Structural polypeptides of the american (VR-2332) strain of porcine reproductive and respiratory syndrome virus

The structural polypeptides of the isolate VR-2332 of porcine reproductive and respiratory syndrome virus were analyzed in sucrose gradient-purified virions. The virus had all average density of 1.15 g/cm³ and contained, by SDS-PAGE, three major polypeptides with apparent molecular weights of 15, 19 and 26-30 kDa, which were designated as nucleocapsid (N), matrix (M) and envelope (E), respectively. The predominant structural protein was N. N-glycosidase F digestion only affected E whereas O- glycosidase or endoglycosidase H digestion had no effect, suggesting that the viral glycoproteins contain only complex N-linked carbohydrates.