Using fungible biosensors to evolve improved alkaloid biosyntheses

Area of Science:

• Synthetic Biology
• Biochemistry
• Metabolic Engineering

Background:

• Microbial production of therapeutic plant metabolites is hindered by the difficulty of identifying enzymes that enhance yield.
• Genetically encoded biosensors offer a solution for identifying suitable enzymes, facilitating scaled production.

Purpose of the Study:

• To develop a general method for rapidly evolving specific and sensitive biosensors for various plant alkaloids.
• To demonstrate the utility of these biosensors in engineering microbial production pathways.

Main Methods:

• A combined screening and selection approach was used to refine transcription factor affinities and specificities.
• Biosensors were evolved for alkaloids including tetrahydropapaverine, papaverine, glaucine, rotundine, and noscapine.
• High-resolution structures were determined to understand evolutionary pathways of the effector-binding site.

Main Results:

• Highly specific (>100-fold preference) and sensitive (EC50 < 30 μM) biosensors were evolved for five target alkaloids.
• Structural analysis revealed adaptable effector-binding sites capable of accommodating diverse chemical moieties.
• An evolved biosensor enabled the streamlining of a pathway for tetrahydropapaverine, a pharmaceutical precursor, into a single enzyme.

Conclusions:

• The developed biosensor evolution method enables rapid engineering of microbial pathways for therapeutic alkaloid production.
• This approach overcomes bottlenecks in enzyme identification for enhanced metabolite yields.
• The findings pave the way for efficient biosynthesis of valuable pharmaceutical compounds.