Phylogenetic analysis of the dinB, yafN, yafO and yafP operon within the E. coli species. (A) Schematic representation of the four-gene operon as found in E. coli K-12 MG1655 and E. fergusonii and the two-gene operon as found in E. coli CFT073. In the latter case, dinB and yafP genes are fused together and overlap by four nucleotides, i.e., ATGA (B) Structure of the dinB operon in genomes of the strains from ECOR collection representative of the E. coli strain phylogeny. The strain phylogenic tree was reconstructed from MLST data (20). Numbers at nodes represent bootstrap values superior to 70%. Strains labelled in red or blue possess either the four-genes operons or the two-genes operons, respectively. The four strains labelled in black correspond to strains whose operons were not analyzed for following reasons: ECOR 9 strain has an insertion sequence in the dinB genes leading to a non-functional operon, and ECOR 5, 64, 47 strains for which no PCR amplification was obtained suggesting that dinB operon region could be rearranged or deleted.