title: Mechanism-of-action determination of GMP synthase inhibitors and target validation in Candida albicans and Aspergillus fumigatus.
abstract: Mechanism-of-action (MOA) studies of bioactive compounds are fundamental to drug discovery. However, in vitro studies alone may not recapitulate a compound's MOA in whole cells. Here, we apply a chemogenomics approach in Candida albicans to evaluate compounds affecting purine metabolism. They include the IMP dehydrogenase inhibitors mycophenolic acid and mizoribine and the previously reported GMP synthase inhibitors acivicin and 6-diazo-5-oxo-L-norleucine (DON). We report important aspects of their whole-cell activity, including their primary target, off-target activity, and drug metabolism. Further, we describe ECC1385, an inhibitor of GMP synthase, and provide biochemical and genetic evidence supporting its MOA to be distinct from acivicin or DON. Importantly, GMP synthase activity is conditionally essential in C. albicans and Aspergillus fumigatus and is required for virulence of both pathogens, thus constituting an unexpected antifungal target.
authors.affiliation: Center of Fungal Genetics, Merck Frosst Canada, Montreal, Quebec H2X 3Y8, Canada.
authors.forename: Roberto
authors.initials: R
authors.lastname: Rodriguez-Suarez
authors.forename: Deming
authors.initials: D
authors.lastname: Xu
authors.forename: Karynn
authors.initials: K
authors.lastname: Veillette
authors.forename: John
authors.initials: J
authors.lastname: Davison
authors.forename: Susan
authors.initials: S
authors.lastname: Sillaots
authors.forename: Sarah
authors.initials: S
authors.lastname: Kauffman
authors.forename: Wenqi
authors.initials: W
authors.lastname: Hu
authors.forename: Joel
authors.initials: J
authors.lastname: Bowman
authors.forename: Nick
authors.initials: N
authors.lastname: Martel
authors.forename: Steve
authors.initials: S
authors.lastname: Trosok
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Li-Yin
authors.initials: LY
authors.lastname: Huang
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Fariba
authors.initials: F
authors.lastname: Rahkhoodaee
authors.forename: Tara
authors.initials: T
authors.lastname: Ransom
authors.forename: Daniel
authors.initials: D
authors.lastname: Gauvin
authors.forename: Cameron
authors.initials: C
authors.lastname: Douglas
authors.forename: Phil
authors.initials: P
authors.lastname: Youngman
authors.forename: Jeff
authors.initials: J
authors.lastname: Becker
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.forename: Terry
authors.initials: T
authors.lastname: Roemer
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D001232:Aspergillus fumigatus / Q000187:drug effects* / Q000201:enzymology; D002176:Candida albicans / Q000187:drug effects* / Q000201:enzymology; D019731:Carbon-Nitrogen Ligases / Q000037:antagonists & inhibitors*; D003980:Diazooxonorleucine / Q000494:pharmacology; D025141:Drug Resistance, Fungal; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007168:IMP Dehydrogenase / Q000037:antagonists & inhibitors; D007555:Isoxazoles / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009173:Mycophenolic Acid / Q000494:pharmacology; D011687:Purines / Q000378:metabolism; D012263:Ribonucleosides / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D004791:Enzyme Inhibitors; D007555:Isoxazoles; D011687:Purines; D012263:Ribonucleosides; D003980:Diazooxonorleucine; C010052:mizoribine; D007168:IMP Dehydrogenase; D019731:Carbon-Nitrogen Ligases; C020828:GMP synthase (glutamine-hydrolyzing); D009173:Mycophenolic Acid; C006303:acivicin; C030985:purine