title: 'Pseudo' domains in phage-encoded DNA methyltransferases.
abstract: 5-Cytosine-DNA-methyltransferases, which are found in many organisms ranging from bacteriophages to mammals, transfer a methyl group from S-adenosylmethionine to the carbon-5 of a cytosine residue in specific DNA target sequences. Some phage-encoded methyltransferases methylate more than one sequence: these enzymes contain several independent target-recognizing domains each responsible for recognizing a different site. The amino-acid sequences of these multispecific methyltransferases reveal that some enzymes in addition carry domains that do not contribute to the enzymes' methylation potential, but strongly resemble previously identified target-recognizing domains. Here we show that introducing defined amino-acid alterations into these inactive domains endows these enzymes with additional methylation specificities. Gel retardation analysis demonstrates that these novel methylation specificities correlate with the acquisition of additional DNA-binding potential of the proteins.
authors.affiliation: Max-Planck-Institut für molekulare Genetik, Berlin, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Lange
authors.forename: A
authors.initials: A
authors.lastname: Jugel
authors.forename: J
authors.initials: J
authors.lastname: Walter
authors.forename: M
authors.initials: M
authors.lastname: Noyer-Weidner
authors.forename: T A
authors.initials: TA
authors.lastname: Trautner
mesh_terms: D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000201:enzymology; D001665:Binding Sites; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D015257:DNA-Cytosine Methylases / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D004268:DNA-Binding Proteins; D015257:DNA-Cytosine Methylases; D004248:DNA (Cytosine-5-)-Methyltransferases