[Modeling of mechanochemical DNA cleavage by action of ultrasound].

This study offers a simulation of the stretching dynamics of a double-stranded DNA fragment in the high-gradient flow of fluid near collapsing cavitation bubbles. Calculated profiles of elastic tension along the model of a polymer fragment were used to estimate the rates of mechanochemical cleavage at different positions of DNA restriction fragments. The resulting cleavage rate profiles are qualitatively consistent with the experimentally observed profiles of ultrasonic cleavage rates of DNA restriction fragments, which are position-dependent. The proposed model also relates the sequence specificity of ultrasonic DNA cleavage, which was experimentally detected earlier, to the peculiarities of sequence-specific conformational dynamics of ß-D-deoxyribose in the B-form double helix. A quantitative assessment of the ultrasonic DNA cleavage rates for different conformational states of ß-D-deoxyribose derived from the proposed model qualitatively agrees with the experimental data.

[Analysis of binding of oligonucleotides on microarrays: hybridization energy isotherms].

The study reports a thermodynamic model describing microarray oligo-target hybridization. The relationship between hybridization signal intensity and Gibbs free energy change for oligo-target duplex formation was our function of interest. The behavior of this function that we called energetical hybridization isotherm in response to target concentration change was modeled considering different ratios of oligo-probes/target concentrations. The results of modeling were compared with the relevant and currently available from literature microarray adsorption experiment.

[Analysis of DNA-ligand binding in solution and on biochips].

Ligand binding to DNA, as well as to microarrays, requires a system approach to description and analysis. This type of approach implies a fixed sequence of operations. Firstly, it is necessary to make a description of a binding scheme that realizes ligand and polymer in common spatial way. Secondly, a physical model of binding is required. Thirdly, a mathematical binding model should be constructed on the basis of the binding scheme and the physical model of binding. Every analysis of experimental data needs this preliminary work. A mathematical apparatus and classification of binding models have to follow on. Classification of different binding isotherms by different binding models is the direct problem. The inverse problem is a reconstruction of parameters of a binding model by experimental binding isotherm curves. The inverse problem can only be solved after solving the direct problem. An example of classification of binding models by oligonucleotides or proteins binding cooperativity and polymer properties like homo- or heteropolymer is presented.