Protein sequence alignment of aspartic proteases. (a) Derived protein sequences of the 10 S. ratti aspartic protease aligned using MUSCLE . Predicted signal peptide, the mature protein starting point, and conserved N-glycosylation sites are labelled SP, MP and N-Gly, respectively. The two catalytic aspartic acid residues are indicated by (*). Cys-rich region indicated by a box. (b) Alignment of the Cys-rich region from all species using MUSCLE . Organisms are indicated after the accession numbers, as followed: Cb, Caenorhabditis briggsae; Ce, Caenorhabditis elegans; Hc, Haemonchus contortus; Na; Necator americanus; Sr, Strongyloides ratti. Figures were generated using JALVIEW .