Non-standard Nucleotide PCR Amplification via Chimeric Primers
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Solution Overview
Problem
Current PCR technologies face challenges in amplifying oligonucleotides containing multiple non-standard nucleotides, as polymerases tend to lose or misincorporate these nucleotides during multiple cycles, leading to instability and inefficiency.
Innovation Solution
The process involves using chimeric primers with non-standard nucleotides in nested PCR formats, where external primers containing dZ and dP allow for successful amplification by maintaining the stability of these nucleotides through specific hydrogen bonding patterns, and using polymerases like Phusion for high fidelity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If standard PCR amplification is used with non-standard nucleotides, then amplification can be performed, but polymerases lose or misincorporate non-standard nucleotides during multiple cycles
Solution Approach 1:
The patent modifies the chemical structure of nucleotides by introducing non-standard bases (dZ and dP) with specific hydrogen bonding patterns that differ from natural DNA bases. These parameter changes in nucleotide structure enable stable incorporation and retention during PCR amplification, resolving the contradiction between amplification efficiency and nucleotide stability.
Solution Approach 2:
The patent creates composite nucleic acid structures by combining standard nucleotides (dNTPs) with non-standard nucleotides (dZTP and dPTP) in the same oligonucleotide sequence. This composite approach allows the molecule to maintain both the stability of standard bases and the functional properties of non-standard bases throughout multiple PCR cycles.
2Adaptability or versatility
If multiple non-standard nucleotides are incorporated into oligonucleotides, then diverse base pairing patterns are achieved, but polymerase fidelity decreases
Solution Approach 1:
The patent applies different hydrogen bonding patterns at specific local positions within the oligonucleotide sequence. The dZ:dP base pairs with a distinctive hydrogen bonding pattern (pyDDA/puAAD) that differs from standard Watson-Crick pairing, allowing local functional diversity while maintaining overall polymerase compatibility through optimized structural properties at each position.
3Reliability
If nested PCR format is used with chimeric primers, then successful amplification of multiple non-standard nucleotides is achieved, but process complexity increases
Solution Approach 1:
The patent divides the PCR process into nested stages with different primer sets. External primers contain non-standard nucleotides for initial amplification, while internal primers enable subsequent amplification of the same template. This segmentation allows systematic optimization of each amplification stage, improving overall reliability while managing process complexity through structured organization.
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 successful PCR amplification with multiple dPs and dZs, producing cleaner PCR products and maintaining high fidelity, even in multiplexed reactions, by utilizing specific polymerases and optimized conditions.
Implementation Method 1
oligonucleotides incorporate nucleotide analogs ('non-standard nucleotides') that form base pairs joined by hydrogen bonding patterns not found in standard nucleotides A, T, G and C
Data Source
AI summary
The disclosed invention teaches processes to create a Watson-Crick complementary copy of a preselected oligonucleotide that contain non-standard nucleotides, which form nucleobase pairs fitting the standard Watson-Crick geometry, but here said pairs are joined by hydrogen bonding patterns different from those that join standard A:T and G:C pairs. The invention further relates to polymerases that incorporate those non-standard nucleotide analogs into oligonucleotide products using the corresponding triphosphate derivatives.