ABSTRACT
The parasitic protists of the Trypanosoma genus infect humans and domestic mammals, causing severe mortality and huge economic losses. The most threatening trypanosomiasis is Chagas disease, affecting up to 12 million people in the Americas. We report a way to selectively kill Trypanosoma by blocking glycosomal/peroxisomal import that depends on the PEX14-PEX5 protein-protein interaction. We developed small molecules that efficiently disrupt the PEX14-PEX5 interaction. This results in mislocalization of glycosomal enzymes, causing metabolic catastrophe, and it kills the parasite. High-resolution x-ray structures and nuclear magnetic resonance data enabled the efficient design of inhibitors with trypanocidal activities comparable to approved medications. These results identify PEX14 as an "Achilles' heel" of the Trypanosoma suitable for the development of new therapies against trypanosomiases and provide the structural basis for their development.
Subject(s)
Membrane Proteins/antagonists & inhibitors , Protozoan Proteins/antagonists & inhibitors , Small Molecule Libraries/pharmacology , Trypanocidal Agents/pharmacology , Trypanosoma brucei brucei/drug effects , Animals , Chagas Disease/drug therapy , Drug Design , Humans , Membrane Proteins/chemistry , Microbodies/drug effects , Microbodies/metabolism , Nuclear Magnetic Resonance, Biomolecular , Peroxisome-Targeting Signal 1 Receptor , Peroxisomes/drug effects , Peroxisomes/metabolism , Protein Domains , Protein Transport/drug effects , Protozoan Proteins/chemistry , Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors , Receptors, Cytoplasmic and Nuclear/chemistry , Receptors, Cytoplasmic and Nuclear/metabolism , Small Molecule Libraries/chemistry , Small Molecule Libraries/therapeutic use , Trypanocidal Agents/chemistry , Trypanocidal Agents/therapeutic use , Trypanosomiasis, African/drug therapyABSTRACT
BACKGROUND: The aim of the current study was to investigate whether the Basidiomycetes fungus Lentinula edodes can biosynthesize Se-methyl-seleno-l-cysteine, a seleno-amino acid with strong anticancer activity, and to optimize the culture conditions for its biosynthesis. We hypothesize that preparations obtained from Se-methyl-seleno-l-cysteine-enriched mycelia from this medicinal mushroom would possess stronger cancer-preventive properties than current preparations. RESULTS: By optimizing the concentration of selenium in the culture medium, we increased the mycelial concentration of Se-methyl-seleno-l-cysteine from essentially non-detectable levels to 120 µg/g dry weight. Significantly elevated levels of this amino acid also correlated with significant (twofold) inhibition of mycelial growth. Increases in the concentration of mycelial Se-methyl-seleno-l-cysteine appeared to be highly correlated with the enhanced biosynthesis of selenomethionine and total selenium content in mycelium. CONCLUSIONS: We have demonstrated that in L. edodes, enhanced biosynthesis of this non-protein amino acid eliminates excess selenium.
