Hepatitis B virus DNA polymerase and Human immunodeficiency virus type 1 reverse transcriptase (HBV Pol / HIV-1 RT)

Hepatitis B virus (HBV) DNA polymerase and Human immunodeficiency virus type 1 (HIV-1) reverse transcriptase are essential viral enzymes that facilitate the replication of their respective viruses. HBV DNA polymerase is a multi-functional protein (P protein) that includes terminal protein, spacer, reverse transcriptase, and RNase H domains, converting pregenomic RNA into DNA (UniProt: P03158). HIV-1 reverse transcriptase is a heterodimer responsible for converting the single-stranded viral RNA genome into double-stranded DNA for integration into the host genome (UniProt: P03366). These enzymes are the primary targets for nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs/NtRTIs), which are the backbone of antiretroviral and anti-HBV therapies. Drugs like tenofovir and lamivudine compete with natural deoxynucleotides for incorporation into the nascent DNA strand, leading to premature chain termination (PubChem). Effective inhibition of these targets reduces viral load, prevents liver damage in HBV, and halts immune system decline in HIV. However, long-term use is associated with risks such as nephrotoxicity and the development of resistance mutations that can compromise treatment efficacy. In patients co-infected with both viruses, these dual-acting agents are particularly critical for simultaneous management of both infections (NIH/StatPearls).

Other names

P proteinPolReverse transcriptaseHBV PolHIV-1 RTRNA-directed DNA polymerase

Nucleoside and nucleotide analogues act as competitive inhibitors of the viral polymerase/reverse transcriptase; they are incorporated into the growing DNA strand and cause premature chain termination due to the absence of a 3'-hydroxyl group.