The interaction of quinacrine with triple-stranded poly(U).poly(A).poly(U).

The interaction of the antimalarial drug quinacrine (QAC) with triple-stranded poly(U).poly(A).poly(U)(poly(U.A.U)) has been investigated by absorption, fluorescence and circular dichroism (CD) measurements. The results indicate that QAC binds to poly(U.A.U), as well as double-stranded poly (A).poly(U) (poly(A.U)) and poly(I).poly(C) (poly(I.C)). It is concluded that the acridine ring of QAC intercalates into successive U.A.U base-triplets from the minor groove, because the third-strand poly(U) in the major groove of poly(A.U) inhibits the binding of QAC to the major groove.