An alignment of Spo0A homologs. The predicted amino acid sequences of Spo0A from B. subtilis 168, B. anthracis Ames, C. acetobutylicum ATCC 824, C. botulinum ATCC 3502, Cellulosilyticum lentocellum DSM 5427 and Epulopiscium sp. type B were aligned using CLUSTALΩ. The conserved phosphorylation site (highlighted in yellow), the conformational switch (in green) and the DNA recognition helix (light blue) are found in all homologs. The connector segment (outlined in black) links the upstream phospho-acceptor and downstream effector domains. Shaded bars below the effector domain indicate the helix-turn-helix (HTH) DNA binding motif.