Synthesis of a l-lysine-based alternate alpha,epsilon-peptide: A novel linear polycation with nucleic acids-binding ability

A novel nucleic acid compaction device based on a positively-charged alpha,epsilon-poly-l-lysine was realized for the first time. The polycationic peptide was obtained by assembling Fmoc and Boc orthogonally protected l-lysine monomers by solid phase synthesis. The route to the novel polycation is very fast and convenient because it allows for the obtainment of the desired product in few synthetic steps exclusively employing Fmoc chemistry. The purification of the poly-amino acid was performed easily by RP-HPLC on C18 stationary phase while ESI-MS analysis confirmed the identity of the novel basic molecule. The structural characteristics of the novel water-soluble peptide, as well as the interaction with deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) have been investigated by circular dichroism (CD) and ultraviolet (UV) spectroscopy.