Oligopeptidase B from Trypanosoma brucei, a new member of an emerging subgroup of serine oligopeptidases.

Abstract

Trypanosoma brucei contains a soluble serine oligopeptidase (OP-Tb) that is released into the host bloodstream during infection, where it has been postulated to participate in the pathogenesis of African trypanosomiasis. Here, we report the identification of a single copy gene encoding the T. brucei oligopeptidase and a homologue from the related trypanosomatid pathogen Leishmania major. The enzymes encoded by these genes belong to an emerging subgroup of the prolyl oligopeptidase family of serine hydrolases, referred to as oligopeptidase B. The trypanosomatid oligopeptidases share 70% amino acid sequence identity with oligopeptidase B from the intracellular pathogen Trypanosoma cruzi, which has a demonstrated role in mammalian host cell signaling and invasion. OP-Tb exhibited no activity toward the prolyl oligopeptidase substrate H-Gly-Pro-7-amido-4-methylcoumarin. Instead, it had activity toward substrates of trypsin-like enzymes, particularly those that have basic amino acids in both P(1) and P(2) (e.g. benzyloxycarbonyl-Arg-Arg-7-amido-4-methylcoumarin k(cat)/K(m) = 529 s(-1) microM(-1)). The activity of OP-Tb was enhanced by reducing agents and by polyamines, suggesting that these agents may act as in vivo regulators of OP-Tb activity. This study provides the basis of the characterization of a novel subgroup of serine oligopeptidases from kinetoplastid protozoa with potential roles in pathogenesis.

• Authors: R E Morty, J D Lonsdale-Eccles, J Morehead, E V Caler, R Mentele, E A Auerswald, T H Coetzer, N W Andrews, B A Burleigh
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 274 Issue 37 Pg. 26149-56 (Sep 10 1999) ISSN: 0021-9258 [Print] United States
• PMID: 10473566 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Serine Proteinase Inhibitors
• Serine Endopeptidases
• oligopeptidase B

Topics

• Amino Acid Sequence
• Animals
• Hydrogen-Ion Concentration
• Molecular Sequence Data
• Sequence Homology, Amino Acid
• Serine Endopeptidases (chemistry, genetics, metabolism)
• Serine Proteinase Inhibitors (pharmacology)
• Substrate Specificity
• Trypanosoma brucei brucei (enzymology)