Distinct Modified Nucleosides in tRNA Trp from the Hyperthermophilic Archaeon Thermococcus kodakarensis and Requirement of tRNA m 2 G10/m 2 2 G10 Methyltransferase (Archaeal Trm11) for Survival at High Temperatures

Thermococcus kodakarensis is a hyperthermophilic archaeon that can grow at 60 to 100°C. The sequence of tRNATrp from this archaeon was determined by liquid chromatography/mass spectrometry. Fifteen types of modified nucleoside were observed at 21 positions, including 5 modifications at novel positions; in addition, methylwyosine at position 37 was newly observed in an archaeal tRNATrp . The construction oftrm11 (Δtrm11 ) and other gene disruptant strains confirmed the enzymes responsible for modifications in this tRNA. The lack of 2-methylguanosine (m2 G) at position 67 in thetrm11 trm14 double disruptant strain suggested that this position is methylated by Trm14, which was previously identified as an m2 G6 methyltransferase. The Δtrm11 strain grew poorly at 95°C, indicating that archaeal Trm11 is required forT. kodakarensis survival at high temperatures.