N²,N²-Dimethylguanosine (m 2 2 G) is a key post-transcriptional modification found in tRNAs, where two methyl groups are added to the N² position of guanosine. This modification is essential for improving tRNA structural stability and functionality, particularly at positions like G26, which are critical for ensuring the correct conformation for efficient translation. Enzymes such as Trm1 (in yeast) and TRMT1 (in humans) catalyze the formation of m²₂G using S-adenosylmethionine (SAM) as a methyl donor. This modification supports cellular functions, modulates stress responses, and ensures proper translation efficiency.