Fig. 2

Phylogenetic trees of cathepsin B of 19 organisms estimated with the MP method (a) and the predicted 3-dimensional structure of T. spiralis cathepsin B (b, c). b The predicted 3-dimensional structure of TsCB contains 7 α-helixes (red) and 13 β-strand (blue). c Functional domain carrying catalytic reactive sites consisted of Gln124, Cys155, Asn305, and Gly328 residues, formed a functional domain. The TsCB active sites are highlighted in red