title: Phosphorylation of distinct regions of f1 histone. Relationship to the cell cycle.
abstract: The phosphorylation of different amino acids in distinct regions of f1 histone was studied in highly synchronized Chinese hamster cell populations (line CHO). The purified, 32P-labeled f1 histone was bisected into NH2-terminal and COOH-terminal fragments with N-bromosuccinimide. Tryptic phosphopeptides from these fragments were resolved using sequential high voltage electrophoretic steps on paper. No phosphorylation was observed in early G1-arrested cells. Interphase phosphorylation began in late G1 in the COOH-terminal portion of the molecule on serine. This event continued throughout S phase and persisted into mitosis. However, in mitosis additional phosphorylation was observed in the COOH-terminal portion of the molecule on threonine, and for the only time in the CHO cell cycle the NH2-terminal portion of the molecule was also phosphorylated on both serine and threonine. The peptide studies thus predicted that a minimum of four sites (two serine and two threonine) were phosphorylated in the f1 histone of mitotic CHO cells. This was confirmed using electrophoresis in long polyacrylamide gels.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002455:Cell Division; D002460:Cell Line; D006657:Histones / Q000378:metabolism*; D046911:Macromolecular Substances; D008938:Mitosis; D008970:Molecular Weight; D010085:Oxidative Phosphorylation; D010446:Peptide Fragments / Q000032:analysis; D006656:Protamine Kinase / Q000378:metabolism*; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D013997:Time Factors; D014357:Trypsin
chemical_list: D000596:Amino Acids; D006657:Histones; D046911:Macromolecular Substances; D010446:Peptide Fragments; D011494:Protein Kinases; D006656:Protamine Kinase; D014357:Trypsin