Biophysical Characterization of p51 and p66 Monomers of HIV-1 Reverse Transcriptase with Their Inhibitors

Human immunodeficiency virus (HIV)-1 reverse transcriptase (HIV-1 RT) is responsible for the transcription of viral RNA genomes into DNA genomes and has become an important target for the treatment of acquired immune deficiency syndrome (AIDS). This study used biophysical techniques to characterize the HIV-1 RT structure, monomer forms, and the non-nucleoside reverse transcriptase inhibitors (NNRTIs) bound forms. Inactive p66(W401A) and p51(W401A) were selected as models to study the HIV-1 RT monomer structures. Nuclear magnetic resonance (NMR) spectroscopy revealed that the unliganded forms of p66(W401A) protein and p51(W401A) protein had similar conformation to each other in solution. The complexes of p66(W401A) or p51(W401A) with inhibitors showed similar conformations to p66 in the RT heterodimer bound to the NNRTIs. Furthermore, the results of paramagnetic relaxation enhancement (PRE)-assisted NMR revealed that the unliganded forms of the p66(W401A) and p51(W401A) conformations were different from the unliganded heterodimer, characterized by a greater distance between the fingers and thumb subdomains. Small-angle X-ray scattering (SAXS) experiments confirmed that p66(W401A) and p51(W401A) can bind with inhibitors, similar to the p66/p51 heterodimer. The findings of this study increase the structural knowledge base of HIV-1 RT monomers, which may be helpful in the future design of potent viral inhibitors.

Automated summary

This study characterized the structure and monomer forms of HIV-1 RT using biophysical techniques, and found that the unliganded monomers have different conformations compared to the complexes. Small-angle X-ray scattering experiments confirmed the binding of p66(W401A) and p51(W401A) with inhibitors.