Early attempts at the polymerase chain reaction (PCR) used E.coli DNA polymerase. This was replaced with DNA polymerase from thermus aquaticus (“Taq” polymerase). Which is the primary advantage in using this enzyme? (AIPG -09)
|A||It is cheaper than E.coli polymerase|
|B||Specificity is increased because nonspecific hybridization of primers does not occur|
|C||Use of Taq polymerase enables lower temperatures to be used.|
|D||Use of Taq polymerase results in fewer PCR cycles.|
a. DNA polymerase isolated from the hot springs thermophilic bacterium named T. aquaticus is essential for the PCR process because of its stability at high temperatures (95°C).
b. While the E. coli enzyme can be used, the enzyme itself becomes denatured, fewer cycles are possible, and nonspecific reactions occur because of hybridization of primers to nontarget DNA.
c. The use of Taq polymerase allows DNA copying at 72°C rather than 37°C, which further reduces nonspecific hybridization.