Structural proteins and glycoproteins of infectious bronchitis virus particles labeled during growth in chick embryo cells.

Seven Australian infectious bronchitis viruses incorporated radioactive amino acid label during growth in two types of cell culture. From purified virions, four major polypeptides of molecular weights 91,000 (GP91), 51,000 (VP51), 25,000 (GP25) and 23,000 (VP23) were separated by PAGE. Two minor polypeptides of molecular weights 210,000 (GP210) and 185,000 (GP185) were also identified. 3H-glucosamine was incorporated during growth of virus into GP210, GP185, GP91 and GP25. Bromelain digestion of virions removed GP210, GP185 and GP91, leaving VP51, GP25 and VP23 in a large subviral particle. All seven viruses, which were of six serological subtypes, formed apparently identical polypeptide profiles.