Abasic DNA Probe Crosslinking for Stable Mutation Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Covalent approaches for the detection of specific nucleic acid sequences in molecular biology and medicine are less common due to a lack of practical and predictable reactions for covalent attachment of probes to target sequences, leading to instability and signal degradation in hybridization-based assays.
Innovation Solution
A method involving the incubation of a hybridized, double-stranded nucleic acid molecule with a target strand containing a 2'-deoxyguanosine (dG) and a partially complementary probe strand with an abasic (Ap) residue, allowing a covalent cross-link to form under specific conditions, particularly using NaCNBH3 and controlled pH, to create a stable probe-target complex.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hybridization-based assays are used for nucleic acid detection, then the detection can be performed with simple probe-target binding, but the probe-target complex is unstable and susceptible to denaturation causing signal degradation
Solution Approach 1:
The patent creates a composite structure by forming a covalent cross-link between the probe and target nucleic acid strands. The Abasic site in the probe forms a covalent bond with the guanine residue in the target, creating a hybrid complex that combines the specificity of hybridization with the stability of covalent bonding. This composite probe-target-crosslink complex resists denaturation while maintaining the simplicity of the hybridization-based approach.
2Reliability
If covalent cross-linking reactions are used to anchor probes to target sequences, then the probe-target complex becomes stable and resistant to denaturation, but the lack of practical and predictable reactions reduces detection selectivity
Solution Approach 1:
The patent introduces a localized reactive site (Abasic site) at a specific position in the probe sequence, immediately 3' adjacent to the nucleotide opposite the target guanine. This local modification creates a predictable and selective cross-linking reaction at the desired location, ensuring that cross-linking only occurs when the probe is correctly hybridized to the complementary target sequence, thereby maintaining high selectivity.
Solution Approach 2:
The patent optimizes reaction parameters including pH (lesser than 7.0, preferably 4.5-6.5) and temperature to control the cross-linking reaction. By adjusting these parameters, the reaction achieves optimal selectivity for the probe-target complex while minimizing non-specific cross-linking, thereby improving measurement precision without sacrificing stability.
3Reliability
If covalent cross-linking is employed for nucleic acid detection, then signal stability is improved, but the complexity of achieving sequence-specific cross-linking increases
Solution Approach 1:
The Abasic site acts as an intermediary element that facilitates the cross-linking reaction. It provides a reactive aldehyde group that can covalently bond with the amino group of guanine in the target sequence. This intermediary approach simplifies the overall reaction design by using a well-characterized chemical intermediate that enables predictable and selective cross-linking without requiring complex reaction conditions or multiple steps.
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 method enhances selectivity and stability of nucleic acid detection, enabling quantitative and qualitative assessment of target sequences, including disease-relevant mutations, by forming distinguishable crosslinked nucleic acid strands detectable through gel electrophoresis, fluorescence, electrochemistry, or nanopore-based sensors.
Implementation Method 1
incubation occurs under conditions that allow for a covalent cross link to form between the Ap residue of the probe strand and the target dG
Implementation Method 2
covalent cross-linking reactions can be used to anchor the probe strand to its target sequence thereby generating a probe-target complex that is impervious to denaturation
Implementation Method 3
the incubation occurs in the presence of NaCNBH3
Implementation Method 4
covalently crosslinked nucleic acid strands detectable through gel electrophoresis
Data Source
AI summary
Provided herein are probes in which an Ap site of a probe strand can selectively cross-link with a 2′-deoxyguanosine (dG) of a target strand. Also provided for are methods of using such probes to generate and detect crosslinked molecules and methods of detecting disease associated genetic mutations.