FIG. 1.

Alignment of amino acid sequences of C2II from Clostridium botulinum strains (C) 2300, (C) 203U28, (C) 468, and (D) 1873. Three characters are used to mark conserved positions: an asterisk indicates positions which have a single, fully conserved residue; a colon indicates that one of the “strong” STA, NEQK, NHQK, NDEQ, QHRK, MILV, MILF, HY, and FYW groups is fully conserved; a period indicates that one of the “weaker” CSA, ATV, SAG, STNK, STPA, SGND, SNDEQK, NDEQHK, NEQHRK, FVLIM, and HFY groups is fully conserved. These are all the positively scoring groups that occur in the Gonnet Pam 250 matrix. The strong and weak groups are defined by a score of >0.5 and a score of <0.5, respectively. The alignment was done by ClustalX (21).