Novel synthesis of a tetra-acridinyl peptide as a new DNA polyintercalator

Tetra-acridinyl peptide 2 was synthesized from Fmoc-Lys(Boc)-OH and Fmoc-Lys(Acr)-OH (1) with the peptide synthesizer. The CD measurement suggested that 2 forms a special organized structure by itself in buffered solution. Peptide 2 binds to double stranded DNA with a very large affinity constant, which is 10(3)-times larger than that of quinacrine. Spectrophotometric and hydrodynamic studies suggested that all of the acridinyl parts of 2 contribute to the intercalating interaction for the DNA binding. Our finding in this experiment demonstrates that polyintercalators such as 2 can be assembled quickly by the automated synthesizer.