Low Fidelity Mutants in the O-Helix of Thermus aquaticus DNA Polymerase I

Low fidelity mutants in the O-helix of Thermus aquaticus DNA polymerase I.

We screened 67 mutants in the O-helix of Thermus aquaticus (Taq) DNA polymerase I (pol I) for altered fidelity of DNA synthesis. These mutants were obtained (Suzuki, M., Baskin, D., Hood, L., and Loeb, L. A. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 9670-9675) by substituting an oligonucleotide containing random sequences for codons 659-671, and selecting for complementation of a growth defect...

High fidelity DNA synthesis by the Thermus aquaticus DNA polymerase

We demonstrate that despite lacking a 3'----5' proofreading exonuclease, the Thermus aquaticus (Taq) DNA polymerase can catalyze highly accurate DNA synthesis in vitro. Under defined reaction conditions, the error rate per nucleotide polymerized at 70 degrees C can be as low as 10(-5) for base substitution errors and 10(-6) for frameshift errors. The frequency of mutations produced during a sin...

production of thermus aquaticus dna polymerase in escherichia coli

Purification of Thermus aquaticus DNA polymerase expressed in Escherichia coli.

DNA polymerase from Thermus aquaticus has become a common reagent in molecular biology because of its utility in DNA amplification and DNA sequencing protocols. A simplified method is described here for isolating the recombinant Taq enzyme after overproduction in Escherichia coli. Purification requires 8 to 10 h and entails heat treating and clearing the E. coli lysate, followed by precipitatio...

Cloning and Expression of Thermus Aquaticus DNA Polymerase Gene, Using a Thermo-Inducible Expression Vector

DNA polymerase gene from Thermus aquaticus strain YT1 was amplified using VENTTM DNA po-lymerase and cloned under the control of X.PR promoter and expression was induced by a shift in tern perature. The culture was then sonicated, and after centrifugation the lysate was treated with poly‌ethyleneimine followed by a salting-out step. Finally the protein was precipitated with ammonium sulfate and...