Constitutive Promoters (Type-B Spacers) (Leftward transcription).

Among the total of 1,075 RpoD holoenzyme-binding sites, 181 are located within type-B spacers upstream of left-side genes and downstream of right-side genes, indicating that these promoters direct leftward transcription. The genes and operons under the control of these 181 promoters were estimated, of which 16 represent putative internal promoters. Descriptions and symbols are as in Table 1. A total of 15 genes encoding transcription factors are indicated by star symbols (*). The essential genes listed in the PEC database are underlined within the operons. The promoter sequence with complete match with the canonical promoter (see Fig. 4) is shown in bold and italic while the promoter sequence with 5-out of-6 match is shown in bold. The spacers including H-NS binding sites are marked as HNS in the spacer column. Total number of genes under the control of these 181 promoters were 290 (1.80 gene per promoter). Among the total of 181 RpoD holoenyme-binding sites, 39 (24%) overlap with the H-NS-binding sites.