Artemisinin biosynthesis in growing plants of Artemisia annua. A 13CO2 study.
Artemisinin from Artemisia annua has become one of the most important drugs for malaria therapy. Its biosynthesis proceeds via amorpha-4,11-diene, but it is still unknown whether the isoprenoid precursors units are obtained by the mevalonate pathway or the more recently discovered non-mevalonate pathway. In order to address that question, a plant of A. annua was grown in an atmosphere containing 700 ppm of 13CO2 for 100 min. Following a chase period of 10 days, artemisinin was isolated and analyzed by 13C NMR spectroscopy. The isotopologue pattern shows that artemisinin was predominantly biosynthesized from (E,E)-farnesyl diphosphate (FPP) whose central isoprenoid unit had been obtained via the non-mevalonate pathway. The isotopologue data confirm the previously proposed mechanisms for the cyclization of (E,E)-FPP to amorphadiene and its oxidative conversion to artemisinin. They also support deprotonation of a terminal allyl cation intermediate as the final step in the enzymatic conversion of FPP to amorphadiene and show that either of the two methyl groups can undergo deprotonation.
Schramek
Nicholas
N
Lehrstuhl für Biochemie, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching, Germany.
Wang
Huahong
H
Römisch-Margl
Werner
W
Keil
Birgit
B
Radykewicz
Tanja
T
Winzenhörlein
Bernhard
B
Beerhues
Ludger
L
Bacher
Adelbert
A
Rohdich
Felix
F
Gershenzon
Jonathan
J
Liu
Benye
B
Eisenreich
Wolfgang
W
D000962:Antimalarials / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D031172:Artemisia annua / Q000737:chemistry / Q000378:metabolism*; D037621:Artemisinins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D053898:Biosynthetic Pathways; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D008288:Malaria / Q000188:drug therapy; D008798:Mevalonic Acid / Q000378:metabolism*; D015394:Molecular Structure; D008517:Phytotherapy; D000081223:Polycyclic Sesquiterpenes; D011106:Polyisoprenyl Phosphates / Q000737:chemistry / Q000378:metabolism*; D012717:Sesquiterpenes / Q000737:chemistry / Q000378:metabolism*
D000962:Antimalarials; D037621:Artemisinins; D002247:Carbon Isotopes; D000081223:Polycyclic Sesquiterpenes; D011106:Polyisoprenyl Phosphates; D012717:Sesquiterpenes; C515348:amorpha-4,11-diene; D002245:Carbon Dioxide; C004808:farnesyl pyrophosphate; C031327:artemisinin; D008798:Mevalonic Acid