Herpes simplex virus DNA-directed DNA polymerase (UL30) (UL30)

The Herpes simplex virus DNA-directed DNA polymerase is a critical enzyme for the replication of the double-stranded DNA genome of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) [1.2.1, 1.2.2]. Encoded by the UL30 gene, this catalytic subunit belongs to the Family B DNA polymerases and forms a highly processive holoenzyme when complexed with its accessory protein, UL42 [1.2.2, 1.3.5]. The enzyme possesses multiple catalytic activities, including 5'-3' DNA polymerization for genome synthesis and 3'-5' exonuclease proofreading to maintain high replication fidelity [1.1.1, 1.4.3]. It is the primary therapeutic target for most clinically approved anti-herpetic drugs, such as acyclovir and foscarnet [1.3.1, 1.4.3]. These drugs typically function as nucleoside analogs that cause premature chain termination or as pyrophosphate analogs that directly inhibit the enzyme's active site [1.4.1, 1.4.2]. Mutations in the UL30 gene are a significant cause of clinical resistance to these antiviral therapies, particularly in immunocompromised patients undergoing long-term treatment [1.3.2, 1.3.4].

Other names

UL30HSV DNA polymeraseDNA polymerase catalytic subunitPolpUL30

Nucleoside and nucleotide analogs (e.g., acyclovir, ganciclovir) are phosphorylated to their active triphosphate forms, which then compete with natural dNTPs for incorporation into the viral DNA strand by the polymerase, leading to chain termination or competitive inhibition [1.4.1, 1.4.2]. Pyrophosphate analogs like foscarnet directly inhibit the pyrophosphate binding site of the enzyme without requiring phosphorylation [1.3.2, 1.4.3].