InterPro domain: IPR001339

This entry represents the adenylation domain of the mRNA capping enzyme [ 1 ]. The mRNA-capping enzyme is composed of two separate chains alpha and beta, respectively a mRNA guanylyltransferase and an RNA 5'-triphosphatase [ 2 ]. 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.

It contains a catalytic core composed of an adenylation domain and a C-terminal OB-fold domain containing conserved sequence motifs. The adenylation domain binds ATP and contains many active site residues [ 2 , 3 ].

1. X-ray crystallography reveals a large conformational change during guanyl transfer by mRNA capping enzymes. Cell 89, 545-53
2. Structure, mechanism, and evolution of the mRNA capping apparatus. Prog. Nucleic Acid Res. Mol. Biol. 66, 1-40
3. Structure of an mRNA capping enzyme bound to the phosphorylated carboxy-terminal domain of RNA polymerase II. Mol. Cell 11, 1549-61