3′-Blocked Nucleotide Purification by Selective 3′-OH Polymerization
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Solution Overview
Problem
Existing nucleic acid sequencing methods are hindered by the interference of 3′-unblocked nucleotides, which cause errors in sequencing due to their ability to be polymerized rapidly by SBS polymerases without the need for a blocking group removal, leading to inaccurate sequence determination.
Innovation Solution
A method involving the use of a polishing polymerase to selectively polymerize and remove 3′-OH nucleotides from a mixture, followed by using an SBS polymerase to polymerize the 3′-blocked nucleotides, with the aid of temperature-controlled devices like cache manifolds to optimize conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If 3′-OH nucleotides are present in the solution, then the polymerization reaction can proceed rapidly, but sequencing errors increase due to inability to control incorporation rate
Solution Approach 1:
The patent removes 3′-OH nucleotides from the solution through selective polymerization using a polishing polymerase before the main sequencing reaction. This extraction of the harmful component (3′-OH nucleotides) eliminates their interference with controlled polymerization, allowing both high speed and high accuracy in the subsequent SBS reaction.
Solution Approach 2:
The patent performs a preliminary purification step using a polishing polymerase to selectively incorporate 3′-OH nucleotides and remove them from the solution before the main sequencing reaction. This preliminary action ensures that only 3′-blocked nucleotides remain, enabling controlled polymerization with both high speed and accuracy in the subsequent SBS reaction.
2Reliability
If polishing polymerase is used to selectively polymerize 3′-OH nucleotides, then sequencing accuracy improves, but process complexity increases
Solution Approach 1:
The patent employs a polishing polymerase that performs multiple functions: it selectively recognizes and incorporates 3′-OH nucleotides, and simultaneously removes them from the solution through controlled polymerization. This multi-functionality achieves purification and sequencing accuracy improvement without requiring separate complex purification apparatus.
Solution Approach 2:
The polishing polymerase automatically distinguishes between 3′-OH and 3′-blocked nucleotides based on their chemical properties, selectively incorporating only 3′-OH nucleotides into the polymer chain. This self-service mechanism eliminates the need for external complex separation devices, as the enzyme itself performs the purification function through its inherent specificity.
3Productivity
If temperature control is applied to optimize polymerization conditions, then polymerization efficiency increases, but equipment complexity increases
Solution Approach 1:
The patent employs dynamic temperature control during the polymerization process, adjusting temperature to optimize the activity of the polishing polymerase and SBS polymerase at different stages. This dynamic adjustment maximizes polymerization efficiency at each step without requiring complex equipment, as temperature is a simple physical parameter to control.
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 reduces the concentration of 3′-OH nucleotides relative to 3′-blocked nucleotides, minimizing sequencing errors and enabling accurate detection of sequence information.
Implementation Method 1
using the polishing polymerase and the template to selectively polymerize the 3′-OH nucleotides
Implementation Method 2
the polishing polymerase includes a thermostable polymerase... the solution is heated to a temperature of about 30-75° C.
Implementation Method 3
a cache manifold including an inner structure, an outer sleeve, and a spiral tube through which the solution flows, wherein at least one of the inner structure and the outer sleeve is heated
Implementation Method 4
the solution further includes yeast inorganic pyrophosphatase (YPP) to increase a rate at which 3′-OH nucleotides are polymerized
Data Source
AI summary
A method for purifying nucleotides is provided, that includes preparing a solution comprising (a) 3′-blocked nucleotides, (b) 3′-OH nucleotides, (c) a polishing polymerase, and (d) a template. The polishing polymerase and the template are used to selectively polymerize the 3′-OH nucleotides and thus reduce a concentration in the solution of the 3′-OH nucleotides relative to the 3′-blocked nucleotides.