Synthesis, characterization and DNA binding studies of two cyclopentadienyl ruthenium(II) complexes with amino acid ligands

Abstract

Two new half-sandwich cyclopentadienyl ruthenium(II) complexes containing a-amino acids, [CpRu-(PPh 3 ) 2 (Ser)] (Ser = L-serine) and [CpRu(PPh 3 )(Met)] (Met = L-methionine), were synthesized and characterized by physicochemical methods. Interactions of these two complexes with calf thymus DNA were investigated by UV-Vis absorption spectroscopy, emission spectroscopy and competitive binding studies. The results indicate that both complexes can interact with DNA, leading to the damage of the double helix. [CpRu(PPh 3 ) 2 (Ser)] binds to DNA by intercalation, while the binding mode for [CpRu(PPh 3 )(Met)] is more complicated due to the formation of an EB-DNA-complex (EB = ethidium bromide). The affinity of the Met complex for DNA is stronger than that of the Ser complex, which could be due to groove-surface combination or electrostatic interaction in addition to intercalative binding.

Altered DNA Binding and Amplification of Human Breast Cancer Suppressor Gene BRCA1 Induced by a Novel Antitumor Compound, [Ru(η6-p-phenylethacrynate)Cl2(pta)]

“…The absorption intensities of ethaRAPTA were shown to successively increase and exhibited hyperchromism. This result is similar to that reported for the interaction of other types of ruthenium(II) complexes [ 26 – 29 ]. The intrinsic binding constant ( K b ) of the complex with the BRCA1 fragment was determined as 2.34 × 10 6 M −1 from the changes in absorbance at 340 nm using the Equation 1 (see Experimental Section).…”

Mechanistic study on substitution reaction of a citrato(p-cymene)Ru(ii) complex with sulfur-containing amino acids

“…While syntheses and properties of some arene ruthenium(II) complexes with amino acids have been reported so far, [18][19][20][21][22][23][24][25][26][27] it is presently necessary for comprehensible mechanistic studies to adopt simple reaction systems in which one reactant complex gives only one product complex without any by-product under any aqueous conditions such as pH, molar ratio of reactants, coexisting ions, etc. in order to keep observation of an identical reaction.…”

Half-sandwich complexes of ruthenium, osmium, rhodium and iridium with dl-methionine or S-methyl-l-cysteine: a solid state and solution equilibrium study

“…17 Adding a strongly coordinating monodentate ligand to the system in [(h 5 -Cp)Ru II (PPh 3 )(met)] (N, O) coordination of the amino acid was suggested according to the IR data. 18 Based on the formation of stable complexes sequence-selective detection of Met-containing oligopeptides was also demonstrated with the use of the [(h 5 -Cp*)Rh III type building block as chemosensor. 19 In a recent work a combined NMR and MS study on the interaction of [(h 6 -p-cym)RuCl 2 ] 2 and methionine in aqueous solution indicated the formation of a (S, N, O) coordinated major complex 48 h being necessary to reach equilibrium in solution.…”