Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6494141 | Metabolic Engineering | 2018 | 38 Pages |
Abstract
2,4-dihydroxybutyrate (DHB) is a precursor for the chemical synthesis of the methionine analogue 2-hydroxy-4-(methylthio)butyrate. Since no annotated metabolic pathway exists for its microbial production from sugar, we have conceived a two-step synthetic metabolic pathway which converts the natural amino acid homoserine to DHB. The pathway proceeds through the homoserine transaminase-catalyzed deamination of homoserine to obtain 2-oxo-4-hydroxybutyrate (OHB), and continues with the reduction of OHB to DHB, which is catalyzed by an OHB reductase enzyme. We identified homoserine transaminase and OHB reductase activity in several candidate enzymes which act on sterically cognate substrates, and improved OHB reductase activity of lactate dehydrogenase A of Lactococcus lactis by structure-based enzyme engineering. Fed-batch cultivation of a homoserine-overproducing Escherichia coli strain which expressed homoserine transaminase and OHB reductase enzymes resulted in the production of 5.3Â g/L DHB at a yield of 0.1Â g/g.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Bioengineering
Authors
Thomas Walther, Florence Calvayrac, Yoann Malbert, Ceren Alkim, Clémentine Dressaire, Hélène Cordier, Jean Marie François,