A New CoII Complex as a Bulge-Specific Probe for DNA

Abstract

Bulge cleavage of two or three bases occurs when a DNA substrate is specifically cleaved oxidatively by [Co (tfa) (happ)] (see picture). Hydrogen peroxide is necessary for the activation of this octahedral complex, which suggests that hydroxyl radicals are the reactive species. The complex has no significant reactivity towards the corresponding sequence in a single-stranded DNA region, and it exhibits only a low affinity towards double-stranded DNA. happ=macrocyclic ligand based on 1,10-phenanthroline, tfa=trifluoroacetate.

DNA binding and DNA cleavage studies of a water soluble cobalt(II) complex containing dinitrogen Schiff base ligand: The effect of metal on the mode of binding

“…Some of the previous reports show that hexamine cobalt complexes induce DNA condensation [23,24] and can be used to probe RNA hairpins [25]. Some of the cobalt(II) complexes, such as [Co(tfa)(happ)], are known to function as specific probe for DNA bulges due its ability to cleave DNA specifically [26].…”

Synthesis, characterization, X-ray structure and DNA photocleavage by cis-dichloro bis(diimine) Co(III) complexes

“…Vaidyanathan and Nair [15] have reported that cis-[Cr(dppz) 2 Cl 2 ] + complex binds to DNA by intercalation with a binding constant of 10 7 M À1 . Co (III) Xaa-Xaa-His-metallopeptides induce DNA strand scission upon photoirradiation [16] while oxygen/H 2 O 2 activated Co(II) complex of a macrocyclic ligand based on 1,10-phenanthroline acts as a bulge-specific probe for DNA [17] and vanadyl(IV) complexes derived from Nsalicylidene a-amino acids serve as efficient DNA photocleavage agents [18].…”

Synthesis, DNA-binding and photocleavage studies of cobalt(III) mixed-polypyridyl complexes: [Co(phen)2(dpta)]3+ and [Co(phen)2(amtp)]3+

“…Varying the substitutive group or substituent position in the intercalative ligand can create some interesting differences in the space configuration and the electron density distribution of transition metal complexes, which will result in some differences in spectral properties and the DNA-binding behaviors of the complexes and will be helpful to more clearly understand the binding mechanism of transition metal complexes to DNA [6][7][8]. However, such studies mainly focus on the interaction of Ru(II) complexes with DNA, and the reports on the other metal complexes are relatively limited [9][10][11][12][13][14][15][16][17]. Our group has been synthesized some cobalt(III) mixedpolypyridyl complexes, which bind to DNA through an intercalative mode and promote photocleavage of plasmid pBR 322 DNA [14][15][16][17].…”