Protein sequence alignment between S. ratti ASP-2A and the principal templates used in its modelling. Alignment of ASP-2A with the principal templates used in its modelling, human pepsin in complex with pepstatin (PDB code 1pso; ) and mouse renin bound to the decapeptide inhibitor CH-66 (1smr; ). Shading indicates the degree of sequence similarity at each position. For the Cys-rich region, Cys residues are numbered and secondary structure predicted (using PSIPRED ; red indicates α-helices) on lines below the alignment. Where only a single one of these two templates was used, the excluded template region is shown in light grey text. Boxed regions of ASP-2A indicate portions modelled using additional templates, Candida albicans aspartic proteinase 3 (PDB code 2h6t; ) for residues 247-249 and human renin (PDB code 1hrn; ) for residues 308-311 (see Materials and Methods). The figure was produced with Jalview .