Structure of glycosylated and unglycosylated gag polyproteins of Rauscher murine leukemia virus: carbohydrate attachment sites.
The structural relationships among the gag polyproteins Pr65gag, Pr75gag, and gPr80gag of Rauscher murine leukemia virus were studied by endoglycosidase H digestion and formic acid cleavage. Fragments were identified by precipitation with specific antisera to constituent virion structural proteins followed by one-dimensional mapping. Endoglycosidase H reduced the size of gPr80gag to that of Pr75gag. By comparing fragments of gPr80gag and the apoprotein Pr75gag, the former was shown to contain two mannose-rich oligosaccharide units. By comparing fragments of Pr65gag and Pr75gag, the latter was shown to differ from Pr65gag at the amino terminus by the presence of a leader peptide approximately 7,000 daltons in size. The internal and carboxyl-terminal peptides of the two unglycosylated polyproteins were not detectably different. The location of the two N-linked carbohydrate chains in gPr80gag has been specified. One occurs in the carboxyl-terminal half of the polyprotein at asparagine177 of the p30 sequence and the other is found in a 23,000-dalton fragment located in the amino-terminal region of gPr80gag and containing the additional amino acid sequences not found in Pr65gag plus a substantial portion of p15.
D000595:Amino Acid Sequence; D002241:Carbohydrates / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D006023:Glycoproteins / Q000032:analysis*; D046911:Macromolecular Substances; D008970:Molecular Weight; D010455:Peptides / Q000032:analysis; D011925:Rauscher Virus / Q000032:analysis*; D014357:Trypsin; D014764:Viral Proteins / Q000032:analysis*
D002241:Carbohydrates; D006023:Glycoproteins; D046911:Macromolecular Substances; D010455:Peptides; D014764:Viral Proteins; D014357:Trypsin