ON THE INTERACTION OF [RU(PHEN)(2)DPPZ](2-A-2',3'-C]PHENAZINE) WITH DIFFERENT OLIGONUCLEOTIDES() (DPPZ = DIPYRIDO[3,2)

Luminescent titrations have been performed on a ''molecular light swit ch for DNA'', [Ru(phen)(2)dppz](2+) (dppz = dipyrido[3,2-a:2',3'-c]phe nazine), with several different 16-bp oligonucleotides having sequence -directed shape (''straight'', ''bent'' and ''kinked''). Binding const ants and binding site sizes are consistent with metal complex intercal ation for all oligonucleotides. The emission maxima and relative inten sities upon saturation are consistent with trends found for long DNAs based on relative GC content. [Ru(phen)2dppz]2' has a significantly hi gher binding constant and larger site size for the ''kinked'' oligonuc leotide than for the ''straight'' and ''bent'', suggesting that local DNR deformation plays a role in the interaction of metallointercalator s with DNA. (C) 1998 Elsevier Science Inc. All rights reserved.