Involved in the biosynthesis of furanonaphthoquinone I (FNQ I). Catalyzes C- and O-prenylations of different phenolic substrates. With flaviolin as substrate, catalyzes the formation of a carbon-carbon-bond between C-3 (rather than C-1) of geranyl diphosphate and C-3 of flaviolin. With 1,3-dihydroxynaphthalene and 4-hydroxybenzoate as substrates, catalyzes O-prenylations. (2E)-geranyl diphosphate + flaviolin = 3-linalylflaviolin + diphosphate Does not require magnesium or any other divalent metal ions for activity. kcat is 0.013 min(-1) for flaviolin. kcat is 0.14 min(-1) for 4-hydroxybenzoate. Monomer. Mutant still produces endophenazine A, but does not produce FNQ I. Belongs to the aromatic prenyltransferase family.