. 2007 Dec 5;2(12):e1271. doi: 10.1371/journal.pone.0001271

Table 1. Comparison of amino acid identities between the proteins within the toxin clusters.

Subtype	HA70	HA17	HA33	BotR	P47	NTNH		BoNT
						1^ST half	2^nd half
B1 vs bvB	96%	98%	84%	100%	-----	100%	100%	96%
bvB vs A1	98%	98%	97%	98%	-----	99%	67%	37%
	orfX3	orfX2	orfX1	BotR	P47	NTNH		BoNT
						1^ST half	2^nd half
A1 vs A2	-----	-----	-----	61%	-----	62%	90%	90%
A2 vs A3	97%	95%	97%	91%	95%	96%	93%	93%
A3 vs A4	95%	78%	88%	91%	75%	91%	94%	84%

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%.