The viral envelope, obtained by budding through membranes of the ER and/or Golgi apparatus, invariably contains two virus-specified (glyco)protein species, S and M. Glycoprotein S comprises the large surface projections, while the M protein is a triple-spanning transmembrane protein.
White Bream virus is a species in the genus Bafinivirus in the subfamily Torovirinae in the family Coronaviridae in the Order Nidovirales.