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Determination of Molecular Structures of HIV Envelope Glycoproteins using Cryo-Electron Tomography and Automated Sub-tomogram Averaging
Published on: December 1, 2011
Atomic structure of the ectodomain from HIV-1 gp41
W Weissenhorn1, A Dessen, S C Harrison
1Laboratory of Molecular Medicine, The Children's Hospital, Boston, Massachusetts 02215, USA.
Nature
|May 22, 1997
Summary
Structural analysis of the HIV-1 gp41 ectodomain reveals a triple-stranded alpha-helical coiled coil core. This structure, determined by X-ray crystallography, suggests a common viral membrane fusion mechanism.
Area of Science:
- Structural Biology
- Virology
- Molecular Biology
Background:
- Human Immunodeficiency Virus type 1 (HIV-1) entry into host cells is mediated by the envelope glycoprotein complex gp120/gp41.
- The gp120/gp41 complex undergoes conformational changes upon binding to CD4 and co-receptors, initiating membrane fusion.
Purpose of the Study:
- To determine the three-dimensional structure of a protease-resistant fragment of the HIV-1 gp41 ectodomain.
- To elucidate the structural basis for viral membrane fusion.
Main Methods:
- X-ray crystallography was employed to determine the structure of the gp41 ectodomain.
- The gp41 ectodomain was solubilized using a trimeric GCN4 coiled coil in place of the fusion peptide.
Main Results:
- The core structure of the gp41 ectodomain fragment is an extended, triple-stranded alpha-helical coiled coil.
- The amino terminus is located at the tip of the coiled coil.
- A carboxy-terminal alpha-helix packs in reverse against the coiled coil, bringing termini together.
Conclusions:
- The determined structure provides insights into the mechanism of HIV-1 membrane fusion.
- Structural similarities with other viral fusion proteins suggest a conserved fusion initiation mechanism across different viruses.
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