Viral DNA-directed DNA polymerase (vDNA pol)

Viral DNA-directed DNA polymerase is a critical enzyme responsible for the replication of the viral genome in DNA-containing viruses, such as members of the Herpesviridae and Hepadnaviridae families (StatPearls, 2023). It catalyzes the addition of deoxyribonucleotides to a growing DNA strand using a viral DNA template, ensuring the propagation of the virus within the host (UniProt, 2024). Because this enzyme is essential for viral survival and often differs significantly from host cell DNA polymerases in terms of substrate specificity and structure, it serves as a primary target for antiviral therapy (NCBI, 2022). Many clinical drugs, including nucleoside and nucleotide analogs like acyclovir and tenofovir, act as prodrugs that are phosphorylated and then incorporated into the viral DNA, causing chain termination (PubMed, 2021). Other inhibitors, such as foscarnet, directly block the pyrophosphate binding site of the enzyme without requiring phosphorylation (PubChem, 2024). In the case of Hepatitis B virus, the polymerase also possesses reverse transcriptase activity, making it a unique target within this class (LiverTox, 2023). Resistance to these therapies often arises through mutations in the polymerase gene, necessitating the monitoring of viral loads and genotypic markers in clinical practice (NIH, 2023). Therapeutic challenges include significant side effects such as nephrotoxicity and myelosuppression, which limit the use of certain potent inhibitors (StatPearls, 2023).

Other names

Viral DNA polymeraseDNA-dependent DNA polymerasevPolvDPP

Competitive inhibition of deoxyribonucleotide triphosphate (dNTP) binding and incorporation into the viral DNA strand, leading to premature chain termination, or direct inhibition of the pyrophosphate binding site.