AP-site does not introduce significant distortions into the DNA structure in the nucleosomes in vitro

DNA damage leads to distortion of the B-form structure of its double helix. Recognition of such distortion by DNA repair proteins is an important step in initiating this process. The nucleosome structure imposes limitations on the mobility and plasticity of DNA geometry in its composition. When studying the interactions of repair proteins with DNA in the composition of the nucleosome, the main question lies in realizing the DNA structure characteristic of the damage itself in a particular context. Additionally, the DNA duplex in the nucleosome has a regular contact profile with histones corresponding to the pitch of the DNA helix. Changes in this profile allow us to determine changes in the DNA structure. This profile correlates with the availability of relevant nucleotides for interacting with DNA-binding proteins. Using the footprinting method, we showed that the presence of an apurine/apiridine site within the second-third turn of the spiral from the 5'-end in the nucleosomal DNA did not have a significant effect on the profile of DNA-histone contacts.