Characterization of a cDNA encoding a cathepsin L-like protein of Rhodniusprolixus

The interaction of Rhodnius prolixus digestive enzymes with Trypanosoma cru zi could be important for parasite survival. We report herein the complete sequence of the messenger of a cathepsin L-like molecule (RpCat). The cDNA has 5'- and 3'- end UTRs and a methionine codon that corresponds likely to a translation initiation codon. In the deduced amino acid sequence, a regio n corresponding to an ERFININ domain, diagnostic of L-cathepsins, and a pos sible pro-peptide cleavage site were observed. At the C-terminus, a nine-am ino acid sequence, almost identical to a secretion signal of human cathepsi n L was found. RpCat messenger was expressed in intestines of R. prolixus a dults, and from 1st to 4th but not in 5th instar nymph stages. In a similar ity analysis, RpCat was grouped with L cathepsins forming a clear group sep arate of the B cathepsins.