Synthesis of rosmarinic acid analogues in Escherichia coli

To produce rosmarinic acid analogues in the recombinant Escherichia coli BLRA1, harboring a 4-coumarate: CoA ligase from Arabidopsis thaliana (At4CL) and a rosmarinic acid synthase from Coleus blumei (CbRAS). Incubation of the recombinant E. coli strain BLRA1 with exogenously supplied phenyllactic acid (PL) and analogues as acceptor substrates, and coumaric acid and analogues as donor substrates led to production of 18 compounds, including 13 unnatural RA analogues. This work demonstrates the viability of synthesizing a broad range of rosmarinic acid analogues in E. coli, and sheds new light on the substrate specificity of CbRAS.