Warm-Start DNA Polymerase for Specific Isothermal Amplification
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Solution Overview
Problem
Non-specific amplification in nucleic acid detection technologies, particularly in isothermal amplification methods like LAMP, leads to reduced sensitivity and efficiency due to primer mismatch and non-template amplification, with few effective solutions available to address this issue.
Innovation Solution
A modified DNA polymerase fused with a G-quadruplex binding peptide and an aptamer that inhibits polymerase activity at low temperatures and restores it at higher temperatures, using a G-quadruplex core sequence to bind and detach from the peptide, combined with a biosynthesis method to create a warm-start DNA polymerase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If isothermal amplification is used for nucleic acid detection, then amplification efficiency is improved, but non-specific amplification occurs reducing sensitivity
Solution Approach 1:
The patent applies preliminary action by pre-incubating the DNA polymerase with the aptamer at low temperature before the amplification reaction begins. This pre-complex formation ensures that the polymerase is blocked and cannot initiate non-specific amplification during sample preparation and reagent mixing, while the aptamer-polymerase complex remains stable until the actual amplification temperature is reached
Solution Approach 2:
The patent utilizes parameter changes by exploiting the temperature-dependent binding affinity between the aptamer and DNA polymerase. At low temperatures (4-25°C), the aptamer binds strongly to inhibit polymerase activity. When the temperature is raised to the amplification range (37-65°C), the binding affinity decreases, releasing the polymerase to perform specific amplification. This temperature-driven parameter change dynamically controls enzyme activity throughout the reaction process
2Measurement precision
If DNA polymerase activity is blocked at low temperatures to prevent non-specific amplification, then detection sensitivity is improved, but polymerase activity must be restored at higher temperatures
Solution Approach 1:
The patent applies self-service by designing a system where the aptamer-polymerase complex automatically responds to temperature changes without external intervention. The complex self-regulates polymerase activity based on the thermal environment: inhibited at low temperatures and activated at high temperatures. This eliminates the need for separate activation steps or complex control mechanisms
Solution Approach 2:
The patent uses the aptamer as an intermediary molecule that mediates between the DNA polymerase and the temperature condition. The aptamer acts as a molecular switch that translates temperature changes into enzymatic activity changes, providing a simple yet effective control mechanism that avoids complex device requirements
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 modified DNA polymerase effectively prevents non-specific amplification, ensuring high sensitivity and specificity in nucleic acid detection, particularly for HPV DNA and SARS-CoV-2 RNA, by controlling polymerase activity through temperature-dependent binding and detachment.
Implementation Method 1
the G-quadruplex is configured to bind to the G-quadruplex binding peptide of the DNA polymerase at a first preset temperature to inhibit the activity of the DNA polymerase, and configured to detach from the G-quadruplex binding peptide of the DNA polymerase at a second preset temperature, to restore the activity of the DNA polymerase
Implementation Method 2
by controlling polymerase activity through temperature-dependent binding and detachment
Data Source
AI summary
A modified DNA polymerase includes a DNA polymerase fragment and a G-quadruplex binding peptide fused to an N-terminal of the DNA polymerase fragment.