[1FT-3] Protein/cellular functions, Imaging (1P-49～1P-61)

[1P-58*] Interactional analysis between tRNAs and their Se-modification enzyme SelU

^○Takuya Usui¹, Hana Oe¹, Akiyoshi Nakamura², Toyoyuki Ose^1,3, Min Yao^1,3 (1.Grad. Sch. of Life. Sci., Hokkaido Univ, 2.Ins. of. Bio. pro., AIST, 3.Adv. Life. Sci., Hokkaido Univ)

tRNA is an adaptor that carries amino acids corresponding to mRNA (codon) to ribosomes for protein translation in the cell. After transcription, the maturation of tRNAs including modifications, is essential for their function. To date, about 100 types of tRNA modifications have been found. Among those modifications, only the 2-selenouridine modification has been found to use selenium atoms. In some prokaryotes, 2-selenouridine synthetase (SelU) synthesizes 5-methylaminomethyl-2-selenouridine (mnm5se2U34) at position 34 (anticodon 1) of three tRNAs (tRNA^Glu/Gln/Lys) by catalyzing both geranylation and selenation of tRNA. SelU firstly synthesizes an intermediate, 5-methylaminomethyl-2-geranilthiouridin (mnm5ges2U34) from 5-methylaminomethyl-2-thiouridine (mnm5s2U34), then forms mnm5se2U34. Because this modification changes affinities of codon-anticodon, it is conceivable to regulate translation efficiency. However, it is unclear how SelU binds to the three types of tRNAs to regulate translation efficiency. In this study, we analyzed the tRNAs which bind to SelU in vivo for understanding the regulation of translation by Se modification. We will report and discuss the detailed results in this presentation.