Thermostable RNA Capping Enzymes for Structured RNA Yield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current enzymatic RNA capping methods are inefficient and vary in yield based on RNA sequence, often requiring large enzyme amounts or extensive purification, especially for RNAs with secondary structures.
Innovation Solution
A method involving a single-chain RNA capping enzyme with TPase, GTase, and N7 MTase activities, such as those from Faustovirus or Mimivirus, is used to cap RNA at elevated temperatures (37° C.-60° C.) with GTP and a buffering agent, improving efficiency by up to 3-fold compared to 37° C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If enzymatic RNA capping is performed at conventional temperature (37°C), then the reaction proceeds with standard enzyme stability, but the capping efficiency is low requiring large enzyme amounts
Solution Approach 1:
The patent applies parameter changes by optimizing the reaction temperature from the conventional 37°C to a higher range of 40-60°C. This temperature parameter change significantly improves the capping efficiency of the RNA capping enzyme, allowing the reaction to proceed effectively with much lower enzyme concentrations (as low as 0.1-10 nM compared to conventional micromolar ranges), thereby resolving the contradiction between productivity and quantity of enzyme required
Solution Approach 2:
The patent employs dynamics by using a thermostable RNA capping enzyme that maintains optimal activity across a dynamic temperature range of 40-60°C. The enzyme's thermostability allows the reaction system to dynamically operate at elevated temperatures without enzyme denaturation, enabling sustained high capping efficiency while reducing enzyme quantity requirements
2Productivity
If enzymatic RNA capping is performed with standard enzyme concentrations, then the reaction is simple to conduct, but the yield of capped RNA is low especially for RNAs with secondary structures
Solution Approach 1:
The patent applies parameter changes by optimizing reaction temperature to 40-60°C, which dramatically improves capping yield even for RNAs with secondary structures. This temperature optimization enables the enzyme to effectively access and cap structured RNAs that are refractory to capping at lower temperatures, achieving high yields without requiring complex purification protocols to remove uncapped RNA
Solution Approach 2:
The patent uses a thermostable RNA capping enzyme as an intermediary that bridges the gap between challenging substrates (RNAs with secondary structures) and the capping reaction. This specialized enzyme acts as a mediator that can effectively process structured RNAs at elevated temperatures, achieving high conversion yields without requiring additional purification steps
3Productivity
If capping reaction is performed at elevated temperature (40-60°C), then the capping efficiency increases up to 3-fold, but the enzyme must be thermostable
Solution Approach 1:
The patent applies parameter changes by selecting and using a thermostable RNA capping enzyme that maintains optimal catalytic activity at elevated temperatures of 40-60°C. This enzyme's thermostability is a key parameter change that enables the system to operate at higher temperatures without enzyme denaturation, achieving up to 3-fold improvement in capping efficiency while maintaining enzyme reliability and stability throughout the reaction
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 method achieves high yields of capped RNA, efficiently handling RNAs with secondary structures, reducing enzyme requirements, and enhancing capping efficiency by up to 3-fold.
Implementation Method 1
contacting (i) an RNA sample comprising an uncapped target RNA, (ii) an RNA capping enzyme comprising an amino acid sequence that is at least 90% identical to (e.g., at least 95% identical to) SEQ ID NOS: 1, 7 or 20, (iii) guanosine triphosphate (GTP) or modified GTP
Implementation Method 2
contacting (i) an RNA sample comprising an uncapped target RNA, (ii) an RNA capping enzyme comprising an amino acid sequence that is at least 90% identical to (e.g., at least 95% identical to) SEQ ID NOS: 1, 7 or 20, (iii) guanosine triphosphate (GTP) or modified GTP. (iv) a buffering agent
Implementation Method 3
contacting (i) an RNA sample comprising an uncapped target RNA, (ii) an RNA capping enzyme comprising an amino acid sequence that is at least 90% identical to (e.g., at least 95% identical to) SEQ ID NOS: 1, 7 or 20, (iii) guanosine triphosphate (GTP) or modified GTP. (iv) a buffering agent at a temperature in the range of 40° C.-60° C.
Data Source
AI summary
Provided herein is a method for efficiently capping RNA in vitro. In some embodiments the capping reaction may be done at high temperature using Vaccinia capping enzyme or a variant thereof. In other embodiments, the capping reactions may comprise a capping enzyme from a large virus of amoeba, e.g., Faustovirus, mimivirus or moumouvirus, or a variant thereof. Compositions and kits for practicing the method are also provided.