Cooperative MetR binding in the Escherichia coli glyA control region.

We determined the relative binding affinity of the MetR protein for wild-type and mutant MetR binding sites 1 and 2 in the Escherichia coli glyA control region. The results show that MetR binding site 1 has a higher affinity for the MetR protein than binding site 2. In addition, the results suggest that binding of MetR to the glyA promoter is cooperative. Mutations that decrease the ability of MetR to bind to either site 1 or site 2 have no significant effect on MetR's ability to bend DNA.