Construction of a synthetic metabolic pathway for biosynthesis of the non-natural methionine precursor 2,4-dihydroxybutyric acid

Thomas Walther (1, 2) , Christopher Topham (1) , Romain Irague (2) , Clément Auriol (2) , Audrey Baylac (2) , Hélène Cordier (2) , Clémentine Dressaire (1, 2) , Luce Lozano-Huguet (1) , Nathalie Tarrat (1, 3) , Nelly Martineau (1, 4) , Marion Stodel (2) , Yannick Malbert (1, 2) , Marc Maestracci (4) , Robert Huet (4) , Isabelle André (1, 2) , Magali Remaud Simeon (1, 2) , Jean Marie François (1, 2)

1 LISBP - Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés
2 TWB - Toulouse White Biotechnology
3 CEMES-SINanO - Surfaces, Interfaces et Nano-Objets
4 Adisseo France SAS

2,4-Dihydroxybutyric acid (DHB) is a molecule with considerable potential as a versatile chemical synthon. Notably, it may serve as a precursor for chemical synthesis of the methionine analogue 2-hydroxy-4-(methylthio) butyrate, thus, targeting a considerable market in animal nutrition. However, no natural metabolic pathway exists for the biosynthesis of DHB. Here we have therefore conceived a three-step metabolic pathway for the synthesis of DHB starting from the natural metabolite malate. The pathway employs previously unreported malate kinase, malate semialdehyde dehydrogenase and malate semialdehyde reductase activities. The kinase and semialdehyde dehydrogenase activities were obtained by rational design based on structural and mechanistic knowledge of candidate enzymes acting on sterically cognate substrates. Malate semialdehyde reductase activity was identified from an initial screening of several natural enzymes, and was further improved by rational design. The pathway was expressed in a minimally engineered Escherichia coli strain and produces 1.8 g l(-1) DHB with a molar yield of 0.15.

Mots clés: isobutyric acid; plasmid; metabolic pathway; animal feeding; aspartyl kinase

Mots clés: voie métabolique; acide butyrique; plasmide; aspartate kinase; alimentation animale; malate; synthon; escherichia coli

Domaines: Génie des procédés

Thomas Walther, Christopher Topham, Romain Irague, Clément Auriol, Audrey Baylac, et al.. Construction of a synthetic metabolic pathway for biosynthesis of the non-natural methionine precursor 2,4-dihydroxybutyric acid. Nature Communications, 2017, 8 (1), pp.15828. ⟨10.1038/ncomms15828⟩. ⟨hal-01608248⟩