1228543-12-1Relevant articles and documents
Enzyme Cascades in Whole Cells for the Synthesis of Chiral Cyclic Amines
Hepworth, Lorna J.,France, Scott P.,Hussain, Shahed,Both, Peter,Turner, Nicholas J.,Flitsch, Sabine L.
, p. 2920 - 2925 (2017/05/31)
The increasing diversity of reactions mediated by biocatalysts has led to development of multistep in vitro enzyme cascades, taking advantage of generally compatible reaction conditions. The construction of pathways within single whole cell systems is much less explored, yet has many advantages. Herein we report the generation of a successful whole cell de novo enzyme cascade for the diastereoselective and/or enantioselective conversion of simple, linear keto acids into valuable cyclic amine products. The pathway starts with carboxylic acid reduction that triggers a transamination, imine formation, and subsequent imine reduction. Construction and optimization of the system was achieved by standard genetic manipulation and the cascade required only starting material, amine donor, and whole cell catalyst with cofactors provided internally by glucose metabolism. A panel of synthetic keto acids provided access to piperidines in high conversions (up to 93%) and enantiomeric excess (up to 93%).
An (R)-imine reductase biocatalyst for the asymmetric reduction of cyclic imines
Hussain, Shahed,Leipold, Friedemann,Man, Henry,Wells, Elizabeth,France, Scott P.,Mulholland, Keith R.,Grogan, Gideon,Turner, Nicholas J.
, p. 579 - 583 (2015/03/05)
Although the range of biocatalysts available for the synthesis of enantiomerically pure chiral amines continues to expand, few existing methods provide access to secondary amines. To address this shortcoming, we have over-expressed the gene for an (R)-imine reductase [(R)-IRED] from Streptomyces sp. GF3587 in Escherichia coli to create a recombinant whole-cell biocatalyst for the asymmetric reduction of prochiral imines. The (R)-IRED was screened against a panel of cyclic imines and two iminium ions and was shown to possess high catalytic activity and enantioselectivity. Preparative-scale synthesis of the alkaloid (R)-coniine (90 % yield; 99 % ee) from the imine precursor was performed on a gram-scale. A homology model of the enzyme active site, based on the structure of a closely related (R)-IRED from Streptomyces kanamyceticus, was constructed and used to identify potential amino acids as targets for