Thio-phosphate Metabolic Engineering in E. coli
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Solution Overview
Problem
Current methods using thio-phosphate in microbial metabolic engineering primarily result in transcriptional regulatory changes, leading to shifts in metabolite distribution and protein synthesis, but lack targeted control over specific pathways like histidine, tryptophan, and fatty acid synthesis, and isoprenoids, due to non-specific effects on RNA turnover.
Innovation Solution
Employing thio-phosphate to enhance metabolic flux in E. coli by manipulating genetic pathways, particularly those using PRPP as an intermediate, through mutations and genetic engineering to redirect metabolites towards specific products such as histidine, tryptophan, and isoprenoids, while also increasing ribonucleotide production and fatty acid synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thio-phosphate is used as a phosphate source in microbial cultivation, then nucleic acid synthesis and cellular growth are enhanced, but metabolite distribution shifts away from targeted pathways due to non-specific transcriptional regulatory changes
Solution Approach 1:
The invention segments the broad transcriptional effect of thio-phosphate into specific pathway-controlled responses by introducing pathway-specific promoters (e.g., hisG promoter for histidine pathway, trpC promoter for tryptophan pathway) that selectively activate only the desired metabolic pathways while maintaining nucleic acid synthesis benefits
Solution Approach 2:
The invention uses pathway-specific promoters as intermediaries between thio-phosphate treatment and metabolic pathway activation. These promoters act as selective mediators that translate the general cellular stress signal into specific pathway activation, preventing non-specific metabolite distribution shifts
2Quantity of substance
If thio-phosphate is used to stabilize RNA and reduce turnover, then PRPP accumulates and increases amino acid synthesis, but transcriptional regulatory changes dominate over differential mRNA stabilization
Solution Approach 1:
The invention applies local quality control by using pathway-specific promoters that confer different regulatory properties to different metabolic pathways. Each promoter creates a localized regulatory environment that responds specifically to its associated pathway's metabolic state, ensuring precise control over PRPP utilization in targeted pathways while maintaining overall RNA stabilization benefits
3Manufacturing precision
If genetic pathways are manipulated to redirect metabolite flux towards specific products, then targeted compound production increases, but overall metabolic efficiency may be reduced due to pathway imbalances
Solution Approach 1:
The invention employs self-service mechanisms where pathway-specific promoters automatically sense and respond to the metabolic state of their associated pathways. When PRPP accumulates in a specific pathway, the corresponding promoter activates to redirect flux, creating a self-regulating system that maintains metabolic efficiency without external intervention while achieving targeted product production
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
This approach allows for targeted increases in production of specific organic compounds like histidine, tryptophan, and isoprenoids, enhancing metabolic flux and energy efficiency by stabilizing RNA and altering transcriptional profiles, thereby favoring less abundant proteins and increasing lipid synthesis.
Implementation Method 1
Thio-phosphate is incorporated into nucleic acids creating phosphorothioate linkages that are nuclease resistant
Implementation Method 2
The use of thio-phosphate results in profound transcriptional changes in E coli that ultimately redirect more metabolites towards the synthesis of fatty acids, isoprenolds, PRPP and its derivatives
Implementation Method 3
phosphoribosyl pyrophosphate (PRPP), an important intermediate in nucleic acid synthesis, may accumulate due to less turnover of RNA in the cell
Data Source
AI summary
The present invention describes the use of thio-phosphate in the metabolic engineering of E. coli. Thio-phosphate can be used to increase the metabolic flux in important synthetic pathways to enhance the production of bioproducts. The pathways impacted include the following: fatty acid synthesis, isoprenoid syntheses, Vit K2 synthesis, ribonucleotide synthesis, and the synthesis of phosphoribosyl pyrophosphate (PRPP) derivatives like 5-aminoimidazole-4-carboxamide (AICA riboside), histidine, and tryptophan. Thus, thio-phosphate can be used to assist in the production of these molecules and/or their derivatives. Enhanced production of AICA in Bacillus megaterium is also demonstrated.