| | |  | | | | Record from Web of Science® | | | | | | |
| A novel type of geosmin biosynthesis in myxobacteria |
|
|
| Author(s): Dickschat JS, Bode HB, Mahmud T, Muller R, Schulz S |
| Source: JOURNAL OF ORGANIC CHEMISTRY Volume: 70 Issue: 13 Pages: 5174-5182 Published: JUN 24 2005 |
| Times Cited: 25 References: 44 |
| Abstract: The biosynthesis of geosmin (1) and (1(10)E,5E)-germacradien-11-ol (2), two volatile terpenoid compounds emitted by the myxobacteria Myxococcus xanthus and Stigmatella aurantiaca, was investigated in feeding experiments with different labeled precursors. In these experiments, the volatiles released by the cell cultures grown on agar plates were collected with a closed-loop stripping apparatus (CLSA) and analyzed by GC-MS. [H-2(10)]Leucine and [4,4,4,5,5,5-H-2(6)]dimethylacrylate were fed to wild-type strains and bkd mutant strains, which are impaired in the degradation of leucine to isovaleryl-CoA. [H-2(10)]Leucine was incorporated into 1 and 2 only by the wild-type strains via the biosynthetic pathway that involves leucine degradation and branching into the mevalonate pathway. Dimethylacrylyl-CoA (DMA-CoA) is an intermediate in the leucine degradation and in the recently discovered pathway from HMG-CoA to isovaleryl-CoA. The corresponding free acid, [4,4,4,5,5,5-H-2(6)]dimethylacrylic acid, was incorporated into 1 and 2 only by the mutants impaired in leucine degradation. [4,4,6,6,6-H-2(5)]Mevalonic acid lactone (12) was synthesized and fed to M. xanthus and S. aurantiaca wild-type strains and a double mutant strain of M. xanthus. This strain does not degrade leucine and is impaired in the reduction of 3-hydroxy-3-methylglutaryl-CoA to mevalonic acid. The mass spectral analysis of labeled 1 and 2 obtained in these feeding experiments led to a biosynthetic scheme to 1 with intermediate 2. This pathway differs from that observed in the liverwort Fossombronia pusilla and thus suggests microbial geosmin biosynthesis following a route different from that in liverworts. Our results are supported by a 1,2-hydride shift of the tertiary hydrogen atom at C-4a into the ring opposite to that in F. pusilla. |
| Document Type: Article |
| Language: English |
| Reprint Address: Schulz, S (reprint author), Tech Univ Carolo Wilhelmina Braunschweig, Inst Organ Chem, D-38106 Braunschweig, Germany |
Addresses:
1. Tech Univ Carolo Wilhelmina Braunschweig, Inst Organ Chem, D-38106 Braunschweig, Germany
2. Univ Saarland, Inst Pharmazeut Biotechnol, D-66123 Saarbrucken, Germany
3. Oregon State Univ, Corvallis, OR 97331 USA |
| Publisher: AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA |
| Subject Category: Chemistry, Organic |
| IDS Number: 938EO |
| ISSN: 0022-3263 |
| DOI: 10.1021/jo050449g |
|
| | | | | | | | | Record from Web of Science® | | | | | | | | | |