Dipeptidyl peptidase 3, a novel protease from Leishmania braziliensis

PLoS One. 2018 Jan 5;13(1):e0190618. doi: 10.1371/journal.pone.0190618. eCollection 2018.

Abstract

The increase of leishmaniasis cases worldwide and the emergence of Leishmania strains resistant to current treatments make necessary to find new therapeutic targets. Proteases are appealing drug targets because they play pivotal roles in facilitating parasite survival and promoting pathogenesis. Enzymes belonging to the dipeptidyl peptidase 3 (DPP3) group have been described in different organisms such as mammals, insects and yeast, in which these enzymes have been involved in both protein turnover and protection against oxidative damage. The aim of this work was to characterize the structure and function of the Leishmania braziliensis DPP3 (LbDPP3) protein as the first step to elucidate its suitability as a potential drug target. Sequence alignment showed 43% of identity between LbDPP3 and its human orthologous (hDPP3) enzyme. Although the modeled protein adopted a globally conserved three-dimensional (3D) structure, structural differences were found in the vicinity of the active site and the substrate binding-cleft. In addition, the Leishmania protein was expressed as a soluble recombinant protein and its kinetics parameters were determined using the z-Arginine-Arginine-AMC substrate. The LbDPP3 activity was maximal at pH values between 8.0-8.5. Interestingly, classical enzyme inhibitors such as the tynorphin and its derivative peptide IVYPW were found to actively inhibit the LbDPP3 activity. Moreover, these DPP3 inhibitors showed a detrimental effect upon parasite survival, decreasing the viability of promastigotes by up to 29%. Finally, it was observed that LbDPP3 was equally expressed along the in vitro differentiation from promastigotes to axenic amastigotes. In conclusion, these findings suggest that the L. brazileinsis DPP3 could be a promising drug target.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cloning, Molecular
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / chemistry
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / genetics
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / metabolism*
  • Humans
  • Leishmania braziliensis / enzymology*
  • Sequence Homology, Amino Acid

Substances

  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases

Grants and funding

This work was supported by the Pontificia Universidad Javeriana (Colombia) Research Project ID PPTA 5586 “Characterization of proteic factors associated to the messengers of the protein α-tubulin of Leishmania braziliensis” granted to CJP. JRD was supported by the “Young researchers and innovators” program (645/2015-2016 and 706/2016-2017) from the Administrative Department of Science Technology and Innovation COLCIENCIAS.