AMP-binding domain-containing enzyme; part of the gene cluster that mediates the biosynthesis of the psychoactive metabolites ibotenic acid and muscimol (PubMed:32233056). The first committed step is glutamate hydroxylation by the 2-oxoglutarate-dependent dioxygenase iboH, and the last step is decarboxylation of ibotenic acid to muscimol by the decarboxylase iboD (PubMed:32233056). The order of the intermediate reactions is somewhat ambiguous (Probable). IboA likely activates the carboxylic acid at position 5 to introduce an amide bond, and the flavin monooxygenase iboF generates the N-O bond (Probable). There are several options for the latter step (Probable). One option is that iboF directly hydroxylates the amide nitrogen formed by iboA to produce a hydroxamic acid species (Probable). Another option is that iboF hydroxylates an external N-containing compound, whose resulting N-O bond is subsequently introduced into the hydroxyglutamate scaffold (Probable). The paralogous PLP-dependent cystathionine gamma-synthase-like enzymes iboG1 and iboG2 are likely involved in substitution of the OH group at position 3 by the O-N moiety (Probable). The first cyclic intermediate is most probably tricholomic acid which is likely desaturated to ibotenic acid by the cytochrome P450 monooxygenase iboC (Probable). Secondary metabolite biosynthesis. Expression is highly induced during artificial growth in symbiosis with Populus, which is close to its natural condition. The FACS motif is required for catalytic activity and substrate specificity. Belongs to the ATP-dependent AMP-binding enzyme family.