RNA recognition mechanism of eukaryote tRNA (m7G46) methyltransferase (Trm8–Trm82 complex)

Yeast tRNA (m7G46) methyltransferase contains two protein subunits (Trm8 and Trm82). To address the RNA recognition mechanism of the Trm8–Trm82 complex, we investigated methyl acceptance activities of eight truncated yeast tRNAPhe transcripts. Both the D-stem and T-stem structures were required for efficient methyl-transfer. To clarify the role of the D-stem structure, we tested four mutant transcripts, in which tertiary base pairs were disrupted. The tertiary base pairs were important but not essential for the methyl-transfer to yeast tRNAPhe transcript, suggesting that these base pairs support the induced fit of the G46 base into the catalytic pocket.