Alignment of QseC sequences from enterobacteria with a putative sensor histidine kinase in V. cholerae. Using E. coli K-12 QseC as the input, sequence comparisons were performed using an identity and similarity threshold of 83% and the BLOSUM62 scoring matrix. E. coli K-12 QseC (GenBank accession no. YP_491218.1), E. coli O157:H7 QseC (GenBank accession no. AAG58160.1) (98% identity, 99% similarity), and Salmonella enterica QseC (GenBank accession no. WP_023185439.1) (80% identity, 89% similarity) are compared. The putative sensor histidine kinase in V. cholerae O1 classical strain O395 (GenBank accession no. ABQ19142.1) (29% identity, 47% similarity) was also included. The predicted transmembrane helices TM1 and TM2, the conserved His residue accepting a phosphoryl group (arrow) within the His kinase A domain, and the C-terminal histone ATPase c domain (HATPase C) are indicated.