4b69
A. fumigatus ornithine hydroxylase (SidA) bound to ornithine
Structural highlights
FunctionSIDA_ASPFU Catalyzes the conversion of L-ornithine to N(5)-hydroxyornithine, the first step in the biosynthesis of all hydroxamate-containing siderophores, such as the secreted triacetylfusarinine C (TAFC) involved in iron uptake and the intracellular iron storage compound desferriferricrocin (DFFC). Highly specific for its substrate, only hydrolyzing l-ornithine. Has preference for NADPH over NADH, NADPH playing a role in stabilization of the C4a-hydroperoxyflavin intermediate. Essential for virulence.[1] [2] [3] [4] Publication Abstract from PubMedSidA from the human pathogen Aspergillus fumigatus catalyzes the generation of N(5)-hydroxyornithine in the biosynthesis of siderophores, a reaction essential for virulence. The crystal structures of SidA in complex with ornithine and lysine reveal the geometry of the interactions among flavin, NADP(+), and the substrate amine group that underlie the hydroxylation reaction. The structural elucidation of the enzyme in complex with arginine provides insight into the role of electrostatics and hydrogen bonding in the mechanism of oxygen activation in this family of enzymes. Structural insight into the mechanism of oxygen activation and substrate selectivity of flavin-dependent N-hydroxylating monooxygenases.,Franceschini S, Fedkenheuer M, Vogelaar NJ, Robinson HH, Sobrado P, Mattevi A Biochemistry. 2012 Sep 11;51(36):7043-5. Epub 2012 Aug 30. PMID:22928747[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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