Figure 1

Serine proteases in Ae. aegypti mosquitoes are processed to generate the mature active forms of the enzymes. A) Western blot of midgut epithelium (MgEp) and food bolus protein extracts obtained from blood fed mosquitoes at 24 hr PBM using antibodies specific for AaSPVI, AaSPVII, and AaLT as previously described [13]. Each lane contains protein from 0.2 midgut equivalents obtained from pooled blood fed mosquitoes. Note that it is not possible to use a protein loading control for these two extracts because the amount of protein differs by >5-fold (MgEp versus food bolus), and moreover, the MgEp proteins are from mosquito origin and the food bolus proteins are from bovine origin. B) Amino acid sequence of the nascent polypeptide (zymogen) for the four mosquito serine proteases (AaET, AaSPVI, AaSPVII, AaLT) and bovine trypsin (BvT). The protein leader sequence was predicted by SignalP 3.0, whereas the propeptide sequence was defined as the sequence between the leader sequence C-terminus and the N-terminus of the mature form of the proteases based on the known amino acid sequence of the BvT mature form. The predicted propeptide cleavage site is shown. C) Amino acid sequence of the Mek forms of the four recombinant mosquito proteases showing the engineered EK propeptide sequence.