Synthesis of tRNA analogues containing a terminal ribose locked in the South conformation to study tRNA-dependent enzymes

摘要

We report here the synthetic route of two constrained dinucleotides and the determination of the sugar puckering by NMR analyses of the starting nucleosides. Enzymatic ligation to microhelix-RNAs provide access to tRNA analogues containing a 3' terminal A~(76) locked in South conformation. Biological evaluation of our tRNA analogues has been performed using amino-acyl tRNA-dependent transferase FemX_(Wv), which mediates non-ribosomal incorporation of amino acids into the bacterial cell wall. We have shown that our tRNA analogues inhibited the aminoacyl transfer reaction catalyzed by FemX_(Wv) with IC_(50s) of 10 and 8 μM. These results indicate that FemXwv displays a moderate preference for tRNAs containing a terminal A~（76） locked in the South conformation and that a South to North switch in the conformation of the terminal ribose might contribute to the release of the uncharged tRNA~（Ala） product of the aminoacyl transfer reaction catalyzed by FernX_(wv).