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Crystal structures of the trimeric human immunodeficiency virus type 1 matrix protein: implications for membrane
C P Hill1, D Worthylake, D P Bancroft
1Department of Biochemistry, University of Utah, Salt Lake City, 84132, USA.
Abstract:
The human immunodeficiency virus type 1 (HIV-1) matrix protein forms a structural shell associated with the inner viral membrane and performs other essential functions throughout the viral life cycle. The crystal structure of the HIV-1 matrix protein, determined at 2.3 angstrom resolution, reveals that individual matrix molecules are composed of five major helices capped by a three-stranded mixed beta-sheet. Unexpectedly, the protein assembles into a trimer in three different crystal lattices, burying 1880 angstrom2 of accessible surface area at the trimer interfaces. Trimerization appears to create a large, bipartite membrane binding surface in which exposed basic residues could cooperate with the N-terminal myristoyl groups to anchor the protein on the acidic inner membrane of the virus.
Insights
The human immunodeficiency virus type 1 (HIV-1) matrix protein unexpectedly forms trimers. This trimerization creates a surface that may help anchor the protein to the virus's inner membrane.
Area of Science:
- Structural biology
- Virology
- Molecular biology
Background:
- The human immunodeficiency virus type 1 (HIV-1) matrix protein is crucial for viral structure and function.
- It associates with the inner viral membrane and plays roles throughout the viral life cycle.
Purpose of the Study:
- To determine the crystal structure of the HIV-1 matrix protein.
- To investigate the protein's assembly and potential membrane-binding mechanisms.
Main Methods:
- X-ray crystallography at 2.3 angstrom resolution.
Main Results:
- The HIV-1 matrix protein structure consists of five helices and a three-stranded beta-sheet.
- The protein unexpectedly self-assembles into trimers in crystal structures.
- Trimerization buries significant surface area and forms a bipartite membrane-binding surface.
Conclusions:
- The trimeric assembly of the HIV-1 matrix protein is a key structural feature.
- This trimerization likely facilitates anchoring to the virus's acidic inner membrane via basic residues and myristoyl groups.