title: Binding of Ru(terpyridine)(pyridine)dipyridophenazine to DNA studied with polarized spectroscopy and calorimetry.
abstract: Linear and circular dichroism (LD and CD) spectroscopy as well as isothermal titration calorimetry (ITC) have been used to investigate the interaction of Ru(tpy)(py)dppz(2+) (tpy = 2,2':6',2''-terpyridyl; py = pyridine; dppz = dipyrido[3,2-a:2'3'-c]phenazine) with DNA, providing detailed information about the DNA binding thermodynamics and binding geometry of the metal complex. Flow LD, CD and isotropic absorption indicate that Ru(tpy)(py)dppz(2+) bind to DNA from the minor groove with the dppz ligand intercalated between base pairs, very similar to its chiral structural isomers Δ- and Λ-Ru(bpy)2dppz(2+) (bpy = 2,2'-bipyridine). A simple cooperative binding model with one binding geometry provide an excellent fit for calorimetric and absorption titration data. The values of the neighbor interaction thermodynamic parameters for Ru(tpy)(py)dppz(2+) suggest that complexes bound contiguously prefer to have their tpy ligands oriented towards the same strand.
authors.affiliation: Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden. marann@chalmers.se lincoln@chalmers.se.
authors.forename: Anna K F
authors.initials: AK
authors.lastname: Mårtensson
authors.forename: Per
authors.initials: P
authors.lastname: Lincoln
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry; D002151:Calorimetry; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D010619:Phenazines / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D056831:Coordination Complexes; D010619:Phenazines; D015082:2,2'-Dipyridyl; D012428:Ruthenium; D004247:DNA