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Updated: May 16, 2026

Visualization of HIV-1 Gag Binding to Giant Unilamellar Vesicle (GUV) Membranes
Published on: July 28, 2016
HIV-1 p6 - a structured to flexible multifunctional membrane-interacting protein
Sara Marie Øie Solbak1, Tove Ragna Reksten, Friedrich Hahn
1Department of Chemistry and Centre for Pharmacy, University of Bergen, N-5007 Bergen, Norway.
The human immunodeficiency virus type 1 (HIV-1) p6 protein has a defined helical structure in hydrophobic environments, crucial for viral assembly. Phosphorylation enhances its membrane interaction, modulating Gag polyprotein binding.
Area of Science:
- Virology
- Structural Biology
- Biochemistry
Background:
- The human immunodeficiency virus type 1 (HIV-1) p6 protein is essential for infectious virus formation.
- p6 is implicated in interactions with cellular and viral partners, primarily near the cytoplasmic membrane.
- Previously, p6 was thought to have a random structure in aqueous solution.
Purpose of the Study:
- To elucidate the structure of the HIV-1 p6 protein in a hydrophobic environment.
- To investigate the interaction of p6 with model cytoplasmic membranes.
- To determine the effect of phosphorylation on p6-membrane interactions and its role in HIV-1 Gag modulation.
Main Methods:
- Nuclear magnetic resonance (NMR) spectroscopy in dodecylphosphocholine (DPC) micelles to determine p6 structure.
- Surface plasmon resonance (SPR) spectroscopy to analyze p6-membrane interactions.
- Site-directed mutagenesis (Ser40 to Phe) to assess phosphorylation effects.
Main Results:
- HIV-1 p6 exhibits a defined structure with N- and C-terminal helical domains in micelle solution, representing a genuine structural feature in hydrophobic environments.
- p6 directly interacts with model cytoplasmic membranes via both its N- and C-terminal regions.
- Phosphorylation of Ser-40 significantly amplifies p6 membrane interaction, suggesting binding to polar head groups, and influences HIV-1 Gag membrane association.
Conclusions:
- The HIV-1 p6 protein possesses a defined helical structure in hydrophobic environments, contrary to previous assumptions.
- p6's interaction with the cytoplasmic membrane is modulated by phosphorylation at Ser-40.
- These findings highlight p6's role in regulating the membrane association of the HIV-1 Gag polyprotein, impacting viral assembly.
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