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Effects of the components of Newcastle disease virus on the structural order of lipid assemblies
1Central Laboratory of Biophysics, Bulgarian Academy of Sciences, Sofia.
Abstract:
The membrane M-protein of Newcastle disease virus is localized directly beneath the lipid bilayer. Although this protein is the major constituent of the virus, its structural relationship to the lipid or to the other viral component hemagglutinin-neuraminidase, the so called HN-glycoprotein, is still unknown. The effects of either M-protein alone or both M-protein and HN-glycoprotein on the lipid assemblies in reconstituted liposomes were determined by differential polarized phase fluorometry, steady-state fluorescence anisotropy and emission lifetime measurements. It is demonstrated that the degree of rotation of fluorophores in reconstituted liposomes is restricted by the molecular packing of lipids in the bilayer and this in turn can be correlated with the structural order of the lipids in the membrane. The experimental results show that the structural order parameters calculated from the fluorescence measurements are strongly influenced by the presence of both M-protein and HN-glycoprotein in the lipid assemblies.
Insights
Newcastle disease virus membrane proteins, M-protein and HN-glycoprotein, influence lipid bilayer structure. Their presence alters lipid packing and structural order in reconstituted liposomes.
Area of Science:
- Virology
- Biochemistry
- Membrane Biophysics
Background:
- The Newcastle disease virus (NDV) membrane M-protein is a major viral component located beneath the lipid bilayer.
- The structural relationship between the M-protein, the HN-glycoprotein, and the viral lipid bilayer remains unclear.
Purpose of the Study:
- To investigate the impact of NDV M-protein and HN-glycoprotein on lipid assembly structure.
- To understand how these viral proteins affect lipid bilayer organization and dynamics.
Main Methods:
- Utilized reconstituted liposomes to model viral lipid environments.
- Employed fluorescence spectroscopy techniques: differential polarized phase fluorometry, steady-state fluorescence anisotropy, and emission lifetime measurements.
- Correlated fluorophore rotation restriction with lipid molecular packing and structural order.
Main Results:
- Demonstrated that lipid structural order parameters are significantly influenced by the presence of both M-protein and HN-glycoprotein.
- Showed that viral proteins restrict the rotational mobility of fluorophores within the liposomes.
- Established a correlation between restricted fluorophore rotation and enhanced molecular packing of lipids.
Conclusions:
- Both NDV M-protein and HN-glycoprotein play a crucial role in modulating the structural organization of the viral lipid bilayer.
- These viral proteins directly impact lipid packing and membrane structural order.
- Fluorescence measurements provide a sensitive method to assess viral protein-lipid interactions.