Fig. 5: Optimization to improve bikaverin titer using promoter exchange and enzyme fusion strategies.
From: Pathway engineering in yeast for synthesizing the complex polyketide bikaverin
a Driving bik2 and bik3 using PGAL1 led to a modest increase (yZM031). Promoters used are shown in different color rectangles. Fusing Bik2 and Bik3 led to a dramatic increase in bikaverin titer (yZM037), 60-fold higher than the original strain (yZM009). The strain with the ‘opposite polarity’ fusion as Bik3–Bik2 produced no bikaverin (yZM042). b Substrates channel model between Bik2 and Bik3. The fusion of Bik2 and Bik3 may form a short and adaptive substrate channel. c Relative protein expression levels of Bik2–His6, Bik3–His6, fusion proteins Bik3–Bik2–His6 and Bik2–Bik3–His6 using PGAL1 promoter by quantitative western blotting. Each protein was fused with 6×His-tag at its C-terminus. Protein expression level was measured as the intensity of target protein band divided by the intensity of the GAPDH band. d The bikaverin titer from flask fermentation. Strain yZM037 was cultured in YP medium supplemented with 20 or 40 g/L galactose as the carbon source. Data in a, c, d are presented as mean values ± SD from n = 3 biological replicates. Source data underlying a, c, and d are provided as a Source Data file.
