title: DNA cleavage activity of V IV O(acac)2 and derivatives.
abstract: The DNA cleavage activity of several beta-diketonate vanadyl complexes is examined. Vanadyl acetylacetonate, V(IV)O(acac)(2), 1, shows a remarkable activity in degrading plasmid DNA in the absence of any activating agents, air and photoirradiation. The cleaving activity of several related complexes V(IV)O(hd)(2) (2, Hhd=3,5-heptanedione), V(IV)O(acac-NH(2))(2) (3, Hacac-NH(2)=acetoacetamide) and V(IV)O(acac-NMe(2))(2) (4, Hacac-NMe(2)=N,N-dimethylacetoacetamide) is also evaluated. It is shown that 2 exhibits an activity similar to 1, while 3 and 4 are much less efficient cleaving agents. The different activity of the complexes is related to their stability towards hydrolysis in aqueous solution, which follows the order 1 approximately 2>>3 approximately 4. The nature of the pH buffer was also found to be determinant in the nuclease activity of 1 and 2. In a phosphate buffered medium DNA cleavage by these agents is much more efficient than in tris, hepes, mes or mops buffers. The reaction seems to take place through a mixed mechanism, involving the formation of reactive oxygen species (ROS), namely OH radicals, and possibly also direct cleavage at phosphodiester linkages induced by the vanadium complexes.
authors.affiliation: Departamento de Química, Bioquímica e Farmácia, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Butenko
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Tomaz
authors.forename: Ofelia
authors.initials: O
authors.lastname: Nouri
authors.forename: Esther
authors.initials: E
authors.lastname: Escribano
authors.forename: Virtudes
authors.initials: V
authors.lastname: Moreno
authors.forename: Sofia
authors.initials: S
authors.lastname: Gama
authors.forename: Vera
authors.initials: V
authors.lastname: Ribeiro
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Telo
authors.forename: João Costa
authors.initials: JC
authors.lastname: Pesssoa
authors.forename: Isabel
authors.initials: I
authors.lastname: Cavaco
mesh_terms: D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D053837:DNA Cleavage; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D006885:Hydroxybutyrates / Q000737:chemistry*; D007700:Kinetics; D018625:Microscopy, Atomic Force; D010422:Pentanones / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000737:chemistry
chemical_list: D006885:Hydroxybutyrates; D010422:Pentanones; D017382:Reactive Oxygen Species; C049529:acetyl acetonate; D004247:DNA; D006861:Hydrogen Peroxide