STABILIZATION OF POLY(DA)CENTER-DOT[POLY(DT)](2) TRIPLE-HELICAL DNA BY ACRIDINE-DERIVATIVES - ROLE OF SIDE-CHAIN IN THE TRIPLEX STABILIZATION

The conformation and stabilization effects of acridine derivatives 9-a minoacridine, an acridine with an aminoalkyl side chain, bis acridine (two acridines linked by an aminoalkyl side chain), and proflavin in t he tripler helical poly(dA).[poly(dT)](2) were investigated by optical spectroscopies. Based on the negative LD and weak positive CD in the acridine absorption wavelength region, we concluded that the acridine moiety of all derivatives are intercalated. We also examined the melti ng temperatures. Of all the compounds examined, the acridine with an a mino alkyl side chain had the strongest effect on the stabilization of the third strand of a poly (dA).[poly(dT)](2) tripler. The role of th e side chain, based on this observation, is discussed.