89-82-7Relevant articles and documents
Engineering the "missing Link" in Biosynthetic (-)-Menthol Production: Bacterial Isopulegone Isomerase
Currin, Andrew,Dunstan, Mark S.,Johannissen, Linus O.,Hollywood, Katherine A.,Vinaixa, Maria,Jervis, Adrian J.,Swainston, Neil,Rattray, Nicholas J. W.,Gardiner, John M.,Kell, Douglas B.,Takano, Eriko,Toogood, Helen S.,Scrutton, Nigel S.
, p. 2012 - 2020 (2018/03/13)
The realization of a synthetic biology approach to microbial (1R,2S,5R)-(-)-menthol (1) production relies on the identification of a gene encoding an isopulegone isomerase (IPGI), the only enzyme in the Mentha piperita biosynthetic pathway as yet unidentified. We demonstrate that Δ5-3-ketosteroid isomerase (KSI) from Pseudomonas putida can act as an IPGI, producing (R)-(+)-pulegone ((R)-2) from (+)-cis-isopulegone (3). Using a robotics-driven semirational design strategy, we identified a key KSI variant encoding four active site mutations, which confer a 4.3-fold increase in activity over the wild-type enzyme. This was assisted by the generation of crystal structures of four KSI variants, combined with molecular modeling of 3 binding to identify key active site residue targets. The KSI variant was demonstrated to function efficiently within cascade biocatalytic reactions with downstream Mentha enzymes pulegone reductase and (-)-menthone:(-)-menthol reductase to generate 1 from 3. This study introduces the use of a recombinant IPGI, engineered to function efficiently within a biosynthetic pathway for the production of 1 in microorganisms.
Pinpointing a Mechanistic Switch Between Ketoreduction and “Ene” Reduction in Short-Chain Dehydrogenases/Reductases
Lygidakis, Antonios,Karuppiah, Vijaykumar,Hoeven, Robin,Ní Cheallaigh, Aisling,Leys, David,Gardiner, John M.,Toogood, Helen S.,Scrutton, Nigel S.
supporting information, p. 9596 - 9600 (2016/08/10)
Three enzymes of the Mentha essential oil biosynthetic pathway are highly homologous, namely the ketoreductases (?)-menthone:(?)-menthol reductase and (?)-menthone:(+)-neomenthol reductase, and the “ene” reductase isopiperitenone reductase. We identified a rare catalytic residue substitution in the last two, and performed comparative crystal structure analyses and residue-swapping mutagenesis to investigate whether this determines the reaction outcome. The result was a complete loss of native activity and a switch between ene reduction and ketoreduction. This suggests the importance of a catalytic glutamate vs. tyrosine residue in determining the outcome of the reduction of α,β-unsaturated alkenes, due to the substrate occupying different binding conformations, and possibly also to the relative acidities of the two residues. This simple switch in mechanism by a single amino acid substitution could potentially generate a large number of de novo ene reductases.
Asymmetric hydrogenation of heteroaromatic ketones and cyclic and acyclic enones mediated by Cu(I)-chiral diphosphine catalysts
Shimizu, Hideo,Nagano, Takuto,Sayo, Noboru,Saito, Takao,Ohshima, Takashi,Mashima, Kazushi
scheme or table, p. 3143 - 3146 (2010/03/24)
Copper(I)-catalyzed asymmetric hydrogenation of heteroaromatic ketones, cyclic and acyclic enones is reported. The choice of the chiral diphosphine ligand highly influenced enantiose-lectivity as well as chemoselectivity. Highly enantioselective hydrogenation of ortho-substituted heteroaromatic ketones was achieved using BDPP as the ligand. In the 1,2-selective hydrogenation of acylic enone, SEGPHOS gave higher enantioselectivity than BDPP. On the other hand, the bulky ligand DTBM-SEGPHOS had a 1,4-selective nature, leading to the first highly 1,4-selective and enantioselective hydrogenation of cyclic enones.
