Characterization of the Structural Proteins of Hazara Virus

Abstract

Hazara virus is closely related to the agents of Congo-Crimean Hemorrhagic Fever (C-CHF) and has been classified as a bunyavirus on the basis of morphological considerations (25). Interest in Hazara virus has been generated because of its potential as a vaccine candidate for C-CHF. In the present study Hazara virus was propagated in BHK-21 cell culture, purified on sucrose density gradients, and the protein composition analyzed by polyacrylamide electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE). Four proteins having molecular weights of 83.8, 51.8, 45.3 and 29.5 x 10³ daltons were resolved and their relative abundance determined. Three glycoproteins were identified and found to be associated with the virion envelope. The fourth protein (MW 51.8 x 10³ daltons) was non-glycosylated and associated with the nucleocapsid. Electron micrographs reveal essentially spherical particles 90 - 130 nanometers in diameter which appear to be highly pleomorphic. Comparison of the physical properties of Hazara virus with other bunyaviruses demonstrates certain similarities and differences in size and chemical composition of structural proteins and in isopycnic densities of intact virions and nucleocapsid particles.