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| Content Provider | Springer Nature Link |
|---|---|
| Author | Bringmann, Gerhard Irmer, Andreas |
| Copyright Year | 2008 |
| Abstract | Phenylanthraquinones belong to the quite rare class of fully unsymmetric biaryls, consisting of two different molecular portions, an anthraquinone part, chrysophanol, and a phenyl part, 2,4-dihydroxy-6-methoxyacetophenone, linked together by phenol-oxidative coupling. The biosynthesis of these two moieties, from eight and four acetate units, respectively, bears some unique features: Chrysophanol is the first example of an acetogenic natural product that is, in an organism-specific manner, formed via more than one folding mode: In eukaryotes, like, e.g., in fungi, in higher plants, and in insects, it is formed via folding mode F, while in prokaryotes it originates through mode S. It has, more recently, even been found to be synthesized by a third pathway, which we have named mode S′. It is thus the first example of biosynthetic convergence in polyketide biosynthesis. The monocyclic “southern” portion of the molecule, which is much simpler (arising from only four acetate units and without decarboxylation), unexpectedly does not show the anticipated randomization of the C$_{2}$-labeling in the aromatic ring, but has clearly localized C$_{2}$ units, excluding any symmetric intermediate like, e.g., 2,4,6-trihydroxyacetophenone. This is confirmed by competitive feeding experiments with specifically $^{13}$C$_{2}$-labeled acetophenones, showing the O-methylation to be the decisive symmetry-preventing step, which hints at a close collaboration of the participating enzymes. The results make knipholone an instructive example of structure, function, and evolution of polyketide synthases and O-methyltransferases, and their cooperation. |
| Starting Page | 499 |
| Ending Page | 511 |
| Page Count | 13 |
| File Format | |
| ISSN | 15687767 |
| Journal | Phytochemistry Reviews |
| Volume Number | 7 |
| Issue Number | 3 |
| e-ISSN | 1572980X |
| Language | English |
| Publisher | Springer Netherlands |
| Publisher Date | 2008-02-22 |
| Publisher Place | Dordrecht |
| Access Restriction | One Nation One Subscription (ONOS) |
| Subject Keyword | Polyketides Chrysophanol Knipholone Biosynthesis Feeding experiments Polyketide synthase O-Methyltransferase Chemistry/Food Science Organic Chemistry Biochemistry Plant Genetics & Genomics Plant Sciences |
| Content Type | Text |
| Resource Type | Article |
| Subject | Plant Science Biotechnology |
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