Interaction of octahedral ruthenium(II) polypyridyl complex [Ru(bpy)2(PIP)]2 + with poly(U)·poly(A)*poly(U) triplex: Increasing third-strand stabilization of the triplex without affecting the stability of the duplex

The binding of [Ru(bpy)2(PIP)]2 + (bpy = 2.2′-bipyridine, PIP = 2-phenyl-1H-imidazo[4,5-f] [1,10]phenanthroline) to poly(U).poly(A)*poly(U) triplex has been investigated. Results suggest [Ru(bpy)2(PIP)]2 + binding with the triplex is favored by the Hoogsteen paired strand, thereby it increases third-strand stabilization of the triplex without affecting the stability of the duplex.179