Nucleotide and deduced amino acid sequence of R . ( B .) microplus aspartic proteinase cDNA. The predicted 20-aa signal peptide is underlined. The conserved residues involved in catalysis are in rectangles. The regions identified by LC-MS/MS are shaded. The cysteine residues involved in dissulfide bond formation are in black. The GenBank accession number for this sequence is FJ655904.