VPG-type capping
Enzymatic reaction:
RNA-dependent RNA polymerase (RdRp) attaches one or more nucleotides to a Tyrosine in the target protein through a nucleotidyl-transferase reaction
(Nucleotidylylation).
Picornavirus VPG can be removed by cellular TDP2/VPg unlinkase . This would enhance viral replication, but it is not clear why it does not elicit a RIG -like receptors (RLR) antiviral response.