Localization of two antigenic determinants in histone H4.

Four overlapping synthetic peptides corresponding to the carboxy-terminal region 80-102 of histone H4 were prepared by solid-phase peptide synthesis. Their antigenic activity was analysed by inhibition of the H4-anti-H4 reaction in complement fixation and enzyme-linked immunosorbent assay. One antigenic determinant was localized in residues 88-96 of the H4 molecule. No antigenic activity was found in peptides 80-89 and 97-102. Antibodies induced by peptide 85-102 were found to bind to free H4 in solution but not to chromatin subunits, suggesting a lack of accessibility of the C-terminal region of H4 in nucleosomes. A second epitope was found to be situated in the N-terminal region 1-53 of histone H4.