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The antirepressor of phage P1 Isolation and interaction with the C1 repressor of P1 and P7
Author(s) -
Riedel Hans-Dieter,
Heinrich Jochen,
Heisig Anke,
Choli Theodora,
Schuster Heinz
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81705-5
Subject(s) - open reading frame , biology , repressor , gene , genetics , microbiology and biotechnology , methionine , peptide sequence , amino acid , gene expression
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 ant 1 is required for ant 1 expression. Using appropriate ant gene‐carrying plasmids we have overproduced and purified Ant½ 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 ant 1/ ant 2, 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 Ant½ 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.