A multi-enzyme cascade for efficient production of d-p-hydroxyphenylglycine from l-tyrosine

In this study, a four-enzyme cascade pathway was developed and reconstructed in vivo for the production of d - p -hydroxyphenylglycine (D-HPG), a valuable intermediate used to produce β-lactam antibiotics and in fine-chemical synthesis, from l -tyrosine. In this pathway, catalytic conversion of the intermediate 4-hydroxyphenylglyoxalate by meso -diaminopimelate dehydrogenase from Corynebacterium glutamicum ( Cg DAPDH) was identified as the rate-limiting step, followed by application of a mechanism-guided “conformation rotation” strategy to decrease the hydride-transfer distance d (C6HDAP−C4NNADP) and increase Cg DAPDH activity. Introduction of the best variant generated by protein engineering ( Cg DAPDH BC621/D120S/W144S/I169P with 5.32 ± 0.85 U·mg −1 specific activity) into the designed pathway resulted in a D-HPG titer of 42.69 g/L from 50-g/L l -tyrosine in 24 h, with 92.5% conversion, 71.5% isolated yield, and > 99% enantiomeric excess in a 3-L fermenter. This four-enzyme cascade provides an efficient enzymatic approach for the industrial production of D-HPG from cheap amino acids.