title: Lambda repressor inactivation: properties of purified ind- proteins in the autodigestion and RecA-mediated cleavage reactions.
abstract: Under physiological conditions, lambda repressor can be inactivated in vivo or in vitro by RecA-mediated cleavage of the polypeptide chain. The repressor protein is thought to cleave itself, with RecA acting to stimulate autodigestion. ind- repressor mutants are resistant to RecA-mediated inactivation in vivo. In this paper, we report the purification of 15 ind- repressor proteins and the behaviors of these proteins in the RecA-mediated and autodigestion cleavage reactions. None of these proteins undergoes substantial RecA-dependent cleavage. However, eight mutant proteins autodigest at the same rate as wild-type repressor, six mutants do not autodigest or autodigest slower, and one mutant autodigests faster than wild-type. We discuss these results with respect to repressor structure and RecA-binding, and suggest possible roles for the RecA protein in the cleavage reaction.
mesh_terms: D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins; D007700:Kinetics; D009154:Mutation; D009875:Operator Regions, Genetic; D011938:Rec A Recombinases / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D004279:DNA, Viral; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D011938:Rec A Recombinases