The molecular structure effect of cationic comb-type copolymers on nucleic acid chaperone activity.

We have shown that the cationic comb-type copolymers (CCCs) accelerate DNA hybridization and increase stability of DNA duplexes and triplexes. The CCCs were considered to act as "nucleic acid chaperones," promoting the formation of the most stable hybrids. In this study, CCCs with primary amino or guanidino groups were prepared to evaluate the effects of different cationic moieties upon the nucleic acid chaperone activity. CCCs having guanidino groups have higher accelerating effect on DNA strand exchange reactions than that having primary amino groups. It was suggested that some modes of interactions, such as hydrogen bonding, other than ionic interactions between the copolymers and DNAs may be involved upon the strand exchange activation.