Reverse Transcriptase–Cold Shock Protein Fusion for Full-Length cDNA
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Solution Overview
Problem
Existing reverse transcriptase enzymes face challenges in synthesizing full-length cDNA from long RNA templates, particularly those with secondary structures, due to limitations in processivity, which affects the efficiency of genetic studies in biology, medicine, and agriculture.
Innovation Solution
A recombinant fusion protein is developed by linking a cold shock protein (Csp) to a reverse transcriptase (RT), enhancing the enzyme's processivity and ability to synthesize long-stranded cDNA at lower temperatures, including secondary structure-rich RNA templates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional reverse transcriptase is used, then the enzyme can perform reverse transcription, but it cannot synthesize full-length cDNA from long RNA templates due to limited processivity
Solution Approach 1:
The patent merges cold shock protein (Csp) with reverse transcriptase (RT) to create a fusion protein. The Csp domain enhances the processivity of the RT enzyme, enabling it to synthesize full-length cDNA from long RNA templates (up to 15 kb) that conventional RT cannot process. This combination resolves the contradiction by integrating a processivity-enhancing domain with the catalytic RT domain.
Solution Approach 2:
The fusion protein represents a composite enzyme structure combining two functional domains: the Csp domain from cold shock proteins and the RT domain from reverse transcriptase. This composite structure leverages the nucleic acid-binding properties of Csp to enhance the processivity of RT, achieving full-length cDNA synthesis from long templates while maintaining the catalytic function of RT.
2Stability of the object's composition
If temperature is lowered to improve RNA template stability, then secondary structure-rich RNA can be maintained, but reverse transcription efficiency decreases
Solution Approach 1:
The fusion of Csp with RT creates a protein that can function effectively at lower temperatures. The Csp domain stabilizes the enzyme-RNA complex at temperatures as low as 4°C, allowing reverse transcription to proceed efficiently while maintaining RNA template stability and preventing secondary structure formation that would hinder transcription.
Solution Approach 2:
The fusion protein enables reverse transcription to occur at a broader temperature range, particularly at lower temperatures (4-37°C) where conventional RT shows reduced efficiency. The Csp domain confers thermal stability and cold-adaptation properties, allowing the enzyme to maintain high activity at temperatures that preserve RNA template integrity.
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 fusion protein significantly improves the synthesis of long-stranded cDNA, achieving full-length transcription of RNA templates up to 15 kb at temperatures as low as 42°C, outperforming conventional RTs in efficiency and versatility.
Implementation Method 1
Cold shock proteins are found in various organisms, particularly in microorganisms, to cope with stress and to adapt to changing environment such as downshifting growth temperature
Data Source
AI summary
The present disclosure provides a recombinant reverse transcriptase with improved processivity and the use thereof. In one embodiment, the recombinant reverse transcriptase is a fusion protein comprising a reverse transcriptase and a cold shock protein.