φ29 DNA Polymerase Amplification with Tween 20 and Ammonium Salts
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Solution Overview
Problem
Current DNA amplification protocols using φ29 DNA polymerase are limited in their ability to amplify DNA from very small amounts, requiring significant improvements in specificity and yield to effectively process picogram or femtogram quantities of DNA.
Innovation Solution
The method involves a reaction mixture containing φ29 type DNA polymerase, polyoxyethylenated sorbitan monolaurate (Tween 20) at specific concentrations, an ammonium salt (such as ammonium sulfate or chloride), a buffer, magnesium chloride, and a primer, which significantly enhances the amplification of DNA from as low as 0.1 femtograms of plasmid DNA or 10 femtograms of genomic DNA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If standard DNA amplification protocols are used, then amplification can be performed with conventional DNA amounts, but the ability to amplify from very small amounts (picogram or femtogram quantities) is limited
Solution Approach 1:
The patent applies parameter changes by optimizing the reaction conditions including buffer composition (pH 7.5-8.5), magnesium chloride concentration (2-20 mM), nucleoside triphosphate concentrations (100-800 μM each), and incubation temperature (25-40°C). These parameter optimizations enable the φ29 DNA polymerase to achieve high amplification efficiency even with extremely low template amounts (0.1 fg plasmid DNA or 10 fg genomic DNA), resolving the contradiction between low input quantity and high productivity
Solution Approach 2:
The patent uses a primer as an intermediary that hybridizes to the template DNA and provides a starting point for polymerase extension. The primer enables the φ29 DNA polymerase to efficiently amplify even trace amounts of template DNA by providing a stable initiation site, thus mediating between the low template quantity and high amplification output
2Measurement precision
If DNA amplification is performed from very small amounts, then sensitivity is improved, but non-specific amplification increases
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: buffer pH (7.5-8.5), magnesium chloride concentration (2-20 mM), and incubation temperature (25-40°C). These optimized parameters create a specific reaction environment that favors specific primer-template binding and extension while suppressing non-specific interactions, thus achieving both high sensitivity and high specificity in amplification from low template amounts
Solution Approach 2:
The patent replaces complex multi-step purification and enrichment procedures with a simplified isothermal amplification system using φ29 DNA polymerase. This enzymatic system inherently provides high specificity through the polymerase's intrinsic properties (3'-5' exonuclease activity for proofreading, high processivity) while maintaining extreme sensitivity, eliminating the need for additional specificity-enhancing steps that would compromise sensitivity
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 prevents non-specific DNA amplification and allows for specific, high-yield amplification of DNA from extremely low template amounts, improving the amplification efficiency by several orders of magnitude compared to standard protocols, enabling the production of micrograms of DNA from as little as 0.1 femtogram of plasmid DNA.
Implementation Method 1
a φ29 type DNA polymerase, capable of catalyzing both the initiation of the replication and the elongation of the synthesized strand
Implementation Method 2
polyoxyethylenated sorbitan monolaurate, wherein the polyoxyethylenated sorbitan monolaurate is in a proportion between 0.006% and 0.05% of the total volume of the reaction
Implementation Method 3
an ammonium salt, wherein the ammonium salt is ammonium sulfate at a concentration between 30 mM and 60 mM, ammonium chloride at a concentration between 60 mM and 120 mM or ammonium acetate at a concentration between 60 mM and 120 mM
Implementation Method 4
magnesium chloride
Data Source
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AI summary
The present invention is encompassed within the biotechnology field. Specifically, it relates to a method for replicating, amplifying or sequencing a deoxyribonucleic acid with a φ29 type DNA polymerase and to a kit for carrying out said method.