title: The primary diterpene synthase products of Picea abies levopimaradiene/abietadiene synthase (PaLAS) are epimers of a thermally unstable diterpenol.
abstract: The levopimaradiene/abietadiene synthase from Norway spruce (Picea abies; PaLAS) has previously been reported to produce a mixture of four diterpene hydrocarbons when incubated with geranylgeranyl diphosphate as the substrate: levopimaradiene, abietadiene, neoabietadiene, and palustradiene. However, variability in the assay products observed by GC-MS of this and orthologous conifer diterpene synthases over the past 15 years suggested that these diterpenes may not be the initial enzyme assay products but are rather the products of dehydration of an unstable alcohol. We have identified epimers of the thermally unstable allylic tertiary alcohol 13-hydroxy-8(14)-abietene as the products of PaLAS. The identification of these compounds, not previously described in conifers, as the initial products of PaLAS has considerable implications for our understanding of the complexity of the biosynthetic pathway of the structurally diverse diterpene resin acids of conifer defense.
authors.affiliation: Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Keeling
authors.forename: Lina L
authors.initials: LL
authors.lastname: Madilao
authors.forename: Philipp
authors.initials: P
authors.lastname: Zerbe
authors.forename: Harpreet K
authors.initials: HK
authors.lastname: Dullat
authors.forename: Jörg
authors.initials: J
authors.lastname: Bohlmann
mesh_terms: D045784:Abietanes / Q000737:chemistry; D000438:Alcohols / Q000737:chemistry; D019883:Alkyl and Aryl Transferases / Q000378:metabolism*; D002853:Chromatography, Liquid / Q000379:methods; D004926:Escherichia coli / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006838:Hydrocarbons / Q000737:chemistry; D007700:Kinetics; D013058:Mass Spectrometry / Q000379:methods; D028222:Picea / Q000201:enzymology*; D010936:Plant Extracts / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D013237:Stereoisomerism; D013696:Temperature; D013729:Terpenes / Q000737:chemistry*
chemical_list: D045784:Abietanes; D000438:Alcohols; D006838:Hydrocarbons; D010936:Plant Extracts; D011994:Recombinant Proteins; D013729:Terpenes; C101761:abieta-7(8),13(14)-diene; D019883:Alkyl and Aryl Transferases; C434663:levopimaradiene synthase