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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
Distribution and three-dimensional structure of AIDS virus envelope spikes
Ping Zhu1, Jun Liu, Julian Bess
1Department of Biological Science and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, USA.
Nature
|May 27, 2006
Summary
Researchers visualized the structure of AIDS retrovirus envelope spikes using cryo-electron microscopy. This provides insights into how human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infect cells, aiding vaccine development.
Area of Science:
- Virology
- Structural Biology
- Immunology
Background:
- Envelope glycoprotein (Env) spikes on AIDS retroviruses are crucial for host cell infection and are key targets for vaccine development.
- The native structure and distribution of Env spikes on virions remain poorly understood, despite known crystal structures of partial Env subunits.
Purpose of the Study:
- To define the ultrastructural details of native Env spikes on human immunodeficiency virus 1 (HIV-1) and simian immunodeficiency virus (SIV) virions.
- To understand the three-dimensional structure and distribution of Env spikes for potential vaccine design.
Main Methods:
- Cryoelectron microscopy tomography was applied to visualize native Env spikes on HIV-1 and SIV virions.
- Three-dimensional averaging techniques were used to reconstruct the spike structures.
Main Results:
- HIV-1 virions displayed approximately 14 spikes per particle, while SIV virions had approximately 73 spikes per particle, with some HIV-1 spikes showing clustering.
- The surface glycoprotein (gp120) 'head' of the trimeric SIV spike features a primary mass and two secondary lobes.
- The transmembrane glycoprotein 'stalk' of each trimer consists of three independent legs projecting tripod-like from the trimer head.
Conclusions:
- The study provides a detailed three-dimensional map of the Env spike structure, reconciling it with atomic structures.
- These findings offer insights into the orientation of Env spike structural elements and their functional implications for viral entry.
- Understanding the native Env spike structure is critical for developing effective AIDS retrovirus vaccines.
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