Figure 1. Characterization of longipain cDNA.

(A) Nucleotide and predicted amino acid sequence of the longipain cDNA. The nucleotide sequence is numbered on the left and the deduced amino acid sequence is numbered on the right. The stop codon is indicated by an asterisk. Blue and green lettering indicate the signal peptide and N-glycosylation sites, respectively. Red highlighting indicates conserved motifs that form the catalytic triad of the active site in Clan CA cysteine proteases, including Cys-117 (red lettering), His-287 (red lettering), and Asp-307 (red lettering). Yellow highlighting marks the S₂ pocket of cathepsin. The occluding loop of cathepsin B-like protease is shown boxed. The dotted box indicates the nine-amino-acid peptide loop suggesting mannose-6-phosphate-independent trafficking. (B) Alignment of the amino acid sequences of longipain and cathepsin B-like protein from Araneus ventricosus (GenBank accession number AAP59456), the amphioxus Branchiostoma belcheri tsingtaunesehuman (AAQ83887), the kissing bug, Triatoma sordida (AAT48984), and Homo sapiens (AAH10240). Identical residues are marked with an asterisk. Gaps, marked with hyphens, have been introduced for better alignment.