期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1971
卷号：68
期号：8
页码：1891-1895
DOI：10.1073/pnas.68.8.1891
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The repressor of the galactose operon of Escherichia coli has been partially purified and identified as a protein. Induction of a lysogen in which {lambda} was linked to the bacterial galR and lysine genes resulted in a large increase in the production of the gal repressor. Single-step purification by affinity chromatography, using the ligand p-aminophenyl-{beta}-D-thiogalactoside linked to beaded agarose, provided a convenient method of separating the gal repressor from other DNA-binding proteins. Binding of gal repressor to {lambda}pgal[32P]DNA was studied by assay of binding to a nitrocellulose filter. Interaction between gal repressor and {lambda}pgal DNA showed a high degree of specificity; the dissociation constant of the complex was estimated to be 1.0 x 10-12 M. Unlabeled {lambda}pgal DNA competed for binding to gal repressor, but {lambda}DNA and {lambda}h80dlac DNA did not. Fucose and galactose, which function as inducers of the galactose operon in vivo, produced one-half maximal inhibition of gal repressor-{lambda}pgal DNA binding at concentrations of 5 x 10-5 M.
