FIG. 4.

(A) DNA sequence alignment of the putative promoter region of the rulAB genes and the promoter of the E. coli umuDC genes. The −35 and −10 hexamers of the promoters are shaded and marked by lines. The LexA-binding consensus nucleotides (15, 72) are shown below the DNA sequence alignment and are indicated in bold. The transcriptional start site mapped for the umuDC promoter (31) is indicated by an asterisk. (B) Amino acid sequence alignment of the N termini of the UmuD and RulA proteins. The N-terminal sequence of UmuD removed after the RecA-stimulated processing of UmuD to UmuD′ (9, 43, 55) is underlined. The cleavage site between Cys24 and Gly25 and amino acids important in the cleavage reaction (Ser60 and Lys97) of UmuD (41) are shaded.