Complete amino-acid sequence of calf-thymus histone 3.

Calf-thymus histone III is a single polypeptide chain of 135 residues (combined molecular weight of 15,324) with alanine at both the amino and carboxyl ends. The NH(2)-terminal region (Residues 1-53) of histone III is strongly basic (net charge of +18) and contains lysines-14 and -23, which are epsilon-N-acetylated in a fraction of the molecules, as well as lysines-9 and -27, which are partially epsilon-N-methylated. The COOH-terminal region (Residues 54-135) is only slightly basic (net charge of +4), contains most of the hydrophobic residues, and has a 29-residue sequence that lacks a basic residue. The two cysteines are in the nonbasic region at positions 96 and 110. A few sequence similarities of calf-thymus histone III with other histones have been noted.