Biosynthesis of the diterpene verrucosan-2beta-ol in the phototrophic eubacterium Chloroflexus aurantiacus. A retrobiosynthetic NMR study.
The biosynthesis of verrucosan-2beta-ol in the green phototrophic eubacterium Chloroflexus aurantiacus was investigated by in vivo incorporation of singly or doubly 13C-labeled acetate. The 13C labeling of the isolated diterpene was analyzed by one- and two-dimensional NMR spectroscopy. The 13C-labeling patterns of verrucosan-2beta-ol were compared with the labeling patterns of intermediary metabolites (acetyl-CoA, pyruvate, and glyceraldehyde 3-phosphate) which were deduced from amino acids and nucleosides by retrobiosynthetic analysis. The results show that verrucosan-2beta-ol is synthesized via mevalonate and not via the deoxyxylulose pathway, which was discovered recently in some eubacteria, algae, and plants. A scheme for the formation of the unusual tetracyclic ring system is offered. The cyclization process is initiated by the solvolysis of pyrophosphate from geranyllinaloyl pyrophosphate and the mechanism involves a Wagner-Meerwein rearrangement, a 1,5-hydride shift, and a cyclopropylcarbinyl to cyclopropylcarbinyl rearrangement.
Rieder
C
C
Department of Organic Chemistry and Biochemistry, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany.
Strauss
G
G
Fuchs
G
G
Arigoni
D
D
Bacher
A
A
Eisenreich
W
W
D000105:Acetyl Coenzyme A / Q000378:metabolism; D019414:Chlorobi / Q000378:metabolism*; D004224:Diterpenes / Q000378:metabolism*; D005986:Glyceraldehyde 3-Phosphate / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008798:Mevalonic Acid / Q000378:metabolism; D008956:Models, Chemical; D019289:Pyruvic Acid / Q000378:metabolism; D014996:Xylulose / Q000031:analogs & derivatives / Q000378:metabolism
D004224:Diterpenes; D005986:Glyceraldehyde 3-Phosphate; D014996:Xylulose; C029724:1-deoxy-2-pentulose; C113568:verrucosan-2-ol; D000105:Acetyl Coenzyme A; D019289:Pyruvic Acid; D008798:Mevalonic Acid