Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Kempe, K.; Higashi, Y.; Frick, S.; Sabarna, K.; Kutchan, T. M.;RNAi suppression of the morphine biosynthetic gene salAT and evidence of association of pathway enzymesPhytochemistry70579-589(2009)DOI: 10.1016/j.phytochem.2009.03.002
Papaver somniferum L. was transformed with an RNAi construct designed to reduce transcript levels of the gene encoding the morphine biosynthetic enzyme, salutaridinol 7-O-acetyltransferase (SalAT). RNA interference of salAT led to accumulation of the intermediate compounds, salutaridine and salutaridinol, in a ratio ranging from 2:1 to 56:1. Along the morphine biosynthetic pathway, salutaridine is stereospecifically reduced by salutaridine reductase (SalR) to salutaridinol, which is subsequently acetylated by SalAT. SalAT transcript was shown by quantitative PCR to be diminished, while salR transcript levels remained unaffected. Yeast two-hybrid and co-immunoprecipitation analyses indicated an interaction between SalR and SalAT, which suggested the occurrence of an enzyme complex and provided an explanation for the unexpected accumulation of salutaridine. Decreased concentrations of thebaine and codeine in latex were also observed, while the morphine levels remained constant compared to concentrations found in untransformed control plants.
Publikation
Frick, S.; Ounaroon, A.; Kutchan, T. M.;Combinatorial biochemistry in plants: the case of O-methyltransferasesPhytochemistry561-4(2001)DOI: 10.1016/S0031-9422(00)00378-2
Combinatorial chemistry is common place today in chemical synthesis. Virtually thousands of derivatives of a molecule can be achieved by automated systems. The use of biological systems to exploit combinatorial chemistry (combinatorial biochemistry) now has multiple examples in the polyketide field. The modular functional domain structure of polyketide synthases have been recombined through genetic engineering into unnatural constellations in heterologous hosts in order to produce polyketide structures not yet discovered in nature. We present herein an example for a potential type of combinatorial biochemistry in alkaloidal systems using various combinations of Thalictrum tuberosum (meadow rue) O-methyltransferase subunits that result in heterodimeric enzymes with substrate specificities that differ from those of the homodimeric native enzymes.