DNAPol

DNAPol, short for DNA polymerase, is a broad term for a family of enzymes that synthesize DNA. These enzymes use a DNA template and a primer to catalyze the formation of phosphodiester bonds, extending the 3' end of a growing strand. Most DNAPols require divalent metal ions and operate in a 5' to 3' direction. Many possess a 3' to 5' exonuclease activity that provides proofreading, increasing fidelity.

DNAPols are categorized by function and phylogeny. Replicative polymerases such as bacterial DNA Pol III and eukaryotic Pol δ and Pol ε carry out bulk genome replication, while specialized polymerases handle primer processing (Pol I in bacteria) and mitochondrial replication (Pol γ in eukaryotes). Eukaryotes use Pol α to initiate synthesis with primase, followed by Pol δ or Pol ε for elongation. Translesion synthesis polymerases (e.g., Pol η, ι, κ and Rev1) enable synthesis across damaged bases, often with reduced fidelity.

Structurally, DNAPols share a conserved hand-like architecture with fingers, palm and thumb domains forming the active site. The catalytic core coordinates metal ions at the two-metal mechanism that drives nucleotide incorporation. Processivity is enhanced by sliding clamps (PCNA in eukaryotes, the β-clamp in bacteria) and clamp loaders that load the clamp onto DNA.

DNAPols play essential roles in DNA replication, repair, and recombination. Their activities are tightly regulated to prevent mutations, and defects in certain human DNAPols are associated with genomic instability and disease.

Biotechnologically, DNAPols are used in PCR, DNA sequencing, and DNA manufacturing. Thermostable variants, such as Taq polymerase, enable rapid amplification, while high-fidelity enzymes like Pfu and Phusion reduce error rates.