title: High level expression of the EcoP1 modification methylase gene and characterisation of the gene product.
abstract: We have cloned the gene coding for the EcoP1 modification methylase in an expression system based on the phage lambda pL promoter and the cI857-coded thermoinducible repressor. We have used this system to purify the enzyme on the 20-30-mg scale and have examined some of its enzymatic properties. The enzyme is a tetramer of Mr 72,000 subunits and is approx. 40% alpha-helical. Experiments with the methyl donor, S-adenosyl methionine, radioactively labelled in different positions indicate that a methyl group is transferred to the enzyme during the reaction in what is most likely a covalent bond.
authors.affiliation: Department of Microbiology, University of Basel, Switzerland.
authors.forename: D P
authors.initials: DP
authors.lastname: Hornby
authors.forename: M
authors.initials: M
authors.lastname: Müller
authors.forename: T A
authors.initials: TA
authors.lastname: Bickle
mesh_terms: D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes / Q000235:genetics* / Q000302:isolation & purification; D015263:Deoxyribonucleases, Type III Site-Specific; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005796:Genes; D005798:Genes, Bacterial; D008780:Methyltransferases / Q000235:genetics* / Q000302:isolation & purification; D010957:Plasmids; D011401:Promoter Regions, Genetic; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)
chemical_list: C053885:DNA modification methylase EcoPI; D008780:Methyltransferases; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); D004262:DNA Restriction Enzymes; C030432:endodeoxyribonuclease EcoP1; D015263:Deoxyribonucleases, Type III Site-Specific