Allantofuranone Biosynthesis and Precursor-Directed Mutasynthesis of Hydroxylated Analogues

Genome mining and heterologous reconstitution of biosynthetic genes in <i>Aspergillus oryzae</i> enabled elucidation of the hitherto elusive biosynthetic route that produces allantofuranone (<b>1</b>), a bioactive natural product originally isolated from <i>Allantophomopsis lycopodina</i>. The core non-ribosomal peptide synthetase (NRPS)-like enzyme AlfA of the <i>alf</i> BGC produces polyporic acid (<b>2</b>) from phenylpyruvic acid. In subsequent reactions, compound <b>2</b> is reductively dehydrated by the bifunctional enzyme AlfC and methylated by AlfD to produce terferol (<b>6</b>). In a final step, the quinol moiety of compound <b>6</b> is oxidatively cleaved and contracted by the aromatic ring cleavage dioxygenase AlfB. Using combinatorial biosynthesis, we were able to manipulate the biosynthetic route to yield hydroxylated pathway congeners, most notably the new natural products deoxyascocorynin (<b>10</b>), hydroxyterferol (<b>11</b>), and hydroxyallantofuranone (<b>12</b>).