FIG 5.

AirR specifically binds the crt promoter region. The electrophoretic mobility of the labeled promoter fragment alone is shown in the first lane. Increasing amounts of AirR (1.0, 1.6, 2.1, and 4.2 μM) were incubated with labeled crt promoter probe. −, absence of competitor DNA; +, addition of 100-fold excess competitor DNA. BSA (1.6 μM) and a nonspecific unlabeled probe (an internal fragment of sspA) were used as nonspecific binding controls. For each reaction, 20 fmol of biotin-labeled crt promoter probe was included. All the reaction mixtures totaled 20 μl.