XPD Helicase Nanopore Sequencing Accuracy
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Solution Overview
Problem
Current polynucleotide sequencing technologies are slow and expensive due to reliance on amplification techniques and high quantities of specialist fluorescent chemicals, necessitating a more rapid and cost-effective method for DNA or RNA sequencing.
Innovation Solution
A method utilizing an XPD helicase to control the movement of a target polynucleotide through a transmembrane pore, allowing for electrical and optical measurements to characterize the polynucleotide, particularly at high salt concentrations, enabling efficient sequencing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If amplification techniques and specialist fluorescent chemicals are used for polynucleotide sequencing, then sequencing accuracy can be achieved, but the process becomes slow and expensive
Solution Approach 1:
The invention extracts and eliminates the need for amplification techniques and specialist fluorescent chemicals from the sequencing process. By using nanopore detection with XPD helicase, the method directly sequences polynucleotides without requiring PCR amplification or fluorescent labeling, thereby removing the bottlenecks that cause slowness and high cost while maintaining sequencing accuracy through direct electrical detection of nucleotide translocation
Solution Approach 2:
The invention replaces the optical/chemical detection system (fluorescent chemicals and optical detection) with an electrical detection system based on nanopore current measurements. The XPD helicase mechanically controls polynucleotide translocation through the nanopore, and nucleotide identity is determined by characteristic current blockades, eliminating the need for slow optical detection processes while improving sequencing speed
2Quantity of substance
If amplification techniques are used to produce large volumes of polynucleotide, then sufficient signal for detection can be obtained, but the process becomes expensive and time-consuming
Solution Approach 1:
The nanopore detection system is highly sensitive and can detect single polynucleotide molecules translocating through the pore. The XPD helicase processively moves the polynucleotide through the pore, allowing complete sequencing of each individual molecule without requiring amplification to generate large volumes. This self-sufficient detection approach eliminates the time-consuming PCR amplification step entirely
Solution Approach 2:
The invention changes the detection parameter from optical/chemical signal requiring large quantities to electrical signal that can detect single molecules. By measuring current blockades as individual nucleotides pass through the nanopore, the system achieves sufficient signal strength without needing to amplify the polynucleotide, thereby eliminating both the time and cost of amplification while maintaining adequate signal for detection
3Measurement precision
If specialist fluorescent chemicals are used for signal detection, then nucleotide identity can be determined, but the cost and complexity of the system increases
Solution Approach 1:
The invention extracts and removes specialist fluorescent chemicals from the detection system. Instead of using fluorescently labeled nucleotides and complex optical detection equipment, the method uses unlabeled polynucleotides and detects nucleotide identity through characteristic electrical current blockades as each nucleotide passes through the nanopore, thereby simplifying the system while maintaining identification accuracy
Solution Approach 2:
The invention replaces the complex optical detection system (fluorescence excitation, emission filtering, photodetectors) with a simple electrical measurement system. The nanopore setup measures current blockades that occur when nucleotides translocate through the pore, with each nucleotide type producing a characteristic current signature. This electrical detection method is inherently simpler and more direct than the multi-component optical detection system required for fluorescent sequencing
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 rapid and cost-effective polynucleotide sequencing by using XPD helicases to control the movement of polynucleotides through pores, providing high signal-to-noise ratios and allowing for the identification of nucleotides at high salt concentrations, thus overcoming the limitations of existing technologies.
Implementation Method 1
an XPD helicase can control the movement of a polynucleotide through a pore especially when a potential, such as a voltage, is applied. The helicase is capable of moving a target polynucleotide in a controlled and stepwise fashion against or with the field resulting from the applied voltage
Implementation Method 2
When a potential is applied across a nanopore, there is a change in the current flow when an analyte, such as a nucleotide, resides transiently in the barrel for a certain period of time
Implementation Method 3
Nanopore detection of the nucleotide gives a current change of known signature and duration
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
The invention relates to a new method of characterising a target polynucleotide. The method uses a pore and an XPD helicase. The helicase controls the movement of the target polynucleotide through the pore.