Thermostable Polymerase Oligonucleotide Amplification
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Solution Overview
Problem
Current methods fail to sustainably amplify oligonucleotides containing non-standard nucleotides through polymerase chain reaction (PCR) due to inefficiencies in polymerase acceptance and stability issues, leading to significant loss of non-standard nucleobase pairs during thermal cycling.
Innovation Solution
The use of thermostable polymerases and specific non-standard nucleotides, such as 2′-deoxy-7-deazaisoguanosine and 2′-thiothymidine triphosphate, in PCR processes to maintain hydrogen-bonding patterns and stability, allowing for the retention of non-standard nucleobase pairs across multiple cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard polymerases are used for PCR amplification of oligonucleotides containing non-standard nucleotides, then the process can be initiated, but the non-standard nucleobase pairs are lost at rates greater than 90% over five cycles due to poor polymerase acceptance and stability
Solution Approach 1:
The patent applies parameter changes by modifying the polymerase enzyme's properties through engineering or selection to accept non-standard nucleotides. Specifically, the invention uses thermostable polymerases with altered fidelity or binding characteristics that enable them to incorporate and maintain non-standard nucleobase pairs (such as isocytosine-isoguanine) during thermal cycling, thereby reducing loss rates from >90% to acceptable levels for sustained amplification
Solution Approach 2:
The patent introduces intermediary components including specially designed primers containing non-standard nucleotides that facilitate initial incorporation, and optimized buffer conditions that stabilize the polymerase-nucleotide complex. These intermediaries bridge the gap between standard PCR machinery and non-standard nucleotide substrates, enabling reliable amplification
2Productivity
If thermostable polymerases are used to sustain PCR through thermal cycling, then amplification can continue over multiple cycles, but the polymerases make contacts with unshared electrons in the minor groove that cause loss of non-standard base pairs
Solution Approach 1:
The patent applies local quality by creating spatial differentiation in polymerase interactions along the DNA helix. The invention designs polymerases or modifies reaction conditions so that the polymerase active site makes favorable contacts with standard base pairs while minimizing or eliminating contacts with the minor groove regions containing unshared electrons that would otherwise destabilize non-standard base pairs like isocytosine-isoguanine
Solution Approach 2:
The patent segments the polymerase enzyme into functional domains, where certain regions are engineered or selected to have high affinity for standard nucleotides while other regions are modified to have reduced affinity or neutral interaction with non-standard nucleotides. This segmentation allows the polymerase to perform its amplification function while selectively preserving non-standard base pairs
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 effective amplification of oligonucleotides with reduced nucleobase loss, achieving stable PCR processes that retain over 90% of non-standard nucleobases, enhancing the utility of PCR for diagnostics and in vitro applications.
Implementation Method 1
maintain hydrogen-bonding patterns and stability, allowing for the retention of non-standard nucleobase pairs across multiple cycles
Data Source
AI summary
This invention relates to processes that amplify oligonucleotide analogs that incorporate non-standard nucleobase analogs from an artificially expanded genetic information system. These pair in DNA duplexes via patterns of hydrogen bonds that differ from patterns that join the thymine-adenine and guanine-cytosine nucleobase pairs.