The hexuronate metabolism in Escherichia coli is regulated by two related transcription regulators from the FadR subfamily of the GntR family, UxuR and ExuR. Both regulators were experimentally investigated in E. coli, however their DNA-binding motifs have been unknown. UxuR controls the D-glucuronate metabolism by repressing uxuAB, uidABC, gntP and its own gene uxuR. ExuR negatively controls most of the genes involved in the metabolism of both D-galacturonate and D-glucuronate, including exuT, uxaCA, uxaB, uxuAB, and exuR. Previous in silico analysis of the UxuR/ExuR regulon revealed a common DNA-binding motif with consensus AAATTGGTATACCAATTT in upstream regions of many known UxuR/ExuR-regulated genes .
Here we utilize the comparative genomics approach to reconstruct the hexuronate regulons in most Gamma-proteobacteria and demonstrated differences in the binding motifs of UxuR and ExuR [21622752