A reversible B-A transition of DNA duplexes induced by synthetic cationic copolymers.

Although the B-form duplex is the canonical DNA structure, the A-form duplex plays critical roles in controlling gene expression. Here, reversible B-A transitions of DNA duplexes were induced by synthetic cationic and anionic polymers. Thermodynamic analysis demonstrated that the B-A transition was regulated by the dehydration of the DNA duplex caused by polymer binding.