Bacterial promoter sequences. A comparison of five sequences from prokaryotic promoters reveals a recurring sequence of TATAAT centered on position −10. The −10 consensus sequence (in red) was deduced from a large number of promoter sequences. The sequences are from the (A) uvrD, (B) uncI, and (C) trp operons of E. coli, from (D) λ phage, and from (E) φX174 phage.