Chimeric Enzymes for Modified mRNA Synthesis
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Solution Overview
Problem
Current methods for therapeutic mRNA delivery face challenges such as low translation efficiency and immunogenicity, limiting their application in treating diseases, and there is a need for improved modulation of intracellular translation and processing of nucleic acids encoding polypeptides.
Innovation Solution
Development of chimeric enzymes for synthesizing chemically modified messenger RNA (mRNA) using phage-assisted continuous directed evolution (PACE) to incorporate unnatural chemical modifications, including capping enzymes and nucleic acid polymerases like T7 RNA polymerase variants and DNA polymerase mutants, which enhance transcription efficiency and allow for broader arrays of modified mRNA production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional in vitro transcription systems are used, then standard mRNA synthesis is achieved, but translation efficiency is low and immunogenicity remains high
Solution Approach 1:
The patent applies parameter changes by modifying chemical parameters of the mRNA molecule through incorporation of unnatural nucleoside analogs (e.g., pseudouridine, 5-methylcytosine, and other non-canonical nucleotides) at specific positions in the mRNA sequence. These chemical parameter modifications alter the mRNA's interaction with cellular machinery, thereby improving translation efficiency while reducing immunogenicity without changing the overall transcription process
Solution Approach 2:
The patent introduces intermediary substances - specifically, engineered polymerases and capping enzymes that facilitate the incorporation of modified nucleoside analogs during in vitro transcription. These intermediary enzymes mediate between the template DNA and the modified nucleotides, enabling the synthesis of chemically modified mRNA with improved properties
2Adaptability or versatility
If standard polymerases are used for in vitro transcription, then conventional mRNA production is achieved, but chemical modification capability is limited
Solution Approach 1:
The patent creates universal polymerase enzymes through directed evolution that can perform multiple functions: synthesizing RNA from DNA templates while simultaneously incorporating a broad range of chemically modified nucleoside analogs. These engineered polymerases have evolved to recognize and incorporate various unnatural nucleotides (including those with non-standard bases like pyridin-4-one ribonucleoside, 5-aza-uridine, and 2-thio-5-aza-uridine) while maintaining transcriptional activity
Solution Approach 2:
The patent employs parameter changes in the enzyme's active site through directed evolution mutations, allowing the polymerase to accommodate diverse chemical structures of modified nucleotides. Specific amino acid residues in the polymerase active site were mutated to expand substrate specificity, enabling the enzyme to process a wide array of chemically modified nucleoside triphosphates while maintaining efficient transcription
3Adaptability or versatility
If natural nucleosides are used in mRNA synthesis, then standard transcription is achieved, but production of broadly modified mRNA arrays is limited
Solution Approach 1:
The patent introduces engineered intermediary enzymes - specifically, a chemically modified nucleoside triphosphate-dependent polymerase and a capping enzyme - that mediate the incorporation of modified nucleosides and the formation of capped structures. These intermediary enzymes simplify the overall system by providing a single transcriptional platform that can generate diverse modified mRNA arrays through substrate variation rather than requiring separate synthesis pathways for each modification type
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 approach improves the efficiency of in vitro transcription and translation systems, enabling the production of chemically modified mRNA with increased translation efficiency and reduced immunogenicity, thereby overcoming previous limitations in therapeutic mRNA delivery.
Implementation Method 1
chimeric enzymes for synthesizing capped RNA molecules
Implementation Method 2
nucleic acid polymerases for in vitro transcription
Implementation Method 3
at least one capping enzyme and at least one nucleic acid polymerase
Data Source
AI summary
The invention relates to compositions and methods for the design, evolution, preparation, and/or manufacture of enzymes for use with polynucleotides, primary transcripts and mmRNA molecules.