Engineering of a novel biochemical pathway for the biosynthesis of L-2-aminobutyric acid in Escherichia coli K12.
L-2-Aminobutyric acid was synthesised in a transamination reaction from L-threonine and L-aspartic acid as substrates in a whole cell biotransformation using recombinant Escherichia coli K12. The cells contained the cloned genes tyrB, ilvA and alsS which respectively encode tyrosine aminotransferase of E. coli, threonine deaminase of E. coli and alpha-acetolactate synthase of B. subtilis 168. The 2-aminobutyric acid was produced by the action of the aminotransferase on 2-ketobutyrate and L-aspartate. The 2-ketobutyrate is generated in situ from L-threonine by the action of the deaminase, and the pyruvate by-product is eliminated by the acetolactate synthase. The concerted action of the three enzymes offers significant yield and purity advantages over the process using the transaminase alone with an eight to tenfold increase in the ratio of product to the major impurity.
Fotheringham
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Biosciences, NSC Technologies, Mt. Prospect, IL 60056, USA. igfoth@ccmail.monsanto.com
Grinter
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N
Pantaleone
D P
DP
Senkpeil
R F
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Taylor
P P
PP
D000095:Acetolactate Synthase / Q000235:genetics / Q000378:metabolism; D000613:Aminobutyrates / Q000378:metabolism*; D001224:Aspartic Acid / Q000378:metabolism; D002087:Butyrates / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005818:Genetic Engineering / Q000379:methods*; D019289:Pyruvic Acid / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013912:Threonine / Q000378:metabolism; D013913:Threonine Dehydratase / Q000235:genetics / Q000378:metabolism; D000637:Transaminases / Q000235:genetics / Q000378:metabolism
D000613:Aminobutyrates; D002087:Butyrates; D011994:Recombinant Proteins; D013912:Threonine; D001224:Aspartic Acid; C005087:alpha-ketobutyric acid; D019289:Pyruvic Acid; D000095:Acetolactate Synthase; D000637:Transaminases; D013913:Threonine Dehydratase