Indole diterpene prenyltransferase; part of the gene cluster that mediates the biosynthesis of the prenylated pyrroloindoline diketopiperazine acetylaszonalenin (PubMed:19001367). The first step in the pathway is the formation of (R)-benzodiazepinedione by condensation of tryptophan and anthranilic acid catalyzed by the non-ribosomal peptide synthetase anaPS (PubMed:19001367). The prenyltransferase anaPT then converts (R)-benzodiazepinedione to aszonalenin in the presence of dimethylallyl diphosphate (DMAPP) via C3-prenylation (PubMed:19001367, PubMed:19421461, PubMed:20165805, PubMed:24014429, PubMed:26294262). The last step in the biosynthesis of acetylaszonalenin via acetylation of aszonalenin at position N1 catalyzed by anaAT (PubMed:19001367, PubMed:20165805). Alkaloid biosynthesis. Belongs to the tryptophan dimethylallyltransferase family.