FIG. 7.

Gel shift analysis of the binding of GntR to the gntT and gntKU operators and effects of mutations in the GntR-binding elements of gntKU on its binding. Gel shift analysis was performed as described in Materials and Methods. DNA fragments from pGNTT-LAC4 (A), pGNTK-LAC (B and D), pGNTK-LACMR1 (C), pGNTK-LACMR2 (C), and pGNTK-LACMR12 (D) were used. pGNTK-LACMR1, pGNTK-LACMR2, and PGNTK-LACMR12 have mutations in the R1, R2, and both R1 and R2 sequences, respectively, of the gntKU promoter-operator region. The shifted bands at the top and in the middle as well as free DNA at the bottom are indicated by arrowheads.