SELECTIVE STABILIZATION OF TRIPLEX DNA BY ANTHRAQUINONE SULFONAMIDE DERIVATIVES

A series of cationic anthraquinone derivatives was investigated for th eir ability to stabilize duplex and tripler DNA. Thermal denaturation experiments demonstrate that each of these compounds stabilizes the [p oly(dT). poly(dA)xpoly(dT)] tripler without significantly affecting th e [poly(dT). poly(dA)] duplex. The amount of stabilization is determin ed by the number and placement of the cationic substituents on the ant hraquinone skeleton. The stabilization arises primarily from higher af finity binding of the quinones to the tripler relative to the duplex s tructures. Phosphorescence quenching and viscometric titrations indica te that the quinones bind to the tripler by intercalation.