Native Chemical Ligation of Hydrolysis-Resistant 3′-Peptidyl–tRNA Mimics

Hydrolysis-resistant 3'-peptidyl-RNA conjugates that mimic tRNA termini represent a remarkable synthetic challenge, particularly if they contain amino acids with complex side-chain functionalities, such as arginines. Here we demonstrate a novel approach that combines solid-phase synthesis and bioconjugation to obtain these derivatives with high efficiency and purity. The key step is native chemical ligation of 3'-cysteinyl-RNA fragments to highly soluble peptide thioesters. The so-prepared 3'-peptidyl-RNA conjugates relate to resistance peptides that can render the ribosome resistant to macrolide antibiotics by a yet unknown ribosomal translation mechanism.