Mapping of the cytochrome c553 gene and hydA TSSs. The TSS of the cytochrome c553 gene was mapped using WT H. pylori RNA. Using the cyto_c553_PE primer, which lies within the cytochrome c553 coding region, first-strand cDNA was synthesized. Only a single band was detected, indicating a single TSS for this gene as shown in panel A. Panel B shows the cytochrome c553 gene promoter region, with the core promoter elements indicated. The TSS of the hydA promoter was mapped in a similar manner using the hydA_PE primer. A single band was detected for this promoter, which indicated a single TSS for hydA as shown in panel C. The hydA promoter region with the core promoter elements indicated is shown in panel D. The TSS is indicated by “+1”; the −10 and −35 promoter elements are underlined and labeled accordingly. The translational start codon is given in bold. Data shown are representative of a minimum of two experimental replicates.