RESPIRATORY SYNCYTIAL VIRUS POLYPEPTIDES - THEIR LOCATION IN THE VIRION

Purified respiratory syncytial (RS) virus contains, in addition to the six to seven polypeptides previously reported (S. Levine, 1977, J. Virol., 21, 427-431), a large polypeptide (VPO), MW > 160,000. Treatment of purified virus with trypsin removes the major glycoproteins, VP1 and 2. Treatment of purified virus with 2% Triton X-100 in HBSS (equivalent to 0.15 M NaCl) solubilizes the glycoproteins VP1 and 2 and a nonglycosylated protein, VP5, MW 28,000, which suggests that VP5 is an M protein. Treatment with 2% Triton X-100 in 0.4 M NaCl solubilizes all the virion proteins except VPO and VP3, which are also not solubilized in 0.8 M NaCl. The results suggest that VP3, MW 44,000, is the major nucleocapsid protein, and that VPO is not a superficial contaminant of the virus preparation, but instead is closely associated with the nucleocapsid. Only VP3 is present in nucleocapsids isolated from RS virus-infected cells by isopycnic centrifugation in CsCl. © 1979.