Histone H3 as a redox switch in the nucleosome core particle: insights from molecular modeling
Histone H3 as a redox switch in the nucleosome core particle: insights from molecular modeling
Karami, Y.; Gonzalez Aleman, R.; Duch, M.; Qiu, Y.; Kedjar, Y.; Bignon, E.
AbstractHistones post-translational modifications are major regulators of the chromatin dynamics. Understanding the structural signature of these marks in the nucleosome context is of major importance to unravel their mechanisms of action and open perspectives for the development of new therapies. In this work, we rely on multi-microseconds molecular dynamics simulations and advanced structural analysis to unravel the effect of two modifications of the histone H3: S-sulfenylation and S-nitrosylation. These oxidative modifications are known to target the cysteine 110 on the histone H3, but there was no data about their effect on the nucleosome dynamics. We show that in a nucleosome core particle, S-sulfenylation and S-nitrosylation exhibit different structural signatures, which could suggest that they play a different role in the regulation of the nucleosome dynamics. While S-sulfenylation destabilizes the dyad and could be involved in the nucleosome disassembly, S-nitrosylation mainly induces DNA flexibility at its entry/exit point, most probably favoring breathing/unwrapping phenomena. Our results highlight the fine tune link between the chemical nature of histone core post-translational modifications and their impact on such a large architecture as the nucleosome. They also provide new insights into the regulatory mechanisms of histone oxidative modifications, about which very little is known so far.