Background
The nucleosome, made up of four core histone proteins (H2A, H2B, H3, and H4),is the primary building block of chromatin. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries. Featuring a main globular domain and a long N-terminal tail, H3 is involved with the structure of the nucleosomes of the 'beads on a string' structure. Histone proteins are highly posttranslationally modified however Histone H3 is the most extensively modified of the five histones. It is an important protein in the emerging field of epigenetics, where its sequence variants and variable.Protein citrullination is an emerging PTM that results from the conversion of peptidyl arginine to peptidyl citrulline.Due to the exchange of an imine for a carbonyl group, this reaction is referred to as deimination. This PTM is catalyzed by the calcium-regulated PAD family of enzymes. Dysregulated PAD expression and aberrant protein citrullination have been implicated in numerous human diseases such as osteosarcoma, colorectal cancer, esophagus cancer and breast cancer.
Cellular location
Nucleus
