High-fidelity amplification using a thermostable DNA polymerase isolated from Pyrococcus furiosus

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Thermostable DNA polymerases are crucial for amplifying DNA via polymerase chain reaction (PCR).
• The fidelity of DNA polymerases directly impacts the accuracy of PCR amplification products.
• Pyrococcus furiosus (Pfu) is a hyperthermophilic archaeon known to harbor robust enzymes.

Purpose of the Study:

• To isolate and characterize a thermostable DNA polymerase from P. furiosus with proofreading activity.
• To evaluate the fidelity of Pfu DNA polymerase in comparison to Taq DNA polymerase using a genetic assay during PCR.
• To quantify the error rates of both enzymes at specific gene loci.

Main Methods:

• Isolation of a thermostable DNA polymerase with 3'-to-5' exonuclease activity from P. furiosus.
• Development and application of a PCR fidelity assay utilizing the lacIOZ alpha gene system.
• Cloning and sequencing of amplified DNA fragments to detect mutations.
• Quantification of mutation frequencies and calculation of error rates per nucleotide.

Main Results:

• The Pfu DNA polymerase exhibits significant 3'-to-5' exonuclease (proofreading) activity.
• PCR amplification using Pfu DNA polymerase resulted in <10% of the mutations observed with Taq DNA polymerase.
• The error rate for Pfu DNA polymerase was determined to be 1.6 x 10(-6) per nucleotide.
• This represents a greater than tenfold improvement in fidelity compared to Taq DNA polymerase's error rate of 2.0 x 10(-5).

Conclusions:

• Pfu DNA polymerase is a highly accurate enzyme for PCR, owing to its proofreading capability.
• The fidelity of Pfu DNA polymerase significantly surpasses that of Taq DNA polymerase.
• This enhanced fidelity makes Pfu DNA polymerase a valuable tool for applications requiring high-accuracy DNA amplification.