Mutant Reverse Transcriptase Thermal Stability
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Solution Overview
Problem
Conventional reverse transcriptases, such as Moloney murine leukemia virus and avian myeloblastosis virus, have low thermal stability, which limits their ability to inhibit RNA secondary structure formation during cDNA synthesis, as they are inactivated at temperatures needed to prevent secondary structure formation.
Innovation Solution
A mutant reverse transcriptase with specific amino acid substitutions in the DNA interaction region, including changes at positions 124, 286, 302, and 435, that introduce positively-charged or nonpolar residues, enhancing thermal stability and allowing for reverse transcription at higher temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reaction temperature is elevated to inhibit RNA secondary structure formation, then cDNA synthesis efficiency is improved, but reverse transcriptase is inactivated due to low thermal stability
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of reverse transcriptase at specific positions (124, 286, 302, 435) to alter its thermal stability properties. These substitutions change the enzyme's physical parameters to maintain activity at higher temperatures, enabling cDNA synthesis at temperatures that prevent RNA secondary structure formation while keeping the enzyme functional.
Solution Approach 2:
The patent applies local quality by making specific localized amino acid substitutions at four key positions in the reverse transcriptase structure. Rather than changing the entire enzyme, targeted modifications are made at specific locations to enhance thermal stability while preserving overall catalytic function. This localized approach allows the enzyme to resist thermal inactivation at specific critical regions.
2Reliability
If amino acid substitutions are made to improve thermal stability, then enzyme stability at high temperature is improved, but reverse transcriptase activity may be reduced
Solution Approach 1:
The patent carefully selects amino acid substitutions that change local charge and hydrophobicity parameters without disrupting the catalytic core. The substitutions at positions 124, 286, 302, and 435 are chosen to enhance thermal stability through improved electrostatic interactions and packing, while maintaining the enzyme's ability to bind RNA and catalyze polymerization.
Solution Approach 2:
The patent applies local quality by making specific localized amino acid substitutions at four key positions in the reverse transcriptase structure. Rather than changing the entire enzyme, targeted modifications are made at specific locations to enhance thermal stability while preserving overall catalytic function. This localized approach allows the enzyme to resist thermal inactivation at specific critical regions.
Data Source
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AI summary
The present invention provides a versatile mutant reverse transcriptase with high thermal stability, a nucleic acid thereof and a method for producing a mutant reverse transcriptase, a versatile kits for reverse transcription and detection, a method for improving thermal stability of a nucleic acid-related enzyme, which significantly improves thermal stability of a nucleic acid-related enzyme, and a reverse transcription method, which efficiently performs a reverse transcription. An amino acid residue in a nucleic acid interaction region of a wild-type enzyme is substituted with a positively-charged amino acid residue or a nonpolar amino acid residue, to form a nucleic acid interaction region having a positive effective charge larger than the nucleic acid interaction region of a wild-type enzyme.