Synthesis of stable aminoacyl-tRNA analogs

Aminoacyl-tRNAs have important roles in a variety of biological processes. Here, we describe the synthesis of stable aminoacyl-tRNA analogs containing 1,4-substituted 1,2,3-triazole rings. The procedure involves (i) copper-catalyzed cycloadditions of 3'-or 2'-azido-adenosine and alkynes, (ii) coupling between the resulting triazole-deoxyadenosine derivatives and a deoxycytidine phosphoramidite, and (iii) the enzymatic ligation of the 2'- or 3'-triazole-dinucleotides with a 22-nt RNA microhelix that mimics the acceptor arm of tRNA. Each nucleoside and nucleotide intermediate was characterized by MS spectrometry and (1)H, (31)P, and (13)C NMR spectroscopy, and the tRNA-analogs were assayed for inhibition of FemXWv, an alanyl-transferase essential for the formation of the peptidoglycan network of Gram-positive bacterial pathogens. The low IC(50) values obtained (2 to 4 µM) indicate that the five-membered triazole rings acted as an isosteres of esters and can be used for the design of stable aminoacyl-tRNA analogs.