Acceleration of DNA strand exchange reaction by cationic polymers

In previous reports, we have demonstrated that the cationic comb-type copolymers (PLL-g-Dex) having a poly-L-lysine main chain and dextran side chains stabilized DNA duplex and triplex. Furthermore, the copolymer was found to accelerate more than 20,000 folds strand exchange reaction between 20 bp duplex and its homologous single strand (1). This study was designed to inspect structural factor of polycationic moieties in acceleration effects. To this end, polypeptides containing lysine or arginine moieties as cationic groups were examined in their potency to accelerating strand exchange reaction. It was shown that arginine-rich peptide showed higher accelerating effect than lysine peptide when total positive charges of peptides were kept constant.