title: Overexpression, purification and characterization of the Escherichia coli MelR transcription activator protein.
abstract: The gene encoding Escherichia coli MelR protein has been cloned in the expression vector pJLA502. MelR has been overexpressed, substantially purified and shown to bind to DNA fragments carrying the melAB promoter. A truncated version of the melR gene, encoding the C-terminal half of MelR, was also cloned into pJLA502; the protein product of this truncated gene binds to the melAB promoter but was not overproduced. A number of amino acid substitutions were made in the recognition helices of two putative helix-turn-helix motifs in the C-terminal part of MelR, and the effects of these mutations on MelR-dependent transcription initiation at the melAB promoter have been measured.
authors.affiliation: School of Biochemistry, University of Birmingham, U.K.
authors.forename: R
authors.initials: R
authors.lastname: Caswell
authors.forename: J
authors.initials: J
authors.lastname: Williams
authors.forename: A
authors.initials: A
authors.lastname: Lyddiatt
authors.forename: S
authors.initials: S
authors.lastname: Busby
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D015870:Gene Expression / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C077649:MelR protein, E coli; D015534:Trans-Activators