Engineered FapR Biosensors for Broader Polyketide Extender Detection
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Solution Overview
Problem
Existing biosensors for polyketide extender units, particularly malonyl-CoA derivatives, are limited in their ability to detect a broad range of these molecules, hindering high-throughput strategies in metabolic engineering and limiting applications in important classes of molecules such as biofuels, antibiotics, and anticancer drugs.
Innovation Solution
A genetically modified FapR-based biosensor system with engineered nucleic acids and promoters is developed, capable of detecting malonyl-CoA and its derivatives, including methylmalonyl-CoA, by leveraging the promiscuity of the FapR transcriptional regulator to recognize a variety of acyl-thioesters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wild-type FapR is used as a biosensor, then it can detect malonyl-CoA, but it cannot detect C2-derivatives of malonyl-CoA or other polyketide extender units
Solution Approach 1:
The patent applies parameter changes by mutating specific amino acid residues in the FapR ligand-binding domain (particularly in the S1 and S2 sub-pockets) to alter its substrate recognition properties. This enables the engineered FapR variants to accommodate different polyketide extender units beyond native malonyl-CoA, thereby expanding detection range while maintaining measurable specificity through controlled structural modifications.
2Adaptability or versatility
If FapR is engineered to detect a broad range of polyketide extender units, then versatility improves, but the ability to distinguish between specific ligands may be reduced
Solution Approach 1:
The patent applies local quality by making targeted amino acid substitutions in specific regions of the FapR ligand-binding domain (S1 and S2 sub-pockets) rather than global modifications. This allows the biosensor to maintain distinct local binding characteristics that can differentiate between specific ligands while simultaneously accommodating a broader range of polyketide extender units through modified local interactions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The biosensor system provides a platform for detecting a range of polyketide extender units, enabling improved metabolic engineering and high-throughput strategies for producing diverse bioactive compounds like biofuels, antibiotics, and anticancer drugs.
Implementation Method 1
Crystal structures of FapR indicate a dimer, whereby each monomer is comprised of a C-terminal ligand-binding domain and an N-terminal domain that binds to its cognate DNA operator, fapO.
Implementation Method 2
FapR has been shown to act as either an activator or a repressor in the presence of its native ligand, mCoA.
Data Source
AI summary
The present disclosure relates to biosensors and uses thereof for detecting polyketide extender units. Disclosed herein are biosensor systems and methods for detecting polyketide synthase extender units. In some aspects, disclosed herein is a biosensor system comprising: a first nucleic acid comprising a genetically modified fapR gene, wherein the nucleic acid comprises at least one genetic mutation when compared to the wild-type fapR gene, and wherein the first nucleic acid is operably linked to a first promoter; and a second nucleic acid comprising a reporter gene whose transcription is under the control of a second promoter which is regulated by the fapR transcription factor.