title: Interaction between the DNA model base 9-ethylguanine and a group of ruthenium polypyridyl complexes: kinetics and conformational temperature dependence.
abstract: The binding capability of three ruthenium polypyridyl compounds of structural formula [Ru(apy)(tpy)Ln-](ClO4)(2-n) [1a-c; apy = 2,2'-azobis(pyridine), tpy = 2,2':6',2''-terpyridine, L = Cl, H2O, CH3CN] to a fragment of DNA was studied. The interaction between each of these complexes and the DNA model base 9-ethylguanine (9-EtGua) was followed by means of 1H NMR studies. Density functional theory calculations were carried out to explore the preferential ways of coordination between the ruthenium complexes and guanine. The ruthenium-9-EtGua adduct formed was isolated and fully characterized using different techniques. A variable-temperature 1H NMR experiment was carried out that showed that while the 9-EtGua fragment was rotating fast at high temperature, a loss of symmetry was suffered by the model base adduct as the temperature was lowered, indicating restricted rotation of the guanine residue.
authors.affiliation: Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Leiden, The Netherlands.
authors.forename: Eva
authors.initials: E
authors.lastname: Corral
authors.forename: Anna C G
authors.initials: AC
authors.lastname: Hotze
authors.forename: Alessandra
authors.initials: A
authors.lastname: Magistrato
authors.forename: Jan
authors.initials: J
authors.lastname: Reedijk
mesh_terms: D002621:Chemistry / Q000379:methods; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011725:Pyridines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D012984:Software; D013696:Temperature; D013997:Time Factors
chemical_list: D011725:Pyridines; D006147:Guanine; D012428:Ruthenium; C014542:9-ethylguanine; D004247:DNA