Question

Thermostable 'Taq polymerase' enzyme used in PCR is isolated from :

• A. Agrobacterium tumifaciens
• B. Thermus aquaticus
• C. Bacillus thuringiensis
• D. Haemophilus influenzae

Answer 1

Answer:

B. Thermus aquaticus

• Taq polymerase is a thermostable DNA polymerase enzyme named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated.
• Discovery and Utility: It was discovered in 1965 by Thomas D. Brock. Its primary significance in molecular biology is its ability to withstand the high temperatures required for DNA denaturation during the Polymerase Chain Reaction (PCR) cycles.
• Characteristics:
  • It functions optimally at temperatures around 75°C to 80°C.
  • Unlike standard DNA polymerases which denature at high heat, Taq polymerase remains functional throughout the repeated heating and cooling cycles of PCR.
• Scientific Impact: The adoption of Taq polymerase in the 1980s revolutionized molecular biology by automating the PCR process, which previously required the addition of fresh enzyme after each denaturation step.
• Notable Fact: In 1989, Science magazine named Taq polymerase the first 'Molecule of the Year'.
• Other Thermostable Enzymes: Other commonly used thermostable polymerases in biotechnology include Pfu polymerase (isolated from Pyrococcus furiosus) and Vent polymerase (isolated from Thermococcus litoralis), which are often preferred for their proofreading activity.