Fig. 1

Engineering the raspberry ketone biosynthetic pathway in S. cerevisiae. a The phenylpropanoid pathway begins with the conversion of phenylalanine to p-coumaric acid via cinnamate or directly from tyrosine to p-coumaric acid (pink box). Conversion of p-coumaric acid to raspberry ketone requires three additional enzymatic steps including a condensation reaction between coumaroyl-CoA and malonyl-CoA. Heterologous production of raspberry ketone can be accomplished by the final three enzymatic reactions, if microbial cells are supplied with exogenous p-coumaric acid (blue box). The heterologous enzymes used for each reaction in this study are also listed. b Expression constructs used in this study for the production of raspberry ketone. Rigid and flexible linker sequences that were used for the protein fusions are represented by bold black lines (straight and wavy, respectively)