A dynamic view of histone tails interaction with clustered abasic sites in a nucleosome core particle

Abstract

Apurinic/apyrimidinic sites are the most common DNA damage under physiological conditions. Yet, their structural and dynamical behavior within nucleosome core particles has just begun to be investigated, and show dramatic differences with the one of abasic sites in B-DNA. Clusters of two or more abasic sites are repaired even less efficiently and hence constitute hotspots of high mutagenicity notably due to enhanced double-strand breaks formation. Based on a X-ray structure of a 146-bp DNA wrapped onto a histone core, we investigate the structural behavior of two bistranded abasic sites positioned at mutational hotspots along microsecond-range molecular dynamics simulations. Our simulations allow us to probe histone tails interactions at clustered abasic sites locations, with a definitive assignment of the key residues in-volved in the NCP-catalyzed formation of DNA-protein cross-linking in line with recent experimental findings, and pave the way towards a systematic assessment of histone tails response to DNA lesions.