Proteins of DNA Replication from Extreme Thermophiles: PCR and Beyond

Abstract

PCR remains one of the most versatile and widely used techniques in molecular biology, yet the capabilities of PCR seem rudimentary when compared to genome replication in living cells. Modifying Taq polymerase, or supplementing or replacing it with other proteins of thermophilic archaea or bacteria, has enhanced the functional properties of PCR and created other techniques with extended or complementary capabilities. The enhancements to PCR include increased fidelity, the ability to amplify damaged template, and tolerance of otherwise inhibitory substances in analytical samples, whereas the complementary techniques include whole-genome amplification, high-resolution genotyping, and improved performance of massively parallel sequencing. A tremendous functional diversity of thermostable DNA-replication enzymes is provided by (i) the native proteins of thermophiles currently in culture, (ii) those cloned from uncultivated thermophiles, and (iii) molecular engineering of clones obtained from both these sources. The extent and depth of this molecular diversity argues that the pace of technological innovation involving DNA synthesis at elevated temperatures will continue to accelerate.