Comparative alignment of complete amino acid sequences of E. chaffeensis (ECH), E. coli (ECOLI) and C. trachomatis (CTR) major σ subunit to show sequence homology. The GenBank accession numbers for these sequences are NC007799, NC000913 and NC012687, respectively. The numbers of the amino acids of the corresponding genus are indicated at the far right. Asterisks denote amino acid homology; dots denote amino acid mismatch. Dashes are gaps introduced into the sequence to improve the alignment. The shaded amino acid sequence represents the putative binding site of the E. coli anti-σ70 monoclonal antibody, 2G10 .