Using Heat-Resistant Enzymes to Read DNA Sequences Faster

This patent describes using a heat-stable enzyme from a bacterium that lives in hot springs to make the process of reading DNA code much more reliable and efficient.

What it covers

The patent improves the Sanger sequencing method, which reads DNA by stopping the building process at specific points using special molecules called dideoxynucleotides. Previously, researchers used enzymes that broke down at high temperatures, causing errors and incomplete readings. By using DNA polymerase from Thermus aquaticus (Taq), an organism that thrives in boiling water, the reaction can be performed at higher temperatures. This helps the DNA strands stay open and prevents them from tangling, leading to much clearer and more accurate results.

What it doesn't cover

• —Does not cover the fundamental Sanger sequencing method itself, only the use of Taq polymerase within it.
• —Does not cover the discovery of the Thermus aquaticus organism.
• —Does not cover sequencing methods that do not use dideoxynucleotide chain termination.
• —Does not cover the use of DNA polymerases derived from organisms other than Thermus aquaticus.

The clever bit

The inventors realized that the heat-stability of the Taq enzyme, originally prized for PCR, was the perfect solution to the 'secondary structure' problem in DNA sequencing, where DNA strands fold onto themselves and block the reading process.

Why it matters

This innovation was a critical step in the automation of DNA sequencing, which eventually enabled the Human Genome Project. By making the sequencing reaction robust enough to withstand high temperatures, it allowed scientists to read longer and more complex stretches of DNA without the frequent failures that plagued earlier methods.

Real-world examples

• 1.Standard Sanger sequencing protocols used in clinical diagnostics
• 2.Automated capillary electrophoresis DNA sequencers
• 3.Molecular biology research kits for gene mapping