... FEBSCharacterization of HbpR binding by site-directedmutagenesis of its DNA -binding site and by deletion of the effector domainDavid Tropel1* and Jan R. van der Meer1,21 Process of Environmental ... the HbpR–DNA binding interactions were investigatedby site-directed mutagenesis of the operator region and by DNA -binding assays using purified HbpR. Mutations that disrupted the twofold sym-metry ... operator types 2, 4, 5, 7, 72 and 45 (Fig. 4).Interestingly, this showed that a loss of binding affinitycorrelated to a deterioration of binding contacts inonly those regions with new mutations,...