title: Amino-terminal fragments of Escherichia coli lac repressor bind to DNA.
abstract: The N-terminal fragments (residues 1-51 and 1-59) obtained by selective tryptic cleavage of native lac repressor retain the ability to bind DNA. These fragments (headpieces) are monomeric and form complexes which resemble those of tetrameric repressor with non-operator DNA. But, they do not show the high specificity of repressor for operator sequences. The DNA binding has been demonstrated by filter-binding assay as well as in solution using absorption, circular dichroism, and fluorescence measurements.
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D002942:Circular Dichroism; D004269:DNA, Bacterial / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005374:Filtration; D005809:Genes, Regulator; D007785:Lactose / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011067:Poly dA-dT / Q000378:metabolism; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D010446:Peptide Fragments; D011067:Poly dA-dT; D007785:Lactose