[Molecular biology characteristics of an attenuated mutant of the Eastern equine encephalomyelitis virus].

The main molecular biology parameters of an attenuated mutant DMS-20/6 of eastern equine encephalomyelitis virus derived by treatment with dimethylsulphate of the wild type virus (strain No. 627) were determined. The sedimentation coefficient of sucrose density gradient purified and concentrated virus was 280 S, the buoyant density of virions in sucrose density gradient was 1.19 g/cm3. The DMS-20/6 virion had 3 proteins with molecular weights of 56, 50, and 34 kilodaltons, and the size of virions by negative staining was 58-77 nm.