Recovery of operator DNA binding activity from denatured lactose repressor

Lactose repressor monomer subunits, prepared with sodium dodecyl sulfate, have been renatured-reassociated to yield tetrameric repressors active in binding to operator DNA. The majority of moleculesin renatured repressor populations have operator binding properties indistinguishable from the stock, undenatured repressors from which they were prepared. Renaturation of a mixture of monomers from wild-type (Q) and a tight binding repressor yields a population of active repressors containing molecules with operator binding characteristics intermediate to those of the "parental" repressor types.