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

Abstract

Thermococcus kodakarensis is a hyperthermophilic archaeon that can grow at 60 to 100°C. The sequence of tRNA Trp 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 tRNA Trp . The construction of trm11 (Δ trm11 ) and other gene disruptant strains confirmed the enzymes responsible for modifications in this tRNA. The lack of 2-methylguanosine (m 2 G) at position 67 in the trm11 trm14 double disruptant strain suggested that this position is methylated by Trm14, which was previously identified as an m 2 G6 methyltransferase. The Δ trm11 strain grew poorly at 95°C, indicating that archaeal Trm11 is required for T. kodakarensis survival at high temperatures.