title: The antirepressor of phage P1. Isolation and interaction with the C1 repressor of P1 and P7.
abstract: Two antirepressor proteins, Ant1 and Ant2, of molecular weight 42 and 32 kDa, respectively, are encoded by P1 as a single open reading frame, with the smaller protein initiating at an in-frame start codon. Another open reading frame, icd, 5' upstream of and overlapping ant1 is required for ant1 expression. Using appropriate ant gene-carrying plasmids we have overproduced and purified Ant1/2 in the form of a protein complex and Ant2 as a single protein. Sequence analysis confirmed the N-terminal amino acids predicted from the DNA sequence of ant1/ant2, except that the N-terminal methionine is missing in the Ant2 protein. Under appropriate conditions the C1 repressors of phages P1 and P7 specifically co-precipitate with the Ant1/2 complex but not with Ant2 protein alone. The results suggest that the antirepressor may exert its C1-inactivating function by a direct protein-protein interaction.
authors.affiliation: Max-Planck-Institut für Molekulare Genetik, Berlin, Germany.
authors.forename: H D
authors.initials: HD
authors.lastname: Riedel
authors.forename: J
authors.initials: J
authors.lastname: Heinrich
authors.forename: A
authors.initials: A
authors.lastname: Heisig
authors.forename: T
authors.initials: T
authors.lastname: Choli
authors.forename: H
authors.initials: H
authors.lastname: Schuster
mesh_terms: D000595:Amino Acid Sequence; D017101:Bacteriophage P1 / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003090:Coliphages / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009876:Operon; D010957:Plasmids; D012097:Repressor Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D015183:Restriction Mapping; D014764:Viral Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: C081160:Ant protein, Enterobacteria phage P22; D012097:Repressor Proteins; D014764:Viral Proteins