Mechanism-of-action determination of GMP synthase inhibitors and target validation in Candida albicans and Aspergillus fumigatus.
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.
Rodriguez-Suarez
Roberto
R
Center of Fungal Genetics, Merck Frosst Canada, Montreal, Quebec H2X 3Y8, Canada.
Xu
Deming
D
Veillette
Karynn
K
Davison
John
J
Sillaots
Susan
S
Kauffman
Sarah
S
Hu
Wenqi
W
Bowman
Joel
J
Martel
Nick
N
Trosok
Steve
S
Wang
Hao
H
Zhang
Li
L
Huang
Li-Yin
LY
Li
Yang
Y
Rahkhoodaee
Fariba
F
Ransom
Tara
T
Gauvin
Daniel
D
Douglas
Cameron
C
Youngman
Phil
P
Becker
Jeff
J
Jiang
Bo
B
Roemer
Terry
T
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
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