title: Trypanosoma brucei brucei oligopeptidase B null mutants display increased prolyl oligopeptidase-like activity.
abstract: African trypanosomosis is a parasitic disease in man and animals caused by protozoan parasites of the genus Trypanosoma. Nagana, the cattle form of the disease, is caused by Trypanosoma congolense, Trypanosoma vivax and Trypanosoma brucei brucei. An option for developing vaccines and chemotherapeutic agents against trypanosomosis is to target pathogenic factors released by the parasite during infection, namely an "anti-disease" approach. One such pathogenic factor is oligopeptidase B (TbOPB), a trypanosome peptidase that hydrolyses Arg/Lys containing peptides smaller than 30 amino acid residues and is suspected to be involved in the hormonal deregulation associated with the disease. To better understand the role TbOPB plays in parasite physiology and host pathogenesis, oligopeptidase B null mutant parasites (Δopb) were generated in the T. b. brucei Lister 427 strain. Δopb Trypanosoma brucei parasites grew at a significantly faster rate in vitro, and were as virulent as wild type strains during infection in mice. Immunohistopatholgy of infected mouse testes revealed Δopb parasites in extra vascular regions showing that TbOPB is not involved in assisting T. brucei parasites to cross microvascular endothelial cells. Gelatine gel analysis of Δopb null mutants showed an increase in discrete cysteine peptidase activities when compared to wild type strains. Enzymatic activity assays were carried out to identify how closely related oligopeptidases are affected by TbOPB gene deletion. A significant increase of T. brucei prolyl oligopeptidase (TbPOP) activity was observed, but no concomitant increase in TbPOP protein levels, suggesting that a POP-like enzyme might compensate for a loss in OPB activity in Δopb null mutants.
authors: School of Biochemistry, Genetics and Microbiology, University of KwaZulu-Natal (Pietermaritzburg campus), Private Bag X01, Scottsville 3209, South Africa.
authors: Richard T
authors: RT
authors: Kangethe
authors: Alain F V
authors: AF
authors: Boulangé
authors: Virginie
authors: V
authors: Coustou
authors: Théo
authors: T
authors: Baltz
authors: Theresa H T
authors: TH
authors: Coetzer
mesh_terms: D000818:Animals; D002199:Capillary Permeability; D004195:Disease Models, Animal; D004789:Enzyme Activation; D005260:Female; D017353:Gene Deletion; D017125:Genes, Protozoan; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D000085822:Prolyl Oligopeptidases; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D013737:Testis / Q000469:parasitology / Q000473:pathology; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D014353:Trypanosomiasis, African / Q000469:parasitology; D014774:Virulence
chemical_list: D015800:Protozoan Proteins; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases; C090703:oligopeptidase B