FIG. 2.

Interaction of PerR with the fur regulatory region. (A) The −35 and −10 elements of the fur promoter are underlined, and the transcriptional start sites are in bold. The Per box upstream of the −35 element is indicated. Regions of both DNA strands protected against DNase I digestion by bound PerR protein are indicated by broken double lines. (B) Primer extension mapping of the transcription start sites of the fur gene. Transcription initiates at the indicated A and G residues. (C) DNase I footprint of PerR binding to the fur operator region. The results shown are for the bottom strand. Purified PerR was added at the concentrations indicated in the presence of 10 μM Mn(II). The bold line adjacent to the G+A ladder indicates the position of the Per box, and the protected region is bracketed.