Protein is linked to the 5' end of poliovirus RNA by a phosphodiester linkage to tyrosine

Concepts

Poliovirus RnaVirus StructureViral ReplicationMolecular VirologyBiochemistryTyrosine ResidueNatural SciencesPathogenesisMolecular BiologyVirologyPoliovirus Rna-linked ProteinFree TyrosineViral Structural ProteinPolioMedicineVirus GenePhosphodiester LinkageViral Genetics

TL;DR

VPg is covalently attached to the 5′ end of poliovirus RNA via a phosphodiester bond between a tyrosine residue and the 5′‑terminal uridine. VPg was purified and partially characterized, and acid hydrolysis of [3H]tyrosine‑labeled VPg‑pU followed by venom phosphodiesterase release of free tyrosine demonstrated the phosphodiester linkage. VPg was released from RNA by ribonuclease digestion and phenol extraction, has an approximate molecular weight of 12,000, yields tyrosine‑phosphate upon acid hydrolysis, and contains a single tyrosine residue per molecule.

Abstract

Purification and partial characterization of the poliovirus RNA-linked protein (VPg) are described. VPg has been freed from the RNA by ribonuclease digestion and phenol extraction. Gel filtration chromatography of VPg-pUp (labeled with 32P) in 0.5% sodium dodecyl sulfate or 6 M guanidine HCl indicates that it has a molecular weight of about 12,000. VPg is bound to the 5' end of poliovirion RNA by a phosphodiester bond between a tyrosine residue in the VPg molecule and the 5'-terminal uridine. After acid hydrolysis of [3H]tyrosine-labeled VPg-pU, free tyrosine can be released by venom phosphodiesterase. Acid hydrolysis of VPg-p labeled with either 32P or [3H] tyrosine yields tyrosine-phosphate. There appears to be only 1 tyrosine residue per VPg molecule.