Peptide mapping of the murine DNA methyltransferase reveals a major phosphorylation site and the start of translation.
The murine DNA methyltransferase catalyzes the transfer of methyl groups from S-adenosylmethionine to cytosines within d(CpG) dinucleotides. The enzyme is necessary for normal embryonic development and is implicated in a number of important processes, including the control of gene expression and cancer. Metabolic labeling and high pressure liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) were performed on DNA methyltransferase purified from murine erythroleukemia cells. Serine 514 was identified as a major phosphorylation site that lies in a domain required for targeting of the enzyme to the replication foci. These results present a potential mechanism for the regulation of DNA methylation. HPLC-ESI-MS peptide mapping data demonstrated that the purified murine DNA methyltransferase protein contains the N-terminal regions predicted by the recently revised 5' gene sequences (Yoder, J. A., Yen, R.-W. C., Vertino, P. M., Bestor, T. H. , and Baylin, S. B. (1996) J. Biol. Chem. 271, 31092-31097). The evidence suggests a start of translation at the first predicted methionine, with no alternate translational start sites. Our peptide mapping results provide a more detailed structural characterization of the DNA methyltransferase that will facilitate future structure/function studies.
Glickman
J F
JF
Program in Biochemistry and Molecular Biology and Department of Chemistry, University of California, Santa Barbara, California 93106, USA.
Pavlovich
J G
JG
Reich
N O
NO
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000737:chemistry* / Q000235:genetics; D006031:Glycosylation; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010766:Phosphorylation; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D012694:Serine / Q000032:analysis
D012694:Serine; D004248:DNA (Cytosine-5-)-Methyltransferases