Human immunodeficiency virus type 1 reverse transcriptase p51 subunit (HIV-1 RT p51)

HIV-1 reverse transcriptase (RT) is a heterodimeric enzyme essential for the replication of the human immunodeficiency virus type 1, responsible for converting the viral RNA genome into double-stranded DNA [1, 3]. The enzyme is composed of two subunits: the 66 kDa (p66) subunit and the 51 kDa (p51) subunit [2]. The p51 monomer is a truncated version of p66, produced by the viral protease's cleavage of the RNase H domain [1, 4]. Although the p51 subunit lacks catalytic activity on its own, it provides the necessary structural framework for the p66 subunit, which contains the active sites for polymerase and RNase H functions [3, 4]. Most clinical reverse transcriptase inhibitors (RTIs), including nucleoside (NRTIs) and non-nucleoside (NNRTIs) classes, target the heterodimeric complex, with p51 contributing to the formation of the NNRTI binding pocket [4, 5]. Research also explores the p51 subunit as a target for dimerization inhibitors that prevent the formation of the functional p66/p51 heterodimer [4]. The p51 subunit's conformation is significantly different from its p66 counterpart despite having an identical sequence for the first 440 amino acids, highlighting its structural plasticity [2, 3]. This unique role makes it a critical component of the viral replication machinery and a subject of interest for overcoming drug resistance [4].

Other names

p51 subunitHIV-1 RT p51 monomerReverse transcriptase p51Pol polyprotein p51

Inhibition of viral DNA synthesis through competitive chain termination (NRTIs) or allosteric modulation of the polymerase active site (NNRTIs); potential disruption of subunit dimerization [4, 5].