TY - JOUR
T1 - The need for enzymatic steering in abietic acid biosynthesis
T2 - Gas-phase chemical dynamics simulations of carbocation rearrangements on a bifurcating potential energy surface
AU - Siebert, Matthew R.
AU - Zhang, Jiaxu
AU - Addepalli, Srirangam V.
AU - Tantillo, Dean J.
AU - Hase, William L.
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2011/6/1
Y1 - 2011/6/1
N2 - Abietic acid, a constituent of pine resin, is naturally derived from abietadiene - a process that requires four enzymes: one (abietadiene synthase) for conversion of the acyclic, achiral geranylgeranyl diphosphate to the polycyclic, chiral abietadiene (a complex process involving the copalyl diphosphate intermediate) and then three to oxidize a single methyl group of abietadiene to the corresponding carboxylic acid. In previous work (Nature Chem.2009, 1, 384), electronic structure calculations on carbocation rearrangements leading to abietadienyl cation revealed an interesting potential energy surface with a bifurcating reaction pathway (two transition-state structures connected directly with no intervening minimum), which links two products - one natural and one not yet isolated from Nature. Herein we describe direct dynamics simulations of the key step in the formation of abietadiene (in the gas phase and in the absence of the enzyme). The simulations reveal that abietadiene synthase must intervene in order to produce abietadiene selectively, in essence steering this reaction to avoid the generation of byproducts with different molecular architectures.
AB - Abietic acid, a constituent of pine resin, is naturally derived from abietadiene - a process that requires four enzymes: one (abietadiene synthase) for conversion of the acyclic, achiral geranylgeranyl diphosphate to the polycyclic, chiral abietadiene (a complex process involving the copalyl diphosphate intermediate) and then three to oxidize a single methyl group of abietadiene to the corresponding carboxylic acid. In previous work (Nature Chem.2009, 1, 384), electronic structure calculations on carbocation rearrangements leading to abietadienyl cation revealed an interesting potential energy surface with a bifurcating reaction pathway (two transition-state structures connected directly with no intervening minimum), which links two products - one natural and one not yet isolated from Nature. Herein we describe direct dynamics simulations of the key step in the formation of abietadiene (in the gas phase and in the absence of the enzyme). The simulations reveal that abietadiene synthase must intervene in order to produce abietadiene selectively, in essence steering this reaction to avoid the generation of byproducts with different molecular architectures.
UR - http://www.scopus.com/inward/record.url?scp=79957762465&partnerID=8YFLogxK
U2 - 10.1021/ja201730y
DO - 10.1021/ja201730y
M3 - Article
C2 - 21548620
AN - SCOPUS:79957762465
VL - 133
SP - 8335
EP - 8343
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 21
ER -