Ni(II)-Histone H4 interactions: structural modifications

It is known that nickel participates to carcinogenic processes through mechanisms interfering with several cellular targets; among them, histone H4 has been recently identified. Histones are nuclear proteins that package and organize DNA into nucleosomes and chromatin, but they are also involved in gene regulation and transcription. By undergoing post-translational modifications, such as acetylation, methylation and phosphorylation, they change chromatin structure helping gene transcription or inhibition. Nickel showed to bein vivoa potent inhibitor of histone H4 acetylation. Acetylation causes important structural modifications in histones: for instance, it increases the α-helix content, thus decreasing the length of the histone tail and affecting the transcription mechanisms.