title: Distinct mechanisms for spiro-carbon formation reveal biosynthetic pathway crosstalk.
abstract: Spirotryprostatins, an indole alkaloid class of nonribosomal peptides isolated from Aspergillus fumigatus, are known for their antimitotic activity in tumor cells. Because spirotryprostatins and many other chemically complex spiro-carbon-bearing natural products exhibit useful biological activities, identifying and understanding the mechanism of spiro-carbon biosynthesis is of great interest. Here we report a detailed study of spiro-ring formation in spirotryprostatins from tryprostatins derived from the fumitremorgin biosynthetic pathway, using reactants and products prepared with engineered yeast and fungal strains. Unexpectedly, FqzB, an FAD-dependent monooxygenase from the unrelated fumiquinazoline biosynthetic pathway, catalyzed spiro-carbon formation in spirotryprostatin A via an epoxidation route. Furthermore, FtmG, a cytochrome P450 from the fumitremorgin biosynthetic pathway, was determined to catalyze the spiro-ring formation in spirotryprostatin B. Our results highlight the versatile role of oxygenating enzymes in the biosynthesis of structurally complex natural products and indicate that cross-talk of different biosynthetic pathways allows product diversification in natural product biosynthesis.
authors.affiliation: Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Tsunematsu
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Ishikawa
authors.forename: Daigo
authors.initials: D
authors.lastname: Wakana
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Goda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Noguchi
authors.forename: Hisao
authors.initials: H
authors.lastname: Moriya
authors.forename: Kinya
authors.identifier: 0000000294270081
authors.initials: K
authors.lastname: Hotta
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology; D001232:Aspergillus fumigatus / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D004271:DNA, Fungal / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D008958:Models, Molecular; D015394:Molecular Structure; D010879:Piperazines / Q000737:chemistry* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D013141:Spiro Compounds / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; D004271:DNA, Fungal; D010879:Piperazines; D013141:Spiro Compounds; C478300:spirotryprostatin A