If you are working with Taq DNA polymerase and want to impro

If you are working with Taq DNA polymerase and want to improve the processivity and fidelity of the enzyme, what kind of modifications might you try to engineer? Explain how your modifications would increase processivity and fidelity (be clear about which you are discussing).

Solution

Taq DNA Polymerase is a thermos-stable enzyme isolated from the thermophilic bacterium Thermus aquaticus. The recombinant form of this enzyme is expressed in E. coli. However, to increase proccessivity of Taq DNA polymerase, modification through changing the codons around the N-terminal region from the original gene to the AT-type or the optimal codons. Such manipulations, if found to improve the production of Taq polymerase more than 10-fold. However, in some study depict that, the codon usage of the initiation region is more critical factor than AT content of the gene sequence for overproduction of the Taq polymerase. In some cases, the frequency of AGG or AGA for arginine is found to be 10-20 fold lower than that of CGT. Conversion of the second codon for arginine to CGT may be effective for increasing translation level. Such conversion along with lower concentrations of dNTPs may increase both the specificity and fidelity.