FIG 3.

Zur recognizes Zur box sequences of target genes. To assess direct binding of Zur to predicted Zur boxes upstream of putative Zur-regulated genes, electrophoretic mobility shift assays were performed using purified Zur incubated with radiolabeled target DNA. Zur boxes from select Zur-regulated genes were assessed. For gene labels, 3411 is A1S_3411, 3412 is A1S_3412, and 3103 is A1S_3103. (A) Purified Zur incubated with either the Zur box sequence or negative-control sequence (Neg. DNA), which is DNA immediately adjacent to the Zur box sequence of the respective gene. Each DNA sequence was incubated in the presence or absence of particular Zur proteins, as designated in the bottom row by a plus or minus sign. (B) Purified Zur incubated with Zur box sequence in the presence or absence of an unlabeled specific competitor DNA (SC; Zur box sequence from panel A) as designated in the bottom row by a plus or minus sign. (C) Purified Zur incubated with Zur box sequence in the presence of the unlabeled specific competitor DNA (SC) or a nonspecific competitor DNA (NS; negative-control sequence used in panel A) as designated in the bottom row by a plus or minus sign.