title: Initiation of synthesis of N-terminal acetylated histones with methionine.
abstract: The studies presented were undertaken to clarify the unsettled question whether the synthesis of histones with a N-acetylserine residue at the amino terminal end is initiated with methionine. Histones were synthesized in vitro in a rabbit reticulocyte lysate, primed with a mRNA preparation from ascites cells. Initiation of polypeptide synthesis was investigated by using N-formyl[35S]met-tRNAfMet from yeast to label the N-termini. N-Formylmethionine was incorporated into histones H1 and H4 whose N-terminal amino acid is alpha-N-acetylserine. By comparison of tryptic peptides derived from these two histones labeled either with methionine or formylmethionine and from Edman degradation it is shown that N-terminal acetylated histones are initiated with methionine, as is the case for other eukaryotic and bacterial proteins.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004926:Escherichia coli / Q000378:metabolism; D006657:Histones / Q000096:biosynthesis*; D008715:Methionine / Q000378:metabolism*; D051379:Mice; D009374:Neoplasms, Experimental; D010446:Peptide Fragments / Q000032:analysis; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D006657:Histones; D010446:Peptide Fragments; D012333:RNA, Messenger; D008715:Methionine