Proteolytic Digestion Studies of Chromatin Core‐Histone Structure

Abstract
Trypsin digestion of chromatin results in a well‐defined set of limit peptides (P1‐P5) derived from the four core histones. Those from histones H3 and H4 have been identified. P1 is H3 residues 27‐129; P4 is H4 residues 18‐102 and P5 is H4 residues 20‐102. The N‐terminal sequences removed correlate well with the regions that undergo post‐synthetic acetylation and which show the greatest degree of sequence conservation. Autolytic digestion of chromatin releases a peptide (P1′) from H3 representing residues 21‐135. The implications of protease digestion of the higher order structure of chromatin are discussed.