Fig. 10.

Gel retardation analyses of AraR binding to the araD and abnE promoter regions. (A) All lanes contained about 0.12 ng of a radioactively labeled 42-bp DNA fragment containing the araD promoter. Lane 1 contained 100 μg of crude extract from E. coli cells carrying only the vector (pET11d). Lane 2 contained no extract. Lanes 3 to 8 contained different concentrations of crude extracts of E. coli cells producing AraR. (B) All lanes contained about 0.12 ng of a radioactively labeled DNA fragment containing the abnE promoter. Lane 1 contained 100 μg of crude extract from cells carrying only the vector (pET11d). Lane 2 contained no extract. Lanes 3 to 6 contained different concentrations of crude extracts of E. coli cells producing AraR. Lane 7 contained an unrelated 32-bp fragment containing a 14-bp inverted repeat (the GlcUA operator). (C) Binding of AraR to the abnE promoter in the presence of various sugars. Each lane contained 0.12 ng of labeled DNA, crude extract of E. coli cells producing AraR (100 ng/μl), and the following sugar at 0.2 mM: arabinoheptaose (A₇) (lane 1), arabinohexaose (A₆) (lane 2), arabinopentaose (A₅) (lane 3), arabinotetraose (A₄) (lane 4), arabinotriose (A₃) (lane 5), arabinobiose (A₂) (lane 6), arabinose (A₁) (lane 7), or glucose (Glu) (lane 8).