FIGURE 4.

Binding sequences of OxyR2_5CA-C206D within the prx2 promoter region. A, a 260-bp DNA fragment of the upstream region of P_prx2 was radioactively labeled and then used as probe DNA. The radiolabeled probe DNA (25 nm) was incubated with increasing amounts of the purified OxyR2_5CA-C206D as indicated and then digested with DNase I. The regions protected by OxyR2_5CA-C206D are indicated by open boxes, whereas the nucleotides showing enhanced cleavage are indicated by a black box. Lanes C, T, A, and G, nucleotide sequencing ladder of P_prx2. Nucleotide numbers shown are relative to the transcription start site of P_prx2. B, the sequences for binding of OxyR2_5CA-C206D are indicated below the P_prx2 sequences as diagonal-filled boxes. The sequences for binding of oxidized OxyR2 (white box) and reduced OxyR2 (gray boxes) determined previously (11) are presented above the P_prx2 sequences. The nucleotides showing enhanced cleavage by binding of OxyR2_5CA-C206D and the reduced OxyR2 are indicated as black boxes. The transcription start site of P_prx2 identified previously (11) is indicated by a bent arrow, and the positions of the putative −10 and −35 regions are underlined. The ATG translation initiation codon and the putative ribosome-binding site (SD) are also indicated in boldface type.