Proteolytic processing of poliovirus polypeptides: antibodies to polypeptide P3-7c inhibit cleavage at glutamine-glycine pairs.
Proteolytic processing of poliovirus polypeptides was examined by the addition of antibodies directed against the viral proteins P3-7c and P2-X to a cell-free translation extract prepared from infected HeLa cells. Antisera to P3-7c specifically inhibited in vitro processing at Gln-Gly pairs. Partial amino acid sequence analysis revealed a second Tyr-Gly pair that is utilized in protein processing. Neither Tyr-Gly cleavage is affected by antibody to P3-7c. Anti-P3-7c antibodies react not only with P3-7c but also with P3-6a and P3-2, two viral polypeptides NH2-coterminal with P3-7c. Preimmune and anti-P2-X antibodies had no effect on the processing of poliovirus proteins in vitro. We conclude that the activity responsible for processing poliovirus polypeptides at Gln-Gly pairs resides in the primary structure of P3-7c (or P3-2 and P3-6a) and not in P2-X.
D000595:Amino Acid Sequence; D000906:Antibodies; D005973:Glutamine; D005998:Glycine; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G; D007700:Kinetics; D010455:Peptides / Q000235:genetics*; D017955:Poliovirus / Q000235:genetics*; D014176:Protein Biosynthesis; D014764:Viral Proteins / Q000235:genetics*
D000906:Antibodies; D007074:Immunoglobulin G; D010455:Peptides; D014764:Viral Proteins; D005973:Glutamine; D005998:Glycine