Isothermal DNA Amplification via Destabilizing Template Turnover
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Solution Overview
Problem
Current methods for isothermal DNA amplification face challenges in achieving turnover in ligation reactions due to the enhanced affinity of DNA templates for ligated products, limiting the ability to generate multiple copies of a target DNA sequence efficiently.
Innovation Solution
The method involves using destabilizing DNA probes to create a destabilizing template in situ, which allows for the isothermal amplification of a target DNA sequence through a cross-catalytic cycle, where the probes hybridize, ligate, and dissociate to generate multiple copies of the target sequence and destabilizing template, overcoming product inhibition by introducing destabilizing modifications that reduce the stability of the hybridization complex.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DNA templates are used to facilitate ligation reactions under isothermal conditions, then the reaction can proceed efficiently, but the template affinity for the ligated product is enhanced, causing minimal turnover and product inhibition
Solution Approach 1:
The patent introduces destabilizing modifications at specific local positions within the DNA template sequence. These modifications are placed strategically to reduce the stability of the hybridization complex between the template and ligated product, enabling turnover without compromising the overall ligation efficiency. The local destabilization allows the template to release the product and participate in multiple catalytic cycles.
Solution Approach 2:
The patent modifies the chemical parameters of the DNA template by incorporating unnatural base analogs or modified nucleotides that alter the thermodynamic stability of the hybridization complex. These parameter changes reduce the binding affinity between the template and product, facilitating product release and enabling isothermal turnover in ligation reactions.
2Productivity
If destabilizing modifications are introduced into the DNA template, then turnover is achieved, but the stability of the hybridization complex is reduced
Solution Approach 1:
The destabilizing modifications are introduced at specific local positions within the template sequence rather than throughout the entire sequence. This localized approach allows turnover to be achieved at critical positions while maintaining sufficient overall stability for reliable hybridization and ligation.
Solution Approach 2:
The patent applies partial destabilization by introducing modifications at selected positions rather than uniformly throughout the template. This partial action achieves the necessary turnover while maintaining enough stability for reliable operation, avoiding excessive destabilization that would prevent proper hybridization.
3Ease of operation
If isothermal amplification is performed without destabilizing modifications, then the reaction conditions are simplified, but product inhibition occurs and amplification efficiency is limited
Solution Approach 1:
The patent modifies the chemical composition parameters of the template by incorporating destabilizing modifications, which changes the thermodynamic properties of the hybridization complex. This parameter change enables isothermal amplification to proceed with high efficiency by preventing product inhibition, while maintaining the simplicity of isothermal reaction conditions.
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
This approach enables efficient isothermal amplification of DNA sequences, achieving higher turnover numbers and self-replication, with the ability to detect target sequences and identify genomic DNA or gene mutations, including single-point mutations, while minimizing background reactions and maintaining the reaction at a constant temperature.
Implementation Method 1
The probe destabilizing moiety comprises an abasic or model abasic, butyl, cis-butenyl, or ethyl group... By ligating strands at a destabilizing site, the stability of the hybridization complex can be modified without changing the temperature or any other reaction condition
Implementation Method 2
One strategy for introducing turnover into ligation reactions exploits the sensitivity of DNA to destabilizing modifications present in the middle of a duplex... If the stabilities of the complexes before and after ligation are properly balanced, isothermal turnover should be achieved
Implementation Method 3
The present invention relates to methods for isothermally amplifying a DNA sequence using a cross catalytic cycle whereby a destabilizing DNA template is generated in situ from destabilizing DNA probes and the target sequence copies are generated from another set of probes
Data Source
AI summary
The invention is directed to a method for isothermally amplifying a DNA sequence involving hybridizing a destabilizing DNA template to complementary nucleotide fragments to form a first nicked duplex; ligating the first nicked duplex to form a product duplex comprising the DNA sequence and the template, wherein the product duplex is capable of dissociating to release the DNA sequence and the template; and repeating these steps to generate multiple copies of the template and the DNA sequence. Further, the method may also involve hybridizing the DNA sequence to complementary destabilizing fragments or probes to form a second nicked duplex; ligating the second nicked duplex to form the product duplex comprising the DNA sequence and the template, wherein the product duplex dissociates to release the DNA sequence and the template; and repeating these steps to generate multiple copies of the template and the DNA sequence.