Because there are a number of different methods that can be used to determine the fidelity of a given polymerase, it is difficult to compare the values obtained from one study to values obtained from another. But the range of published error rates for standard
taq polymerases is between 1.1 x 10
-4 to 8.9 x 10
-5 errors/base pair. Although for most applications absolute fidelity is not necessary, there are times when it is important. Vent
R® DNA Polymerase from New England Biolabs is a high-fidelity, thermophilic DNA polymerase that can be used for those occasions when it is important.
The high-fidelity of VentR® is derived in part from its integral 3’-5’ proofreading exonuclease activity. The product is supplied with 10X reaction buffer as well as a 100 mM MgSO4 stock solution. The 100 mM MgSO4 is provided so that the level of magnesium in the PCR reaction can be optimised. According to the literature that accompanies the product, VentR® is produced as a recombinant protein in E.coli. The Vent DNA Polymerase gene was isolated from the archae Thermococcus litoralis, which was originally obtained from a submarine thermal vent and is capable of growth at temperatures as high as 98oC. As a result, VentR® retains greater than 90% activity after a one hour incubation at 95oC.
For some time now I have been using this enzyme several times per week for my PCR reactions. I have amplified both short fragments (<1000 bp) as well as long fragments (<3000 bp) and have never had any problems with either. I also have never had to optimise the MgSO4 concentration in the reaction mixture - the amount of magnesium in the reaction buffer (2 mM) has worked well for all of my reactions. Best of all, I have, on several occasions, sequenced my PCR products and have not found any errors. The VentR® DNA Polymerase can be stored at -20˚C for several months without loss of activity.
In my hands, the VentR® DNA Polymerase has been an ideal polymerase. It has consistently given me good results in that it required a minimum of time for optimisation and it yields product that contains a minimum of error.
Fulvio Reggiori, Ph.D.
Post-Doctoral Fellow
MRC Laboratory of Molecular Biology
Cambridge, UK