5L4O

Structure of an E.coli initiator tRNAfMet A1-U72 variant

5L4O の概要

• エントリーDOI: 10.2210/pdb5l4o/pdb
• 分子名称: tRNA (76-MER), SODIUM ION (3 entities in total)
• 機能のキーワード: trna-translation initiation, translation
• 由来する生物種: Escherichia coli
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 24856.89

構造登録者

Monestier, A.,Schmitt, E.,Mechulam, Y. (登録日: 2016-05-26, 公開日: 2017-03-01, 最終更新日: 2024-01-10)

主引用文献

Monestier, A.,Aleksandrov, A.,Coureux, P.D.,Panvert, M.,Mechulam, Y.,Schmitt, E.
The structure of an E. coli tRNAf(Met) A1-U72 variant shows an unusual conformation of the A1-U72 base pair.
RNA, 23:673-682, 2017

PubMed Abstract: Translation initiation in eukaryotes and archaea involves a methionylated initiator tRNA delivered to the ribosome in a ternary complex with e/aIF2 and GTP. Eukaryotic and archaeal initiator tRNAs contain a highly conserved A-U base pair at the top of the acceptor stem. The importance of this base pair to discriminate initiator tRNAs from elongator tRNAs has been established previously using genetics and biochemistry. However, no structural data illustrating how the A-U base pair participates in the accurate selection of the initiator tRNAs by the translation initiation systems are available. Here, we describe the crystal structure of a mutant initiator tRNAA-U, aminoacylated with methionine, in which the C:A mismatch at the end of the tRNA acceptor stem has been changed to an A-U base pair. Sequence alignments show that the mutant tRNA is a good mimic of archaeal initiator tRNAs. The crystal structure, determined at 2.8 Å resolution, shows that the A-U pair adopts an unusual arrangement. A is in a conformation and forms a single H-bond interaction with U This interaction requires protonation of the N1 atom of A Moreover, the 5' phosphoryl group folds back into the major groove of the acceptor stem and interacts with the N7 atom of G A possible role of this unusual geometry of the A-U pair in the recognition of the initiator tRNA by its partners during eukaryotic and archaeal translation initiation is discussed.

PubMed: 28143889
DOI: 10.1261/rna.057877.116

実験手法

X-RAY DIFFRACTION (2.799 Å)