title: Human immunodeficiency virus (HIV) type 1 transframe protein can restore activity to a dimerization-deficient HIV protease variant.
abstract: The protease (PR) from human immunodeficiency virus (HIV) is essential for viral replication: this aspartyl protease, active only as a dimer, is responsible for cleavage of the viral polyprotein precursors (Gag and Gag-Pol), to release the functional mature proteins. In this work, we have studied the structure-function relationships of the HIV PR by combining a genetic test to detect proteolytic activity in Escherichia coli and a bacterial two-hybrid assay to analyze PR dimerization. We showed that a drug-resistant PR variant isolated from a patient receiving highly active antiretroviral therapy is impaired in its dimerization capability and, as a consequence, is proteolytically inactive. We further showed that the polypeptide regions adjacent to the PR coding sequence in the Gag-Pol polyprotein precursor, and in particular, the transframe polypeptide (TF), located at the N terminus of PR, can facilitate the dimerization of this variant PR and restore its enzymatic activity. We propose that the TF protein could help to compensate for folding and/or dimerization defects in PR arising from certain mutations within the PR coding sequence and might therefore function to buffer genetic variations in PR.
authors.affiliation: Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, CNRS URA 2185, Institut Pasteur, 75724 Paris Cedex 15, France. ndautin@pasteur.fr
authors.forename: Nathalie
authors.initials: N
authors.lastname: Dautin
authors.forename: Gouzel
authors.initials: G
authors.lastname: Karimova
authors.forename: Daniel
authors.initials: D
authors.lastname: Ladant
mesh_terms: D000595:Amino Acid Sequence; D023241:Antiretroviral Therapy, Highly Active; D019281:Dimerization; D024882:Drug Resistance, Viral; D004926:Escherichia coli / Q000235:genetics; D015685:Fusion Proteins, gag-pol / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014644:Genetic Variation; D016333:HIV Protease / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D020798:Two-Hybrid System Techniques
chemical_list: D015685:Fusion Proteins, gag-pol; D010455:Peptides; D011498:Protein Precursors; C476407:transframe polypeptide, human; D016333:HIV Protease