"The enzyme L-ornithine N5-oxygenase catalyzes the hydroxylation of L-ornithine (L-Orn), which represents an early step in the biosynthesis of the peptidic moiety of the fluorescent siderophore pyoverdin in Pseudomonas aeruginosa."

"the pvdA mutant obtained by gene disruption also disclosed no pyoverdin synthesis, lacked L-Orn N5-oxygenase activity, was complemented by the cloned pvdA gene, and produced pyoverdin at wild-type levels when fed with the biosynthetic precursor L-N5-OH-Orn."

"Formation of the iron-chelating hydroxamate functional group in pyoverdine requires the enzyme PvdA, a flavin-dependent monooxygenase that catalyzes the N(5) hydroxylation of l-ornithine."

"The enzyme is specific for NADPH and flavin adenine dinucleotide (FAD(+)) as cofactors, as it cannot utilize NADH and flavin mononucleotide."

"PvdA belongs to the class B flavoprotein monooxygenases, which catalyze the oxidation of substrates using NADPH as the electron donor and molecular oxygen."

"PvdA has the two expected Rossmann-like dinucleotide-binding domains for FAD and NADPH and also a substrate-binding domain, with the active site at the interface between the three domains."

"The L-ornithine N(delta)-oxygenase PvdA catalyses the N(delta)-hydroxylation of L-ornithine in many Pseudomonas spp., and thus provides an essential enzymic function in the biogenesis of the pyoverdine siderophore."

"The inferred topological model resembled a eukaryotic reverse signal-anchor (type III) protein, with a single N-terminal domain anchored to the inner membrane, and the bulk of the protein spanning the cytosol."

"generate P.aeruginosa strains producing fluorescent fusions with PvdA, one of the initial enzymes in the biosynthetic pathway of PVDI in the cytoplasm"

"Cellular fractionation indicated that a substantial amount of PvdA-YFP was located in the membrane fraction."

"Structural analysis of the pyoverdine produced by the closely related P. putida KT2440 showed that this strain produces an already characterised pyoverdine, but different from P. entomophila, and no evidence was found for the production of a second siderophore."

"Expression from the respective promoters is stimulated by iron limitation albeit to varying degrees."

"Deletion of pvdRT-opmQ leads to reduced amounts of pyoverdine in the medium and decreased growth under iron limitation."

"Mutants defective in arginine biosynthesis show reduced production and release of the siderophore pyoverdine and altered expression of certain pyoverdine-related genes, resulting in higher sensitivity to iron limitation."

"Q88GC8 is the KT2440 ortholog of the pyoverdine biosynthetic ornithine hydroxylase PvdA"

"The direct process annotation is pyoverdine biosynthetic process rather than intracellular iron ion homeostasis"

"Cytoplasm is the conservative cellular component call for KT2440 PvdA"

"The UniProt accession **Q88GC8** corresponds to **pvdA / PP_3796** from *Pseudomonas putida* strain KT2440 and is functionally described as an **L-ornithine N5-monooxygenase (ornithine hydroxylase)**"

"**pvdA encodes the enzyme catalyzing the N5-hydroxylation of L-ornithine** to produce **N5-hydroxyornithine**, which is subsequently **formylated by PvdF** to yield **N5-formyl-N5-hydroxyornithine (L-fOHOrn)**."

"PvdA belongs to the **flavin-dependent N-hydroxylating monooxygenase / Class B flavin monooxygenase** family."

"dependence on **FAD** as a flavin cofactor and **molecular oxygen** as the oxygen donor, proceeding through **C4a-peroxy/hydroperoxyflavin** intermediates that effect oxygen transfer to the substrate amine"

"**substrate binding triggers O2 addition but not flavin reduction**, consistent with gating of the oxidative half-reaction by L-ornithine binding"

"PvdA functions in the **cytoplasmic phase** of **pyoverdine siderophore biosynthesis**, supplying a modified amino acid building block needed by the **NRPS assembly line**."

"Pyoverdine biosynthesis initiates in the **cytoplasm**"

"**PvdA physically interacts with all four pyoverdine NRPSs**"

"This is an early, committed tailoring step in pyoverdine assembly."

"**pvdA** and **pvdD** expression increased in these mutants, while **pvdE** (an inner-membrane transporter needed for immature pyoverdine handling) decreased"

"The gene **pvdA** (UniProt **Q88GC8**, ordered locus **PP_3796**) of *Pseudomonas putida* KT2440 encodes **L-ornithine N⁵-oxygenase (PvdA)**"

"Direct biochemistry is from orthologs, not Q88GC8 itself."

"Formyltransferase identity in KT2440."