Fig. 5.

Sequence alignment of partial Stn and each of the A subunits of CT and LT. Amino acid sequences of Stn, CT (CT-A) and LT (LT-A) were derived from S. typhimurium strain Q1, Vibrio cholerae El Tor strain N16961, and enterotoxigenic E. coli strain H10407, respectively (Chopra et al., 1994; Heidelberg et al., 2000; Crossman et al., 2010). Asterisks represent the identical amino acid residues in Stn compared with those of CT and LT. Box and italic letters indicate the conserved motif and catalytic amino acid for ADP-ribosyltransferase of CT and LT (Laing et al., 2011).