A Universal Support for the Solid‐Phase Synthesis of Peptidyl‐tRNA Mimics

Abstract

Hydrolysis‐resistant RNA‐peptide conjugates that mimic peptidyl‐tRNAs are often required for structural and functional studies of protein synthesis at the ribosome. These conjugates can be synthesized by solid‐phase chemical synthesis, which allows maximum flexibility in both the peptide and RNA sequence. The commonly used strategy is based on (3’‐N‐aminoacyl)‐3’‐amino‐3’‐deoxyadenosine solid supports, which already contain the first C‐terminal amino acid of the target peptidyl chain. This is a limitation in the sense that different individual supports must be synthesized for different C‐terminal amino acids. In this study, we demonstrate a solution to this problem by introducing a novel universal support. The key is a free ribose 3’‐NH2 group that can be coupled to any amino acid. This is made possible by a photocleavable ether moiety that links the ribose 2’‐O to the support, thus avoiding the typical O‐to‐N migration that occurs when using 2’‐O‐acyl linked solid supports. Once assembled, the conjugate is readily cleaved by UV irradiation. The structural integrity of the obtained peptidyl‐RNA conjugates was verified by mass spectrometry analysis. In conclusion, the new photocleavable solid support makes the synthesis of 3’‐peptidyl tRNA mimics of different peptidyl chains significantly more efficient compared to the commonly used approaches.