1-methylguanine (1-methylguanosine (m1G)) at position 37 of tRNAs that read CUN (leucine), CCN(proline), and CGG (arginine) codons. The presence of m1G improves the cellular growth rate and the polypeptide steptime and also prevents the tRNA from shifting the reading frame [ 1 ].

The mechanism of the trmD3-induced frameshift involving mutant tRNA(Pro) and tRNA(Leu) species has been investigated [ 2 ]. It has been suggested that the conformation of the anticodon loop may be a major determining element for the formation of m1G37 in vivo [ 3 ].

1. Role of tRNA modification in translational fidelity. Biochim. Biophys. Acta 1050, 263-6
2. Deficiency of 1-methylguanosine in tRNA from Salmonella typhimurium induces frameshifting by quadruplet translocation. J. Mol. Biol. 232, 756-65
3. Structural requirements for the formation of 1-methylguanosine in vivo in tRNA(Pro)GGG of Salmonella typhimurium. J. Mol. Biol. 266, 283-96