Oligopeptidase B, a missing enzyme in mammals and a potential drug target for trypanosomatid diseases

Oligopeptidases B (OPB) belong to the S9 prolyl oligopeptidase family and are expressed in prokaryotes, some eukaryotes and in some higher plants. OPB is not found in any of the mammalian genomes available to date. Evidences indicate that OPB participates in the infections caused by trypanosomatids Trypanosoma cruzi, Leishmania spp. and Trypanosoma brucei spp and therefore it is considered an important virulence factor. Trypanosomatids from the genera Leishmania and Trypanosoma also present other OPB, named OPB2. A more accurate investigation of trypanosomatid OPB sequences brought attention to what could be a third OPB sequence (OPB3). This review aims to discuss biochemical, structural, phylogenetic and functional properties of OPB and its potential as target for the development of drugs against Chagas disease, leishmaniasis and African trypanosomiasis.