The promiscuous N-hydroxylating monooxygenase GorA and its application in cascades

N -hydroxy compounds are valuable building blocks for the biosynthesis of various bioactive compounds. Here, the biosynthesis of N -hydroxyputrescine (OH-Put) and N -hydroxycadaverine (OH-Cad) using ornithine and lysine as starting materials was achieved in an enzymatic cascade. The setup involved the N -hydroxylating monooxygenase GorA and decarboxylase GorB, both from Gordonia rubripertincta CWB2, and an NADP + -accepting formate dehydrogenase variant. Starting from 5 mM substrate, OH-Put or OH-Cad concentrations of approximately 3.6 mM or 2.5 mM, respectively, were reached within 24 h. An extraction method with 4-nonylphenol resulted in total OH-Cad recovery of 71%. Subsequent chemical coupling reaction with 4-sulfobenzendiazonium chloride resulted in the respective N -hydroxytriazene, demonstrating the expandability of the enzymatic cascade to a stable and valuable product. Furthermore, we show the versatility of this cascade by showcasing an even wider substrate spectrum of GorA, which was able to convert diamine derivatives such 2-methylcadaverine, cystamine, agmatine, and diethylentriamine.