title: Purification and characterization of the bacteriophage P4 delta protein.
abstract: The bacteriophage P4 delta protein is a transcriptional activator of the late genes of P4 as well as the late genes of its helpers, such as bacteriophage P2. delta was purified, using a variation of the MalE fusion system. With this method we purified two forms of delta: a fusion of MalE and delta and a unfused form. The fusion by itself is not active in vivo or in vitro, but the mixture of the fusion and the unfused delta is active in both. Using nitrocellulose filtration and gel mobility shift assays, we show that delta binds DNA, and using DNase I footprinting, we show that delta binds to sequences centered at approximately -55 in the two late promoters of P4 as well as the four late promoters of its helper P2. In addition, the P4 sid promoter contains a second delta binding site centered at -18.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, USA.
authors.forename: B
authors.initials: B
authors.lastname: Julien
authors.forename: R
authors.initials: R
authors.lastname: Calendar
mesh_terms: D000595:Amino Acid Sequence; D017901:Bacteriophage P2 / Q000235:genetics; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification; D003090:Coliphages / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D015967:Gene Expression Regulation, Viral; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification; D015534:Trans-Activators / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D014764:Viral Proteins
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D058619:Maltose-Binding Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014764:Viral Proteins; C094421:delta protein, Bacteriophage P4