Preliminary characterisation of an Onchocerca volvulus aspartic protease.

PCR using 1 primer specific for aspartic proteases and 1 primer annealing to the vector allowed amplification of a 377 bp fragment encoding part of an aspartic protease from an Onchocerca volvulus cDNA library. Use of this fragment as a probe allowed the isolation of a larger cDNA clone. In common with 2 other nematode aspartic proteases, the O. volvulus predicted protein has several of the general characteristics of this class of proteins, but lacks specific determinants of lysosomal localisation.