No Pfam abstract.
This domain is found at the C terminus of the mRNA capping enzyme. The mRNA capping enzyme in yeasts is composed of two separate chains: alpha a mRNA guanyltransferase and beta an RNA 5'-triphosphate. X-ray crystallography reveals a large conformational change during guanyl transfer by mRNA capping enzymes [PUBMED:9160746]. Binding of the enzyme to nucleotides is specific to the GMP moiety of GTP. The viral mRNA capping enzyme is a monomer that transfers a GMP cap onto the end of mRNA that terminates with a 5'-diphosphate tail.