title: Cooperative and salt-resistant binding of lexA protein to non-operator DNA.
abstract: The interaction of the lexA repressor of E. coli with poly[d(A-T)] has been studied by circular dichroism. The binding induces an about 2-fold increase of the circular dichroism intensity at 263 nm, pointing out a conformational change of the nucleic acid. The observed spectral changes are very similar to those observed for the binding of the lac repressor to poly[d(A-T)] and natural DNA. At elevated ionic strength the binding isotherms do show a pronounced sigmoidal shape indicating a cooperative mode of binding.
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D002942:Circular Dichroism; D004269:DNA, Bacterial / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D009994:Osmolar Concentration; D011067:Poly dA-dT / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D012697:Serine Endopeptidases; D014157:Transcription Factors / Q000378:metabolism*; D000099160:LexA Repressor Protein
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011067:Poly dA-dT; D012097:Repressor Proteins; D012697:Serine Endopeptidases; D014157:Transcription Factors; D000099160:LexA Repressor Protein