Yeast as a tool for characterizing mono-ADP-ribosyltransferase toxins.
The emergence of bacterial antibiotic resistance poses a significant challenge in the pursuit of novel therapeutics, making new strategies for drug discovery imperative. We have developed a yeast growth-defect phenotypic screen to help solve this current dilemma. This approach facilitates the identification and characterization of a new diphtheria toxin (DT) group, ADP-ribosyltransferase toxins from pathogenic bacteria. In addition, this assay utilizes Saccharomyces cerevisiae, a reliable model for bacterial toxin expression, to streamline the identification and characterization of new inhibitors against this group of bacterial toxins that may be useful for antimicrobial therapies. We show that a mutant of the elongation factor 2 target protein in yeast, G701R, confers resistance to all DT group toxins and recovers the growth-defect phenotype in yeast. We also demonstrate the ability of a potent small-molecule toxin inhibitor, 1,8-naphthalimide (NAP), to alleviate the growth defect caused by toxin expression in yeast. Moreover, we determined the crystal structure of the NAP inhibitor-toxin complex at near-atomic resolution to provide insight into the inhibitory mechanism. Finally, the NAP inhibitor shows therapeutic protective effects against toxin invasion of mammalian cells, including human lung cells.
Turgeon
Zachari
Z
Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.
White
Dawn
D
Jørgensen
René
R
Visschedyk
Danielle
D
Fieldhouse
Robert J
RJ
Mangroo
Dev
D
Merrill
A Rod
AR
D036002:ADP Ribose Transferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D001681:Biological Assay / Q000379:methods*; D002460:Cell Line; D004167:Diphtheria Toxin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
D004167:Diphtheria Toxin; D036002:ADP Ribose Transferases