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Structure of equine infectious anemia virus matrix protein
Hideki Hatanaka1, Oleg Iourin, Zihe Rao
1Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom.
Abstract:
The Gag polyprotein is key to the budding of retroviruses from host cells and is cleaved upon virion maturation, the N-terminal membrane-binding domain forming the matrix protein (MA). The 2.8-A resolution crystal structure of MA of equine infectious anemia virus (EIAV), a lentivirus, reveals that, despite showing no sequence similarity, more than half of the molecule can be superimposed on the MAs of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV). However, unlike the structures formed by HIV-1 and SIV MAs, the oligomerization state observed is not trimeric. We discuss the potential of this molecule for membrane binding in the light of conformational differences between EIAV MA and HIV or SIV MA.
Insights
The matrix protein (MA) of equine infectious anemia virus (EIAV) shares structural similarities with HIV-1 and SIV MA, but differs in its oligomerization state, impacting membrane binding. This study reveals key conformational differences for lentivirus assembly.
Area of Science:
- Virology
- Structural Biology
- Biochemistry
Background:
- The Gag polyprotein is essential for retroviral budding and virion maturation.
- The N-terminal matrix protein (MA) domain mediates membrane binding.
- Equine infectious anemia virus (EIAV) is a lentivirus with implications for understanding retroviral replication.
Purpose of the Study:
- To determine the crystal structure of EIAV MA.
- To compare the structure of EIAV MA with MAs from other lentiviruses like HIV-1 and SIV.
- To investigate the implications of structural differences for membrane binding and viral assembly.
Main Methods:
- X-ray crystallography at 2.8-A resolution.
- Structural comparison and superimposition of MA proteins.
- Analysis of oligomerization states.
Main Results:
- The crystal structure of EIAV MA was determined at 2.8-A resolution.
- Over half of the EIAV MA molecule could be superimposed onto HIV-1 and SIV MAs, despite no sequence similarity.
- EIAV MA did not form a trimeric structure, unlike HIV-1 and SIV MAs.
Conclusions:
- EIAV MA shares conserved structural features with other lentiviral MAs, suggesting a common mechanism for membrane interaction.
- The non-trimeric oligomerization state of EIAV MA represents a significant difference from HIV-1 and SIV MA.
- Conformational variations in EIAV MA may influence its membrane-binding properties and role in viral assembly, offering insights into lentivirus diversity.