title: Enzymatic synthesis of natural (+)-aristolochene from a non-natural substrate.
abstract: The sesquiterpene cyclase aristolochene synthase from Penicillium roquefortii (PR-AS) has evolved to catalyse with high specificity (92%) the conversion of farnesyl diphosphate (FDP) to the bicyclic hydrocarbon (+)-aristolochene, the natural precursor of several fungal toxins. Here we report that PR-AS converts the unnatural FDP isomer 7-methylene farnesyl diphosphate to (+)-aristolochene via the intermediate 7-methylene germacrene A. Within the confined space of the enzyme's active site, PR-AS stabilises the reactive conformers of germacrene A and 7-methylene germacrene A, respectively, which are protonated by the same active site acid (most likely HOPPi) to yield the shared natural bicyclic intermediate eudesmane cation, from which (+)-aristolochene is then generated.
authors.affiliation: School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK. AllemannRK@cardiff.ac.uk.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Faraldos
authors.affiliation: School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK. AllemannRK@cardiff.ac.uk.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Grundy
authors.affiliation: School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK. AllemannRK@cardiff.ac.uk.
authors.forename: Oscar
authors.initials: O
authors.lastname: Cascon
authors.affiliation: School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK. AllemannRK@cardiff.ac.uk.
authors.forename: Stefano
authors.initials: S
authors.lastname: Leoni
authors.affiliation: School of Biochemistry, Faculty of Biomedical Sciences & Centre for Computational Chemistry, School of Chemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK.
authors.forename: Marc W
authors.identifier: http://orcid.org/0000-0002-8060-3359
authors.initials: MW
authors.lastname: van der Kamp
authors.affiliation: School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK. AllemannRK@cardiff.ac.uk.
authors.forename: Rudolf K
authors.identifier: http://orcid.org/0000-0002-1323-8830
authors.initials: RK
authors.lastname: Allemann