title: DNA recognition by the EcoP15I and EcoPI modification methyltransferases.
abstract: The DNA-binding properties of the EcoP15I DNA methyltransferase (M.EcoP15I; MTase) were studied using electrophoretic mobility shift assays. We show by molecular size-exclusion chromatography and dimethyl suberimidate cross-linking that M.EcoP15I is a dimer in solution. While M.EcoP15I binds approx. threefold more tightly to its recognition sequence, 5'-CAGCAG-3', than to non-specific sequences in the presence of AdoMet or its analogs, the discrimination between specific and non-specific sequences significantly increases in presence of ATP. These results suggest for the first time a role for ATP in DNA recognition by type-III restriction-modification enzymes. Furthermore, we show that although c2 EcoPI mutant MTases are defective in AdoMet binding, they are still able to bind DNA in a sequence-specific manner.
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore.
authors.forename: I
authors.initials: I
authors.lastname: Ahmad
authors.forename: V
authors.initials: V
authors.lastname: Krishnamurthy
authors.forename: D N
authors.initials: DN
authors.lastname: Rao
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D015263:Deoxyribonucleases, Type III Site-Specific / Q000737:chemistry / Q000378:metabolism*; D008780:Methyltransferases / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism*; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D009838:Oligodeoxyribonucleotides; D000255:Adenosine Triphosphate; D004247:DNA; C089712:DNA modification methylase EcoP15I; D008780:Methyltransferases; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); C030432:endodeoxyribonuclease EcoP1; D015263:Deoxyribonucleases, Type III Site-Specific