title: Active site amino acid sequence of the bovine O6-methylguanine-DNA methyltransferase.
abstract: An O6-methylguanine-DNA methyltransferase has been partially purified from calf thymus by conventional biochemical techniques. The enzyme was specifically radioactively labelled at the cysteine residue of the active site and further purified by attachment to a solid support. Following digestion with trypsin, a radioactive peptide containing the active site region of the protein was purified by size fractionation, ion exchange chromatography and reverse phase HPLC. The technique yielded an essentially homogeneous oligopeptide which was subjected to amino acid sequencing. The sequence adjacent to the acceptor cysteine residue of the bovine protein exhibits striking homology to the C-terminal methyl acceptor site of the E. coli Ada protein and the proposed acceptor sites of the E. coli Ogt and the B. subtilis Dat1 proteins.
authors.affiliation: Imperial Cancer Research Fund, Clare Hall Laboratories, Herts, UK.
authors.forename: B
authors.initials: B
authors.lastname: Rydberg
authors.forename: J
authors.initials: J
authors.lastname: Hall
authors.forename: P
authors.initials: P
authors.lastname: Karran
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D008780:Methyltransferases / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D019853:O(6)-Methylguanine-DNA Methyltransferase; D009841:Oligonucleotides; D010446:Peptide Fragments / Q000032:analysis; D013950:Thymus Gland / Q000201:enzymology
chemical_list: D009841:Oligonucleotides; D010446:Peptide Fragments; D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase