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Updated: Aug 7, 2026

Rapid Screening of HIV Reverse Transcriptase and Integrase Inhibitors
Published on: April 9, 2014
Hypersusceptibility to substrate analogs conferred by mutations in human immunodeficiency virus type 1 reverse
Robert A Smith1, Donovan J Anderson, Bradley D Preston
1Department of Pathology, University of Washington, K-084 HSB, Box 357705, 1959 NE Pacific St., Seattle, 98195, USA. smithra@u.washington.edu
Mutations in HIV-1 reverse transcriptase motif B alter drug sensitivity. Specific changes confer broad resistance or hypersusceptibility to nucleoside and pyrophosphate analogs, impacting HIV-1 treatment strategies.
Area of Science:
- Virology
- Molecular Biology
- Drug Discovery
Background:
- Human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) possesses conserved structural motifs, including motif B.
- Motif B plays a crucial role in substrate specificity by interacting with nucleotides, the template strand, and active-site residues.
Purpose of the Study:
- To investigate the functional significance of motif B in HIV-1 RT.
- To identify specific amino acid residues within motif B that influence substrate analog sensitivity.
Main Methods:
- Random scanning mutagenesis was employed on 11 residues within motif B.
- Replication-competent mutants were screened for altered sensitivity to nucleoside analogs (lamivudine, zidovudine/AZT) and phosphonoformic acid (PFA).
Main Results:
- Single amino acid substitutions in motif B resulted in resistance to lamivudine and/or hypersusceptibility to AZT.
- Substitutions at residue Q151 led to increased sensitivity to multiple nucleoside analogs and hypersusceptibility to PFA.
- Some AZT-hypersusceptible mutants exhibited PFA resistance, mirroring clinical and in vitro selected variants.
Conclusions:
- Specific amino acid alterations in motif B confer broad-spectrum hypersusceptibility to substrate analog inhibitors.
- Motif B is critical for regulating interactions between RT and deoxynucleoside triphosphates throughout polymerization.
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