Cytochrome P450 monooxygenase; part of the gene cluster that mediates the biosynthesis of aurasperone B, a dimeric gamma-naphthopyrone (PubMed:31067027). The first step in the biosynthesis of aurasperone B is the production of gamma-naphthopyrone precursor YWA1 by the non-reducing polyketide synthase albA, via condensation of one acetyl-CoA starter unit with 6 malonyl-CoA units (PubMed:31067027). YWA1 is then methylated by aunE at position C-6 to yield foncesin which is further methylated at position C-8 by aunD to produce fonsecin B (Probable). A key enzyme in the biosynthetic pathway is the cytochrome P450 monooxygenase aunB which catalyzes the oxidative dimerization of fonsecin B to aurasperone B (PubMed:31067027). AunB also catalyzes the oxidative dimerization of rubrofusarin B into aurasperone A (PubMed:31067027). 2 fonsecin B + H(+) + NADPH + O2 = aurasperone B + 2 H2O + NADP(+) H(+) + NADPH + O2 + 2 rubrofusarin B = aurasperone A + 2 H2O + NADP(+) Secondary metabolite biosynthesis. Leads to the accumulation of the monomeric compounds fonsecin B and flavasperone. Belongs to the cytochrome P450 family. The sequence misses both the N-terminal and C-terminal parts. The correct gene model with the complete protein sequence could not be recovered from the submitted genomic sequence.