Metallized DNA

Molecular mechanics and dynamics studies of metal-nucleotide and metal-DNA interactions to date have been limited almost exclusively to modeling the interactions involving platinum-based anticancer drugs. As with metal-amino-acid complexes, there have been surprisingly few molecular mechanics studies of simple metal-nucleotide complexes that provide a means of deriving reliable force field parameters. A study of bis(purine)diamine-platinum(II) complexes successfully reproduced the structures of such complexes and demonstrated how steric factors influenced the barriers to rotation about the Pt(II)-N(purine) coordinate bonds and interconversion of the head-to-head (HTH) to head-to-tail (HTT) isomers (Fig. 12.4)[2011. In the process, force field parameters for the Pt(II)/nucleotide interactions were developed. A promising new approach involving the use of ab-initio calculations to calculate force constants has been applied to the interaction between Pt(II) and adenine[202]. 

Various articles in Metal-DNA-Chemistry, T. D. Tullius, Ed., ACS Symposium Series 402, American Chemical Society, Washington, DC, 1989. 

Mn (0.97, 0.81) Co (0.72) Mg (0.86), and Al (0.58). The solvent exchange rates (Kex S 1) for inner-sphere water molecules in metal ions are Al(10°) Mg (105) Co (105 5), and Mn(106 7) [21].The order of increasing rate constants in acidic solution is, Al Ligand exchange rates take on special importance for Al because they are slow and the system may not be at equilibrium. Mg, Mn, and Co have around 105 faster exchange rate over Al. These differential characteristics of the metals play a crucial role in metal-DNA interactions. 

Table 4. Binding constants of some metal-DNA complexes...

The sensitive emission properties of [Ru(phen)2(dppz)]2+ and its derivatives make these complexes ideal electron donors in the study of DNA-mediated electron transfer. Because luminescence is due to intercalated species, our photophysical studies will probe only those complexes bound to DNA. The steady-state and time-resolved luminescence assists also in characterizing novel metal/DNA assemblies. 

Table IV. Luminescent Intensities of Covalent Metal-DNA Intercalation Complexes...

Figure 4 Schematic representation of a doubly metallated DNA duplex used to probe photoinduced electron transfer in DNA (26).

Metallized DNA layer on mica substrate is shown by images of the SPM topography in Fig. 2a. The surface of the sample is covered by comparatively smooth coating (dark background in Fig. 2a) and separated aggregates on the top... 

Hadjiliadis, N. and Sletten, E. (eds) (2009) Metal Complex — DNA Interactions, Wiley-Blackwell, Oxford, UK. Overviews metal-DNA interactions and mechanisms, metallodrugs and toxicity includes a deep coverage of cisplatin. 

Tullius, T. D., ed. Metal-DNA Chemistry. American Chemical Society Symposium Series no. 402. Washington, D.C. American Chemical Society, 1989. 

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