Pyrimidine-like Universal Nucleobases for Stable DNA Duplexes
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Solution Overview
Problem
Current universal nucleobases fail to bind equally to both purine and pyrimidine nucleobases, leading to instability in DNA duplexes and rejection by DNA polymerases, which hinders applications in high-throughput sequencing and biohazard simulant development.
Innovation Solution
Design of pyrimidine-like universal nucleobases with high symmetry and tautomeric equilibrium close to unity, such as C-glycosides and N-glycosides, that present complementary hydrogen bonding patterns to both guanine and cytosine, allowing for equal affinity and incorporation by DNA polymerases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional universal nucleobases are used, then they can pair with multiple standard nucleobases, but the pairing stability is unequal and DNA polymerases reject them
Solution Approach 1:
The patent applies asymmetry by designing a nucleobase analog where one nitrogen atom in the six-membered ring is replaced by a carbon atom at a specific position, creating an asymmetric structure that nonetheless achieves symmetric binding behavior. This structural asymmetry allows the analog to present complementary hydrogen bonding patterns to both purine and pyrimidine nucleobases with equal affinity, resolving the contradiction between versatility and reliability.
Solution Approach 2:
The patent changes the chemical parameter of the nucleobase structure by replacing a nitrogen atom with a carbon atom, which alters the hydrogen bonding capacity and electronic distribution. This parameter change enables the analog to form stable duplexes with both purine and pyrimidine nucleobases while being accepted by DNA polymerases, thus improving both pairing versatility and reliability simultaneously.
2Adaptability or versatility
If hypoxanthine is used as a universal nucleobase, then it can approximate universal pairing, but it shows a wide range of melting temperatures and gives difficult-to-analyze sequence data
Solution Approach 1:
The patent changes the chemical structure parameter by replacing the nitrogen atom with carbon, which narrows the melting temperature range when paired with different standard nucleobases. This structural modification produces more consistent thermal stability and generates cleaner, more analyzable sequencing data compared to hypoxanthine, while maintaining universal pairing capability.
Solution Approach 2:
The patent creates a improved copy of the universal nucleobase concept by designing a new analog that replicates and enhances the desirable properties of hypoxanthine (universal pairing) while eliminating its deficiencies (temperature variability and data analysis difficulties). The new analog serves as a superior version that maintains the core function with improved performance characteristics.
3Adaptability or versatility
If azole carboxamides are used to mimic purines and pyrimidines, then they can rotate around the amide bond to present different hydrogen bonding patterns, but one conformational isomer is preferred making them disappointing as nucleobase analogs
Solution Approach 1:
The patent uses asymmetry in the molecular structure (replacing nitrogen with carbon at a specific position) to create a rigidified system that eliminates the conformational flexibility problems of azole carboxamides. This asymmetric structural modification locks the molecule into a stable configuration that nonetheless maintains the ability to pair with both purine and pyrimidine nucleobases, resolving the contradiction between flexibility and stability.
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
These nucleobases stabilize DNA duplexes and are accepted by polymerases and ligases, reducing library degeneracy and enhancing sequencing efficiency and biohazard simulant effectiveness.
Implementation Method 1
a nucleoside analog that forms a nucleobase pair with each of the two standard purine nucleobases (adenine and guanine) with equal (or nearly equal) facility
Data Source
AI summary
This invention relates to the field of nucleic acid chemistry, more specifically to the field of compositions and processes that can bind to nucleic acids, including compositions and processes that by doing so have use in the capture, detection and sequencing of nucleic acids, and most specifically to nucleoside analogs that incorporate nucleobase analogs that are able to bind to different natural nucleobases with nearly equal affinity, and therefore display a degree of ambiguity, or universality, in their binding pattern. Such nucleobase analogs, when incorporated into oligonucleotides, allow the oligonucleotides to bind with nearly equal affinity and/or melting temperature, to a complementary strand, template the synthesis of oligonucleotide from primers that have a distribution of sequences, and support the sequencing of oligonucleotides. Thus, these have use in human diagnostics, especially when polymorphisms are present in a population.