DNA binding by Ru(II)-bis(bipyridine)-pteridinyl complexes.
The interactions of five bis(bipyridyl) Ru(II) complexes of pteridinyl-phenanthroline ligands with calf thymus DNA have been studied. The pteridinyl extensions were selected to provide hydrogen-bonding patterns complementary to the purine and pyrimidine bases of DNA and RNA. The study includes three new complexes [Ru(bpy)(2)(L-pterin)](2+), [Ru(bpy)(2)(L-amino)](2+), and [Ru(bpy)(2)(L-diamino)](2+) (bpy is 2,2'-bipyridine and L-pterin, L-amino, and L-diamino are phenanthroline fused to pterin, 4-aminopteridine, and 2,4-diaminopteridine), two previously reported complexes [Ru(bpy)(2)(L-allox)](2+) and [Ru(bpy)(2)(L-Me(2)allox)](2+) (L-allox and L-Me(2)allox are phenanthroline fused to alloxazine and 1,3-dimethyalloxazine), the well-known DNA intercalator [Ru(bpy)(2)(dppz)](2+) (dppz is dipyridophenazine), and the negative control [Ru(bpy)(3)](2+). Reported are the syntheses of the three new Ru-pteridinyl complexes and the results of calf thymus DNA binding experiments as probed by absorption and fluorescence spectroscopy, viscometry, and thermal denaturation titrations. All Ru-pteridine complexes bind to DNA via an intercalative mode of comparable strength. Two of these four complexes--[Ru(bpy)(2)(L-pterin)](2+) and [Ru(bpy)(2)(L-allox)](2+)--exhibit biphasic DNA melting curves interpreted as reflecting exceptionally stable surface binding. Three new complexes--[Ru(bpy)(2)(L-diamino)](2+), [Ru(bpy)(2)(L-amino)](2) and [Ru(bpy)(2)(L-pterin)](2+)--behave as DNA molecular "light switches."
Dalton
Shannon R
SR
Department of Chemistry, Bryn Mawr College, Bryn Mawr, PA 19010, USA.
Glazier
Samantha
S
Leung
Belinda
B
Win
Sanda
S
Megatulski
Courtney
C
Burgmayer
Sharon J Nieter
SJ
D015082:2,2'-Dipyridyl / Q000737:chemistry*; D000042:Absorption; D000818:Animals; D002417:Cattle; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D046032:Microscopy, Energy-Filtering Transmission Electron; D009691:Nucleic Acid Denaturation; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011621:Pteridines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D055672:Static Electricity; D044366:Transition Temperature
D009942:Organometallic Compounds; D011621:Pteridines; D015082:2,2'-Dipyridyl; D012428:Ruthenium; D004247:DNA; C427203:calf thymus DNA