Thermus aquaticus

Thermus aquaticus is a thermophilic bacterium isolated from a Yellowstone hot spring. Its heat-stable DNA polymerase made repeated high-temperature DNA amplification practical.

Taq polymerase: A heat-stable DNA-copying enzyme originally isolated from Thermus aquaticus. This enzyme is the bacterium’s best-known contribution to molecular biology.
Thermostability: The ability of a molecule or biological structure to retain function at elevated temperatures. Taq polymerase remains active through temperatures that denature many other DNA polymerases.
Thomas D. Brock: An American microbiologist whose research helped establish the study of life in hot springs. Brock and Hudson Freeze reported the isolation of Thermus aquaticus in 1969.
Klenow fragment: A large fragment of Escherichia coli DNA polymerase I that retains polymerase activity but lacks its 5′-to-3′ exonuclease activity. Unlike Taq polymerase, it is heat-sensitive and must be replenished during early PCR protocols.
Polymerase chain reaction: A laboratory method that amplifies selected DNA sequences through repeated cycles of heating and cooling. Taq polymerase lets PCR withstand the repeated high-temperature steps without enzyme replacement.
DNA replication: The cellular process of copying DNA before cell division. Taq polymerase performs a laboratory version of the DNA-synthesis chemistry used in replication.
Yellowstone National Park: A United States national park known for geothermal features, including hot springs and geysers. The bacterium was first isolated from a hot spring there.
Pfu polymerase: A thermostable DNA polymerase from the archaeon Pyrococcus furiosus with proofreading activity. Pfu offers greater copying accuracy than Taq, but generally extends DNA more slowly.
Real-time polymerase chain reaction: A PCR method that tracks DNA amplification during each cycle using fluorescence. Taq-based amplification underlies many real-time PCR assays.
DNA polymerase I: A bacterial enzyme involved in DNA synthesis and repair, including removal and replacement of nucleotides. Taq polymerase is related to bacterial DNA polymerase I and shares its DNA-synthesis role.

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ExtremophileBroader topic: It illustrates how a hot-spring organism yielded a widely used laboratory enzyme.