FIG. 2.

Gel mobility shift analysis of the interaction of protein extracts from the wild-type strain ISP794 with different fragments of the norA promoter and the effect of unlabeled DNA. The radiolabeled fragment (arrow) was incubated with increasing amounts of protein extracts. The labeled fragments used in these experiments are L4-R1 (315 bp) (A), L2-R2 (153 bp) (B), L2-R3 (87 bp) (C), L1-R2 (60 bp) (D), and L5-R2 (39 bp) (E). The protein(s) binds to the tested fragment and retards its mobility (a different gel was used for each fragment). An unlabeled fragment of 350 bp amplified by PCR from a Klebsiella oxytoca promoter and an unlabeled fragment of the tested fragment serve as specificity control (NSPE DNA and SPE DNA, respectively). Protein and DNA concentrations and ratios of unlabeled fragments to labeled fragments used in this assay are indicated in the tables above the figures.