Reactions of model proteins with aurothiomalate, a clinically established gold(I) drug: The comparison with auranofin.

Aurothiomalate (AuTm) is an old, clinically established, antiarthritic gold drug that is currently being reconsidered as a candidate drug for cancer treatment and for other therapeutic indications within a more general drug repositioning program. As the biological effects of gold drugs seem to be mediated, mainly, by their interactions with protein targets we have analyzed here, in detail, the metalation patterns produced by aurothiomalate in a few model proteins. In particular, the reactions of aurothiomalate with the small proteins ribonuclease A, cytochrome c and lysozyme were explored through ESI MS (electrospray ionization mass spectrometry) analysis.

Experimental and molecular modeling studies of the interaction of the polypyridyl Fe(II) and Fe(III) complexes with DNA and BSA.

Two mononuclear iron complexes, [Fe(tppz)₂](PF₆)₂·H₂O (1) and Fe(tppz)Cl₃·2CHCl₃ (2) where tppz is (2,3,5,6-tetra(2-pyridyl)pyrazine), have been synthesized and characterized by elemental analysis, spectroscopic methods (UV-Vis and IR) and single crystal X-ray structure analysis. The interaction of (1) as the nitrate salt ([Fe(tppz)₂](NO₃)₂) with calf-thymus DNA (CT-DNA) has been monitored by UV-Vis spectroscopy, competitive fluorescence titration, circular dichroism (CD), voltammetric techniques, viscosity measurement, and gel electrophoresis. Gel electrophoresis of DNA with [Fe(tppz)₂](NO₃)₂ demonstrated that the complex also has the ability to cleave supercoiled plasmid DNA.

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.

Binding interaction of a water soluble cobalt(II) complex of a Schiff base, SF, (SF = N,N'-bis{5-[(triphenylphosphonium chloride)-methyl] salicylidine}-o-phenylenediamine) with calf thymus DNA (CT-DNA) has been investigated. The intrinsic binding constant (K(b) = 5 x 10(4) M(-1)) was determined. In comparison with previous study the results indicate that the binding affinity of SF is stronger than its Co(II) complex.

DNA binding and gel electrophoresis studies of a copper (II) complex containing mixed aliphatic and aromatic dinitrogen ligands.

The interaction of a novel mixed ligand copper (II) complex, [Cu(N-N)(L)(EtOH)](NO(3))(2) . 2H(2)O, in which N-N indicates 2,9-dimethyl-1,10-phenanthroline and L indicates N,N-dimethyltrimethylenediamine with calf thymus DNA was investigated by absorption, circular dichroism, voltammetric, and viscosimetric techniques. The absorption spectra of the complex with calf thymus DNA showed a marked hypochromism in the pi --> pi* and metal to ligand charge transfer (MLCT) transitions, with no obvious red shift attributed to a partial intercalation.

In vitro study of DNA interaction with a water-soluble dinitrogen schiff base.

The present study investigates the binding interaction between a water-soluble Schiff base, N,N'-bis{5-[(triphenylphosphonium chloride)-methyl]salicylidine}-o-phenylenediamine (SF), and calf thymus DNA (CT-DNA) using emission, absorption, circular dichroism, and viscosity studies. In fluorimetric studies, the dynamic enhancement constant (K(D)) and bimolecular enhancement constant (K(B)) were calculated at different temperatures and demonstrated that fluorescence enhancement is not initiated by a dynamic process, but instead by a static process that involves complex DNA formation in the ground state. Further, the enthalpy and entropy of the reaction between SF and CT-DNA showed that the reaction is exothermic and enthalpy-favored (DeltaH = -153.