Nido -type capping
RNAs are capped by a unique viral reaction. These viruses encode an RNA:GDP polyribonucleotidyltransferase (PRNTase) that forms a covalent bond to the 5' end of the viral RNA through a monophosphate group. The enzyme then transfers the 5'-monophosphate RNA to GDP and forms the GpppRNA structure, These activities are encoded in the viral RdRp complex. The RNA is further N7 methylated and 2'O methylated by two other viral enzymes .
TPase (involves covalent link enz-His-RNA)
N7methyltransferase Rhea 65380
2'O methylase : Rhea 67020