Palaeococcus helgesonii DNA Polymerase Thermostability
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Solution Overview
Problem
Current DNA polymerases used in thermocycling amplification reactions, such as PCR, often require high optimal growth temperatures and are derived from hyperthermophilic euryarchaeota like Pyrococcus and Thermococcus, limiting their applicability and availability.
Innovation Solution
A novel thermostable DNA polymerase is isolated from the Palaeococcus genus, which diverged before Thermococcus and Pyrococcus, exhibiting suitable thermostability for thermocycling amplification reactions despite an optimum growth temperature of 80°C, with a polypeptide having at least 79% identity to the Palaeococcus helgesonii DNA polymerase sequence, enabling its use in PCR and other nucleic acid amplification reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If DNA polymerases are derived from hyperthermophilic euryarchaeota (Pyrococcus and Thermococcus genera), then thermostability for thermocycling amplification reactions is improved, but the diversity and availability of polymerase sources are limited
Solution Approach 1:
The patent segments the archaeal domain into distinct genera (Pyrococcus, Thermococcus, and now Palaeococcus), systematically exploring different evolutionary lineages to discover novel polymerase sources. This segmentation allows independent characterization of each genus's polymerase properties without being constrained by previous limitations to only two genera.
Solution Approach 2:
Instead of only searching for polymerases from the most extreme hyperthermophiles (optimum growth temperatures of 95-100°C), the patent inverts the approach by examining organisms with lower optimum growth temperatures (80°C for Palaeococcus helgesonii). This inversion reveals that thermostability for PCR applications does not require the highest growth temperatures, thereby expanding the search space to include previously overlooked organisms.
2Temperature
If DNA polymerases are isolated from organisms with high optimum growth temperatures, then thermostability is improved, but the enzyme may lack optimal activity at lower thermocycling temperatures
Solution Approach 1:
The patent changes the parameter of optimum growth temperature selection, moving from the conventional approach of using organisms with 95-100°C optimum temperatures to organisms with 80°C optimum temperatures. This parameter change allows the polymerase to maintain both thermostability for PCR conditions and optimal activity at standard thermocycling temperatures, as demonstrated by the Palaeococcus helgesonii polymerase which shows high activity in PCR reactions.
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 Palaeococcus-derived DNA polymerase demonstrates high fidelity and stability in thermocycling amplification reactions, maintaining activity at high temperatures, making it suitable for PCR and other applications, even though the organism's optimal growth temperature is lower than traditional sources, thus expanding the range of thermostable polymerases available.
Implementation Method 1
DNA polymerases are enzymes involved in vivo in DNA repair and replication, but have become an important in vitro diagnostic and analytical tool for the molecular biologist
Implementation Method 2
several DNA polymerases obtained from thermophilic bacteria have been found to be thermostable, retaining polymerase activity at between 45°C to 100°C, depending on the polymerase
Data Source
Figure 1~2
Figure 3
AI summary
There is provided a polypeptide having thermostable DNA polymerase activity and comprising or consisting of an amino acid sequence with at least 78% identity to Palaeococcus helgesonii DNA polymerase shown in SEQ ID NO: 1 or SEQ ID NO:39.