Photolysis and thermolysis of platinum(IV) 2,2'-bipyridine complexes lead to identical platinum(II)-DNA adducts.
Two Pt(IV) and two Pt(II) complexes containing a 2,2'-bipyridine ligand were treated with a short DNA oligonucleotide under light irradiation at 37°C or in the dark at 37 and 50°C. Photolysis and thermolysis of the Pt(IV) complexes led to spontaneous reduction of the Pt(IV) to the corresponding Pt(II) complexes and to binding of Pt(II) 2,2'-bipyridine complexes to N7 of guanine. When the reduction product was [Pt(bpy)Cl(2)], formation of bis-oligonucleotide adducts was observed, whereas [Pt(bpy)(MeNH(2))Cl](+) gave monoadducts, with chloride ligands substituted in both cases. Neither in the dark nor under light irradiation was the reductive elimination process of these Pt(IV) complexes accompanied by oxidative DNA damage. This work raises the question of the stability of photoactivatable Pt(IV) complexes toward moderate heating conditions.
Loup
Christophe
C
CNRS, Laboratoire de Chimie de Coordination, 205 route de Narbonne, 31077 Toulouse, France.
Tesouro Vallina
Ana
A
Coppel
Yannick
Y
Létinois
Ulla
U
Nakabayashi
Yasuo
Y
Meunier
Bernard
B
Lippert
Bernhard
B
Pratviel
Geneviève
G
D015082:2,2'-Dipyridyl / Q000737:chemistry*; D000818:Animals; D001483:Base Sequence; D018736:DNA Adducts / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009944:Organoplatinum Compounds / Q000737:chemistry*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D010782:Photolysis; D012910:Snake Venoms / Q000201:enzymology; D013696:Temperature
D018736:DNA Adducts; D009944:Organoplatinum Compounds; D012910:Snake Venoms; D015082:2,2'-Dipyridyl; D010727:Phosphoric Diester Hydrolases