title: Interaction of the bacteriophage P22 Arc repressor with operator DNA.
abstract: Are repressor binds to a single, partially symmetric, 21 base-pair operator site that is centered between the -10 and -35 regions of the Pant promoter. Protection and interference experiments show that Arc makes contacts with the operator on one side of the DNA helix. Although Arc is a small protein (53 residues/subunit), it makes contacts that are farther from the center of the operator than those made by many larger repressors. These extended contacts include the phosphate groups at the ends of the 21 base-pair site. Under standard conditions (pH 7.5, 100 mM-KCl, 3 mM-MgCl2, 22 degrees C) half-maximal operator binding is observed at an Arc concentration of 2.5 X 10(-9) M and the protein-DNA complex is very stable (t1/2 approximately equal to 80 min).
authors: Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
authors: A K
authors: AK
authors: Vershon
authors: S M
authors: SM
authors: Liao
authors: W R
authors: WR
authors: McClure
authors: R T
authors: RT
authors: Sauer
mesh_terms: D004279:DNA, Viral / Q000378:metabolism*; D005786:Gene Expression Regulation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D012097:Repressor Proteins / Q000378:metabolism*; D012483:Salmonella Phages / Q000235:genetics*; D013696:Temperature; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000378:metabolism*; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D004279:DNA, Viral; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins