One-pot synthesis of amino-alcohols using a de-novo transketolase and β-alanine: Pyruvate transaminase pathway in Escherichia coli

Authors

  • C.U. Ingram,

    1. Department of Biochemical Engineering, University College London, London, WC1E 7JW, United Kingdom; telephone: +44 (0)20 7679 7942; fax: +44 (0)20 7209 0703;
    Current affiliation:
    1. Novacta Biosystems Ltd, UH Innovation centre, University of Hertfordshire, Hatfield, AL10 9AB
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  • M. Bommer,

    1. Department of Biochemistry and Molecular Biology, University College London, London, WC1E 7JW, United Kingdom
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  • M.E.B. Smith,

    1. Department of Chemistry, University College London, London, WC1E 7JW, United Kingdom
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  • P.A. Dalby,

    1. Department of Biochemical Engineering, University College London, London, WC1E 7JW, United Kingdom; telephone: +44 (0)20 7679 7942; fax: +44 (0)20 7209 0703;
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  • J.M. Ward,

    1. Department of Biochemistry and Molecular Biology, University College London, London, WC1E 7JW, United Kingdom
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  • H.C. Hailes,

    1. Department of Chemistry, University College London, London, WC1E 7JW, United Kingdom
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  • G.J. Lye

    Corresponding author
    1. Department of Biochemical Engineering, University College London, London, WC1E 7JW, United Kingdom; telephone: +44 (0)20 7679 7942; fax: +44 (0)20 7209 0703;
    • Department of Biochemical Engineering, University College London, London, WC1E 7JW, United Kingdom; telephone: +44 (0)20 7679 7942; fax: +44 (0)20 7209 0703;
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Abstract

Biocatalysis continues to emerge as a powerful technique for the efficient synthesis of optically pure pharmaceuticals that are difficult to access via conventional chemistry. The power of biocatalysis can be enhanced if two or more reactions can be achieved by a single whole cell biocatalyst containing a pathway designed de-novo to facilitate a required synthetic sequence. The enzymes transketolase (TK) and transaminase (TAm) respectively catalyze asymmetric carbon[BOND]carbon bond formation and amine group addition to suitable substrate molecules. The ability of a transaminase to accept the product of the transketolase reaction can allow the two catalysts to be employed in series to create chiral amino-alcohols from achiral substrates. As proof of principle, the β-alanine: pyruvate aminotransferase (β-A:P TAm) from Pseudomonas aeruginosa has been cloned, to create plasmid pQR428, for overexpression in E.coli strain BL21gold(DE3). Production of the β-A:P TAm alongside the native transketolase (overexpressed from plasmid pQR411), in a single E.coli host, has created a novel biocatalyst capable of the synthesis of chiral amino alcohols via a synthetic two-step pathway. The feasibility of using the biocatalyst has been demonstrated by the formation of a single diastereoisomer of 2-amino-1,3,4-butanetriol (ABT) product, in up to 21% mol/mol yield, by the β-A:P TAm, via transamination of L-erythrulose synthesized by TK, from achiral substrates glycolaldehyde (GA) and β-hydroxypyruvate (β-HPA). ABT synthesis was achieved in a one-pot process, using either whole cells of the dual plasmid strain or cell lysate, while the dual alcohol-amine functionality of ABT makes it an excellent synthon for many pharmaceutical syntheses. Biotechnol. Bioeng. 2007;96: 559–569. © 2006 Wiley Periodicals, Inc.

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