²³Na NMR Study of the Interaction Between DNA and the Platinum (II) Compounds: Cis-DDP, Trans-DDP and TDP

Abstract

The interaction of calf thymus DNA with cis-DDP, trans-DDP and TDP was studied by 23Na NMR in aqueous solutions at pH=7.0, with Pt(II) compounds/DNA(P) (P=Phosphate) molar ratios r increasing from 0 till to 1P. 23Na NMR results are interpreted on one hand, with the help of a " two states model " with R(F) and R(B) relaxation rates, and, on the other hand, using the " entropy of fluctuations " concept developed by Lenk. We have established that, for the studied platinum compounds, the preference to interact with DNA phosphate sites -interpreted as a perturbation of the counterions environment- is in a decreasing order: TDP >> cis-DDP > trans-DDP. These results are discussed with regard to the interaction of DNA with the hard bication Mg++ and the soft bication Cu++.

Synthesis, characterization and DNA binding properties of oligopyridine-ruthenium(II)-amino acid conjugates

“…3(i)). This interaction causes an irreversible modification of the DNA polyanion, replacing the sodium cations and it is similar with that observed at the cases of cis-PtCl 2 (NH 3 ) 2 and trans-PtCl 2 (NH 3 ) 2 [45]. However, in the case of complexes (5) and (6), at the same ratios (r = 0.5), the narrowing of the 23 Na signal is smaller (13 and 12 Hz, respectively), probably due to their lower positive charge.…”

Solid-phase synthesis, characterization and DNA binding properties of the first chloro(polypyridyl)ruthenium conjugated peptide complex

“…1 H NMR, 23 Na NMR and 31 P NMR measurements were performed on a Bruker 300 DPX spectrometer operating at 300.13 MHz, at 121.49 MHz and at 79.39 MHz for 1 H, 31 P and 23 Na NMR, respectively. 1-D and 2-D spectra were recorded in MeOD-d 4 and D 2 O with 2,2-dimethyl-2-silapentane-5-sulfonate (DSS) as internal standard.…”

“…27,28 3.2.2 23 Na and 31 P NMR spectroscopy. 31 P NMR spectroscopy is sensitive to conformational changes 29 and interactions of metal complexes with DNA 30 because of the potential sensitivity of 31 P chemical shifts to phosphate bonds.…”

Exocyclic oxygen atoms of platinated nucleobases as binding sites for alkali metal ions †

“…This aspect has not attracted much attention in the past. 13 Despite the availability of several crystal structure analyses of DNA fragments (intrastrand 14, 15 and interstrand 16 GpG adducts of cisplatin, [Pt(NH 3 ) 2 Cl 2 ]), nothing is known about the possible role and location of alkali counter ions within such DNA lesions. The difficulty to identify partially occupied positions of Na ϩ ions and to differentiate them from water molecules in a distorted DNA fragment appears to be even more severe than in a regular DNA fragment.…”