Comparison of amino acid identities between the proteins within the toxin clusters.

Percent amino acid identities between the different BoNT subtypes are shown for each of the proteins within the toxin clusters. Amino acid identity among the A1 and B1/bvB cluster proteins (HA70, HA17, HA33, BotR, and NTNH) ranges from 83–100%. Comparison of the BoNTs in A1 versus B1 strains show only 37% amino acid identity; the NTNH comparisons for BoNT/A1 vs B1 show that the first half of the protein is similar while the second half is divergent. The amino acid identity within the toxin cluster found among the BoNT/A2-A4 subtypes ranges from 74–98%. Within the three subtypes the most similar proteins appear to be NTNH, BotR, and orfX3 (92–98%), while the orfX1, orfX2, p47, and the BoNT similarities range from 74–93%.