Leishmania (Viannia) braziliensis: insights on subcellular distribution and biochemical properties of heparin-binding proteins

Abstract

SUMMARYLeishmaniasis is a vector-borne disease and an important public health issue. Glycosaminoglycan ligands inLeishmaniaparasites are potential targets for new strategies to control this disease. We report the subcellular distribution of heparin-binding proteins (HBPs) inLeishmania (Viannia) braziliensisand specific biochemical characteristics ofL. (V.) braziliensisHBPs. Promastigotes were fractionated, and flagella and membrane samples were applied to HiTrap Heparin affinity chromatography columns. Heparin-bound fractions from flagella and membrane samples were designated HBP Ffand HBP Mf, respectively. Fraction HBP Ffpresented a higher concentration of HBPs relative to HBP Mf, and SDS-PAGE analyses showed 2 major protein bands in both fractions (65 and 55 kDa). The 65 kDa band showed gelatinolytic activity and was sensitive to inhibition by 1,10-phenanthroline. The localization of HBPs on the promastigote surfaces was confirmed using surface plasmon resonance (SPR) biosensor analysis by binding the parasites to a heparin-coated sensor chip; that was inhibited in a dose-dependent manner by pre-incubating the parasites with variable concentrations of heparin, thus indicating distinct heparin-binding capacities for the two fractions. In conclusion, protein fractions isolated from either the flagella or membranes ofL. (V.) braziliensispromastigotes have characteristics of metallo-proteinases and are able to bind to glycosaminoglycans.