title: Preferred orientation in an angled intercalation site of a chloro-substituted Λ-[Ru(TAP)2(dppz)]2+ complex bound to d(TCGGCGCCGA)2.
abstract: The crystal structure of the ruthenium DNA 'light-switch' complex Λ-[Ru(TAP)2(11-Cl-dppz)](2+) (TAP=tetraazaphenanthrene, dppz=dipyrido[3,2-a':2',3'-c]phenazine) bound to the oligonucleotide duplex d(TCGGCGCCGA)2 is reported. The synthesis of the racemic ruthenium complex is described for the first time, and the racemate was used in this study. The crystal structure, at atomic resolution (1.0 Å), shows one ligand as a wedge in the minor groove, resulting in the 51(°) kinking of the double helix, as with the parent Λ-[Ru(TAP)2(dppz)](2+). Each complex binds to one duplex by intercalation of the dppz ligand and also by semi-intercalation of one of the orthogonal TAP ligands into a second symmetrically equivalent duplex. The 11-chloro substituent binds with the major component (66%) oriented with the 11-chloro substituent on the purine side of the terminal step of the duplex.
authors.affiliation: Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK.
authors.forename: James P
authors.initials: JP
authors.lastname: Hall
authors.forename: Hanna
authors.initials: H
authors.lastname: Beer
authors.forename: Katrin
authors.initials: K
authors.lastname: Buchner
authors.forename: David J
authors.initials: DJ
authors.lastname: Cardin
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Cardin
mesh_terms: D001665:Binding Sites; D002713:Chlorine / Q000737:chemistry*; D007364:Intercalating Agents / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D007364:Intercalating Agents; D009841:Oligonucleotides; D002713:Chlorine; D012428:Ruthenium
keywords: DNA; intercalation; ruthenium