Investigation about the surface structure of some viruses by the freeze-etching and freeze-drying methods.

An electronmicroscopic study of a suspension of Venezuelan equine encephalomyelitis (VEE) virus by freeze-drying and freeze-etching methods showed that glycoprotein peplomers are located on the surface of the lipoprotein shell. These peplomers are trimeric in shape and form a regular icosahedral surface lattice corresponding to T = 4. The modes of glycoproteins clustering for the two clones of VEE are different. Venezuelan equine encephalomyelitis (VEE) virus belongs to the alpha-viruses of the toga-virus family. Virions of VEE virus have the icosahedral nucleocapsid surrounded by a lipoprotein envelope (peplos) and contain single-stranded RNA. During budding, alpha-virus nucleocapsid acquires a host cell lipid membrane in which virus specific glycoproteins are built in (Bonsdorff et al. 1975, Harrison et al. 1974). Earlier the surface peplomer clustering was investigated only for the sindbis virus (Bonsdorff et al. 1975, Bonsdorff et al. 1978).