Mutant Taq Polymerase for High Salt PCR Amplification
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Solution Overview
Problem
Diagnostic and forensic PCR often experiences false-negative reactions or low sensitivity due to inhibitory substances, particularly high salt concentrations found in blood samples and body fluids, which interfere with DNA polymerase activity.
Innovation Solution
Development of mutant Taq polymerase with specific point mutations that enhance its stability and activity in high salt environments, allowing for efficient PCR amplification in blood, plasma, and other body fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild type Taq polymerase is used for PCR amplification, then the reaction works under standard conditions, but the sensitivity is reduced and false-negative reactions occur in high salt concentration samples such as blood and body fluids
Solution Approach 1:
The patent applies parameter changes by introducing specific amino acid substitutions (E39K, E189K, E230K, E507K, E520K, E537K, and D578R) into the Taq polymerase protein structure. These parameter changes at the molecular level modify the enzyme's properties to enhance its stability and activity in high salt concentrations, directly resolving the technical contradiction between maintaining reliable PCR amplification and overcoming the inhibitory effects of high salt environments in blood and body fluid samples.
2Measurement precision
If standard PCR conditions are used, then the procedure is simple, but the detection sensitivity is low in samples containing inhibitory substances
Solution Approach 1:
The patent applies local quality by making targeted amino acid substitutions at specific positions (E39K, E189K, E230K, E507K, E520K, E537K, D578R) within the Taq polymerase structure. Rather than fundamentally redesigning the entire enzyme, these localized modifications at critical residues enhance salt tolerance and detection sensitivity while maintaining the overall simplicity of the PCR procedure, thus resolving the contradiction between measurement precision and device complexity.
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 mutant Taq polymerase effectively amplifies DNA in samples with high salt concentrations, improving PCR sensitivity and reducing false-negative reactions.
Implementation Method 1
DNA polymerase-mediated primer elongation (usually performed at about 50-72° C.) to create new complementary amplicon strands
Implementation Method 2
successive rounds of heating at different temperatures to facilitate target DNA strand de-annealing (usually performed at about 90-99° C.)
Implementation Method 3
primer:target DNA strand annealing (usually performed at about 40-70° C.)
Data Source
AI summary
The invention includes a mutant Taq polymerase, which can effectively amplify a target sequence under conditions of salt concentration(s) similar to body fluids, including blood, serum or plasma preserved with sodium citrate. The mutant Taq polymerase, or a biologically active fragment thereof, has one or more substitutions differing from the wild type as shown in Table I.