The naturally occurring N6-threonyl adenine in anticodon loop of Schizosaccharomyces pombe tRNAi causes formation of a unique U-turn motif.
Modified nucleosides play an important role in structure and function of tRNA. We have determined the solution structure of the anticodon stem-loop (ASL) of initiator tRNA of Schizosaccharomyces pombe. The incorporation of N6-threonylcarbamoyladenosine at the position 3' to the anticodon triplet (t6A37) results in the formation of a U-turn motif and enhances stacking interactions within the loop and stem regions (i.e. between A35 and t6A37) by bulging out U36. This conformation was not observed in a crystal structure of tRNAi including the same modification in its anticodon loop, nor in the solution structure of the unmodified ASL. A t6A modification also occurs in the well studied anti-stem-loop of lys-tRNA(UUU). A comparison of this stem-loop with our structure demonstrates different effects of the modification depending on the loop sequence.
Lescrinier
Eveline
E
Laboratory of Medicinal Chemistry, Rega Institute for Medical Research BioMacs, K.U.Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium.
Nauwelaerts
Koen
K
Zanier
Katia
K
Poesen
Koen
K
Sattler
Michael
M
Herdewijn
Piet
P
D000225:Adenine / Q000031:analogs & derivatives* / Q000737:chemistry; D000926:Anticodon / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D012331:RNA, Fungal / Q000737:chemistry; D012357:RNA, Transfer, Lys / Q000737:chemistry; D012358:RNA, Transfer, Met / Q000737:chemistry*; D012568:Schizosaccharomyces / Q000235:genetics*; D012996:Solutions; D013912:Threonine / Q000031:analogs & derivatives* / Q000737:chemistry
D000926:Anticodon; D012331:RNA, Fungal; D012357:RNA, Transfer, Lys; D012358:RNA, Transfer, Met; D012996:Solutions; D013912:Threonine; C003246:N-(purin-6-ylcarbamoyl)threonine; D000225:Adenine