Photocleavable Nucleotides for DNA Sequencing Read-Lengths
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Solution Overview
Problem
Current DNA sequencing technologies, such as cyclic reversible termination (CRT), face challenges in achieving long read-lengths due to poor enzyme kinetics and sequential modification of DNA duplexes, leading to inefficient deprotection and incorporation of reversible terminators, which limits the accuracy and speed of genomic sequencing.
Innovation Solution
Development of nucleotide and nucleoside compounds with photocleavable groups, such as 2-nitrobenzyl, that are well-tolerated by DNA polymerases, allowing for efficient termination and deprotection, enhancing cycle efficiency and read-lengths in DNA sequencing by incorporating fluorescent dyes for accurate base identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cyclic reversible termination (CRT) is used for DNA sequencing, then sequencing can be performed without gel electrophoresis, but poor enzyme kinetics and sequential modification of DNA duplexes lead to inefficient deprotection and incorporation, limiting read-lengths
Solution Approach 1:
The patent modifies the chemical structure of the terminating moiety in reversible terminator nucleotides by replacing traditional 3'-O-blocking groups with alternative photocleavable groups. This structural parameter change improves enzyme kinetics and deprotection efficiency, thereby extending read-lengths while maintaining the CRT methodology's operational simplicity
Solution Approach 2:
The patent introduces modified photocleavable protecting groups as intermediaries between the nucleotide base and the DNA polymerase enzyme. These intermediary groups facilitate more efficient enzyme recognition and incorporation, while also enabling improved deprotection characteristics that extend read-lengths without compromising the cyclic reversible termination process
2Manufacturing precision
If traditional photocleavable groups are used in reversible terminators, then termination can be achieved, but poor enzyme kinetics and sequential modification reduce cycle efficiency and limit read-lengths
Solution Approach 1:
The patent systematically varies parameters of the photocleavable protecting groups, including substitution patterns on the aromatic ring and linker arm lengths. These parameter optimizations maintain precise chain termination while dramatically improving deprotection efficiency and reducing sequential modification effects, thereby increasing cycle efficiency and productivity
Solution Approach 2:
The patent employs composite structures combining modified photocleavable groups with fluorescent dyes in the reversible terminator nucleotides. This composite design allows the terminating functionality to be maintained while the modified photogroup enhances overall molecule performance through improved enzyme kinetics and deprotection characteristics, increasing cycle efficiency
3Measurement precision
If sequential modification of DNA duplexes occurs during CRT, then base identification can be achieved, but the sequential nature of modification reduces deprotection efficiency and limits read-lengths
Solution Approach 1:
The patent modifies the photocleavable group parameters to enable simultaneous or near-simultaneous deprotection of multiple bases rather than sequential deprotection. This parameter optimization maintains accurate base identification through fluorescent detection while dramatically extending the effective read-length by eliminating the time-consuming sequential deprotection bottleneck
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
The use of these compounds improves cycle efficiency, enabling longer read-lengths and faster, more accurate DNA sequencing, facilitating rapid whole genome sequencing and identification of polymorphisms, thereby reducing sequencing costs and time.
Implementation Method 1
nucleotide and nucleoside compounds with photocleavable groups, such as 2-nitrobenzyl
Implementation Method 2
incorporating fluorescent dyes for accurate base identification
Data Source
AI summary
Provided are novel nucleotides, nucleoside, and their derivatives described herein, that can be used in DNA sequencing technology and other types of DNA analysis. In one embodiment, the nucleotide or nucleoside with an unprotected 3′-OH group is derivatized at the nucleobase to include a fluorescent dye attached via a linker to a photocleavable terminating group. The photocleavable-fluorescent group is designed to terminate DNA synthesis as well as be cleaved so that DNA oligomers can be sequenced efficiently in a parallel format. The design of such rapidly cleavable fluorescent groups on nucleotides and nucleosides can enhance the speed and accuracy of sequencing of large oligomers of DNA in parallel, to allow rapid whole genome sequencing, and the identification of polymorphisms and other valuable genetic information, as well as allowing further manipulation and analysis of nucleic acid molecules in their native state following cleavage of the fluorescent group.