title: Inhibition of the Flavin-Dependent Monooxygenase Siderophore A (SidA) Blocks Siderophore Biosynthesis and Aspergillus fumigatus Growth.
abstract: Aspergillus fumigatus is an opportunistic fungal pathogen and the most common causative agent of fatal invasive mycoses. The flavin-dependent monooxygenase siderophore A (SidA) catalyzes the oxygen and NADPH dependent hydroxylation of l-ornithine (l-Orn) to N5-l-hydroxyornithine in the biosynthetic pathway of hydroxamate-containing siderophores in A. fumigatus. Deletion of the gene that codes for SidA has shown that it is essential in establishing infection in mice models. Here, a fluorescence polarization high-throughput assay was used to screen a 2320 compound library for inhibitors of SidA. Celastrol, a natural quinone methide, was identified as a noncompetitive inhibitor of SidA with a MIC value of 2 μM. Docking experiments suggest that celastrol binds across the NADPH and l-Orn pocket. Celastrol prevents A. fumigatus growth in blood agar. The addition of purified ferric-siderophore abolished the inhibitory effect of celastrol. Thus, celastrol inhibits A. fumigatus growth by blocking siderophore biosynthesis through SidA inhibiton.
authors: Department of Biochemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors: Julia S
authors: JS
authors: Martín Del Campo
authors: Virginia Tech Center for Drug Discovery, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors: Nancy
authors: N
authors: Vogelaar
authors: Department of Biochemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors: Karishma
authors: K
authors: Tolani
authors: Department of Biochemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors: Karina
authors: K
authors: Kizjakina
authors: Department of Biochemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors: Kim
authors: K
authors: Harich
authors: Department of Biochemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.|Virginia Tech Center for Drug Discovery, Virginia Tech , Blacksburg, Virginia 24061, United States.
authors: Pablo
authors: P
authors: Sobrado
mesh_terms: D001232:Aspergillus fumigatus / Q000254:growth & development* / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D017262:Siderophores / Q000378:metabolism*
chemical_list: D017262:Siderophores; D006899:Mixed Function Oxygenases