Exploring the impact of the side-chain length on peptide/RNA binding eventsElectronic supplementary information (ESI) available: Chemistry: abbreviations, materials and equipment, synthetic procedures for new compounds and their characterization (1H and 13C NMR, HPLC and MS or HRMS). Six figures. See DOI: 10.1039/c7cp03726k

• Main Authors: Sbicca, Lola, González, Alejandro López, Gresika, Alexandra, Di Giorgio, Audrey, Closa, Jordi Teixido, Tejedor, Roger Estrada, Andréola, Marie-Line, Azoulay, Stéphane, Patino, Nadia
• Format: Article
• Language: English
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c7cp03726k

The impact of the amino-acid side-chain length on peptide-RNA binding events has been investigated using HIV-1 Tat derived peptides as ligands and the HIV-1 TAR RNA element as an RNA model. Our studies demonstrate that increasing the length of all peptide side-chains improves unexpectedly the binding affinity ( K D ) but reduces the degree of compactness of the peptide-RNA complex. Overall, the side-chain length appears to modulate in an unpredictable way the ability of the peptide to compete with the cognate TAR RNA partner. Beyond the establishment of non-intuitive fundamental relationships, our results open up new perspectives in the design of effective RNA ligand competitors, since a large number of them have already been identified but few studies report on the modulation of the biological activity by modifying in the same way the length of all chains connecting RNA recognition motives to the central scaffold of a ligand. The impact of the amino-acid side-chain length on peptide-RNA binding events has been investigated using HIV-1 Tat derived peptides as ligands and the HIV-1 TAR RNA element as an RNA model.