Difference Between Phusion and Taq Polymerase

Key Difference – Phusion vs Taq Polymerase
 

DNA polymerases are widely used enzymes in molecular biology techniques and are also naturally present in all organisms that undergo DNA replication. They are the key polymerizing enzymes that involve during replication. DNA polymerase is capable of adding nucleotides to the free 3’ end of the DNA strand thereby causing the extension of a new strand. At present, due to the developments of molecular biology in disease diagnostics and industrial applications, it is important to manufacture polymerases having various beneficial properties. This increases the accuracy of the method and makes it a more rapid technique. Phusion and Taq polymerase are two commercially produced thermostable polymerase enzymes that are used in special molecular applications. Phusion is a DNA polymerase isolated from Pyrococcus furiosus and is mainly used in cloning experiments to increase the fidelity. Taq DNA Polymerase is the standard DNA polymerase used in the Polymerase Chain Reaction (PCR), and it is isolated from the thermostable bacterium; Thermus aquaticus. The key difference between the two enzymes is the source microorganism. Phusion is isolated from the extremophile, Pyrococcus furiosus whereas, Taq polymerase is isolated from the thermophile, Thermus aquaticus.

CONTENTS

1. Overview and Key Difference
2. What is Phusion
3. What is Taq Polymerase
4. Similarities Between Phusion and Taq Polymerase
5. Side by Side Comparison – Phusion vs Taq Polymerase in Tabular Form
6. Summary

What is Phusion?

Phusion DNA polymerase is a novel polymerase that is manufactured by isolating the enzyme from Pyrococcus furiosus, which is an extremophilic Archaea. These microbes reside in extremely high-temperature conditions, thereby making the polymerase a highly heat-stable polymerase. Phusion polymerase is used to obtain extreme fidelity over the conventional thermostable polymerase; Taq polymerase. Phusion polymerase is capable of amplifying long templates up to 7.5kb of genomic DNA. The optimal polymerization capacity of Phusion polymerase is at 72⁰ C. Phusion is also used in cloning products for sequencing, expression analysis and mutation analysis.

Phusion DNA polymerase has the 3’ – 5’ exonuclease activity. This allows proofreading of the newly synthesized strand after the synthesis. Hence, the  nucleotide mismatches are easily be repaired. Thus, it has a lesser error rate. Overall advantages of Phusion polymerase are;

• Extreme Fidelity
• High Speed and reduced extension time
• Robust Reactions and requires minimal optimization
• High Yield

Figure 01: Phusion

The main disadvantage of Phusion polymerase is that it is inhibited in the presence of deoxyuridine triphosphate (dUTP). When dUTPs are accumulated in the reaction mixture, it may inhibit the actions of Phusion polymerase. This is prevented by treating the reaction mixture with dUTPase prior to adding the enzyme. At present, a dUTP resistant variant of Phusion polymerase known as Pfu Turbo is used instead of Phusion polymerase as a remedy to this problem.

What is Taq Polymerase?

Taq DNA polymerase invention has revolutionized the field of molecular biology. It solved a major problem in DNA amplification. Taq DNA polymerase is a heat stable polymerase enzyme extracted and isolated from the thermophilic bacterium, Thermus aquaticus. The discovery of this enzymes leads to the development of the PCR. This enzyme has allowed the use of polymerase chain reaction in DNA amplification instead of conventional laborious cloning techniques. PCR is now used in molecular diagnostics, agricultural and industrial fields with many new variations added to the technique.

Figure 02: Taq Polymerase

Taq DNA polymerase functions at the optimal temperature range between 72⁰C – 80⁰C. Taq DNA polymerase requires a co-factor; magnesium for its function. Taq polymerase does not have the 3’ – 5’ proofreading ability, therefore, the error rate of Taq DNA polymerase is high in comparison to more newer types of DNA polymerases such as Phusion polymerase etc. But, the popularity of Taq DNA polymerase remains the same across the world of science due to the convenience and the flexibility of the enzyme.

What are the Similarities Between Phusion and Taq polymerase?

• Both Phusion and Taq polymerase enzymes are polymerizing enzymes that are capable of adding nucleotides to the 3’ free end of the DNA strand.
• Both Phusion and Taq polymerases require a primer sequence to initiate polymerization.
• Both Phusion and Taq polymerases are heat stable.
• Both Phusion and Taq polymerases are used in PCR mechanisms to amplify DNA.
• When adding the polymerase to the reaction mixture, both Phusion and Taq polymerases are added last to ensure the efficiency of the enzyme.
• Both Phusion and Taq polymerases are commercially synthesized for molecular biology experimental purposes.
• Both Phusion and Taq polymerases require a cofactor to complete its function.

What is the Difference Between Phusion and Taq Polymerase?

Summary – Phusion vs Taq polymerase 

Phusion and Taq DNA polymerase are two heat stable polymerases that are used in PCR techniques. Phusion is a polymerase isolated from the extremophile, Pyrococcus furiosus whereas, Taq is isolated from the thermostable bacteria Thermus aquaticus. Taq DNA polymerase discovery leads to the PCR invention. Phusion has many advantages over Taq that has made Phusion a better option in producing high fidelity DNA. However, Taq polymerase is still used as the standard polymerase enzyme in PCR. This is the difference between Phusion and Taq polymerase.

Reference:

1.Biolabs, New England. “Taq DNA Polymerases.” New England Biolabs: Reagents for the Life Sciences Industry. Available here  
2.“Phusion DNA Polymerase.” New England Biolabs. Available here 

Image Courtesy:

1.’GAM illustrated by Nivin Nasri’By NivinN – Own work, (CC BY-SA 4.0) via Commons Wikimedia  
2.’Taq’By Adenosine – Own work, (CC BY-SA 3.0) via Commons Wikimedia 

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