Effect of membrane protein on lipid bilayer structure: a spin-label electron spin resonance study of vesicular stomatitis virus

Abstract

Spin-label ESR was used to study the structure of the envelope of vesicular stomatitis virus (VSV). The lipid is organized in a bilayer structure. Proteolytic digestion of the spike-like glycoprotein projections on the outer surface of the virus particle increases the fluidity of the lipid bilayer. Since the lipid composition of the virion reflects the composition of the host plasma membrane and the protein composition is determined by the viral genome, VSV was grown in both MDBK [bovine kidney] and BHK21-F [hamster kidney] cells to determine the effect of a change in lipid composition on the structure of the lipid bilayer of VSV. The lipid bilayer of the virion was more rigid when derived from MDBK cells than from BHK21-F cells. Studies comparing spin-labeled intact cells and cell membrane fractions suggest that upon labeling the whole cell, the spin label probes the plasma membrane. The lipid bilayer of the plasma membrane is apparently much more fluid than that of the virion. The effect of membrane-associated protein on the structure of the lipid bilayer is discussed.