alpha-Hydroxylation of Carboxylic Acids Catalyzed by Taurine Dioxygenase

摘要

Enzymes still have a limited application scope in synthetic organic chemistry. To expand this, different strategies exist that range from the denovo design of enzymes to the exploitation of the catalytic capabilities of known enzymes by converting different substrates; denoted as substrate promiscuity. We harnessed the synthetic potential offered by the taurine dioxygenase (TauD) from Escherichia coli (E.coli) by studying its promiscuous catalytic properties in the hydroxylation of carboxylic acid substrates. TauD showed high selectivities in the hydroxylation reaction but reduced levels of activity (26% conversion, 96% ee). We enhanced the enzyme substrate scope and improved the conversions for the tested substrates by introducing a point mutation at position 206 (F206Y). The conversions of the improved catalyst increased by at least 140% compared to that of the wild-type enzyme. The number of carboxylic acids that accepted by the enzyme variant doubled from four to eight carboxylic acids.