title: Contact site of histones 2A and 2B in chromatin and in solution.
abstract: Irradiation of isolated nuclei or of a complex of histones 2A (H2A) and 2B (H2B) with ultraviolet light produces a covalent cross-link between H2A and H2B. Sequence analysis of the peptides isolated from the H2A-H2B dimer formed in solution and in nuclei demonstrated that both dimers are produced through the covalent linkage of Tyr-40 of H2B and Pro-26 of H2A. Tyrosyl residues proximal to Tyr-40 did not produce a cross-link with H2A, thereby indicating that strict conformational parameters are required for production of the H2A-H2B cross-link. We conclude that the precise juxtaposition of Tyr-40 of H2B and Pro-26 of H2A in this region of the H2A/H2B contact site is not altered upon interaction of these histones with H3 and H4 (tetramer), DNA, or other chromosomal components during nucleosome assembly.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002268:Carboxypeptidases; D002417:Cattle; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D002918:Chymotrypsin; D006657:Histones / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects; D046911:Macromolecular Substances; D010446:Peptide Fragments / Q000032:analysis; D012996:Solutions; D013950:Thymus Gland / Q000378:metabolism; D014357:Trypsin; D014466:Ultraviolet Rays
chemical_list: D002843:Chromatin; D006657:Histones; D046911:Macromolecular Substances; D010446:Peptide Fragments; D012996:Solutions; D002268:Carboxypeptidases; D002918:Chymotrypsin; D014357:Trypsin