ИСТИНА

DNA-protein interactions play crucial role in functioning of living systems, including genomes of all living organisms. Electron microscopy is a popular technique that is often used to study structures of DNA-protein complexes. To efficiently prepare samples of these complexes for EM one requires some prior knowledge of the binding strength between DNA and protein. To date a lot of methods for detecting protein-DNA interactions have been developed. One approach relies on fluorescently labeled molecules: upon interaction of the labeled binders the changes in the fluorescence intensity or polarization may be detected. Fluorescencebased methods allow for a quantitative estimate of binding constants directly in the bulk solution. In this work we describe an experimental protocol based of fluorescence polarization measurements and present a data processing algorithm (developed by us using Python programming language), which allows to estimate binding constants from the experimental data and accounts properly for the background signal and measurement uncertainties.