Purification of the LysR family regulator, ClcR, and its interaction with the Pseudomonas putida clcABD chlorocatechol operon promoter

Gel filtration and amino acid sequencing of the regulator of LYSR family, ClcR, reveals that ClcR is a dimer with its active fractions having molecular mass of 74 plus or minus 12 kDa. DNAse I foot printing analysis of ClcR helps determine its binding sites. Comparison of the binding of ClcR and the chlorocatechol operon promoter CatR, of Pseudomonas putida ClcABD regulators to their promoters showed that unlike CatR, ClcR attaches to activation binding site and repression binding site (RBS) target regions without any effector. Further analysis indicates the presence of a second element between the ATG start site and ClcR-ABD RBS region.