4CKB

Vaccinia virus capping enzyme complexed with GTP and SAH

Summary for 4CKB

• Entry DOI: 10.2210/pdb4ckb/pdb
• Related: 4CKC 4CKE
• Descriptor: MRNA-CAPPING ENZYME CATALYTIC SUBUNIT, MRNA-CAPPING ENZYME REGULATORY SUBUNIT, S-ADENOSYL-L-HOMOCYSTEINE, ... (5 entities in total)
• Functional Keywords: transferase-hydrolase complex, trifunctional vaccinia virus mrna capping enzyme, transferase/hydrolase
• Biological source: VACCINIA VIRUS; More
• Cellular location: Virion (Probable): P04298 P04318
• Total number of polymer chains: 4
• Total formula weight: 261798.67

Authors

Kyrieleis, O.J.P.,Chang, J.,de la Pena, M.,Shuman, S.,Cusack, S. (deposition date: 2014-01-02, release date: 2014-03-19, Last modification date: 2023-12-20)

Primary citation

Kyrieleis, O.J.P.,Chang, J.,De La Pena, M.,Shuman, S.,Cusack, S.
Crystal Structure of Vaccinia Virus Mrna Capping Enzyme Provides Insights Into the Mechanism and Evolution of the Capping Apparatus.
Structure, 22:452-, 2014

PubMed Abstract: Vaccinia virus capping enzyme is a heterodimer of D1 (844 aa) and D12 (287 aa) polypeptides that executes all three steps in m(7)GpppRNA synthesis. The D1 subunit comprises an N-terminal RNA triphosphatase (TPase)-guanylyltransferase (GTase) module and a C-terminal guanine-N7-methyltransferase (MTase) module. The D12 subunit binds and allosterically stimulates the MTase module. Crystal structures of the complete D1⋅D12 heterodimer disclose the TPase and GTase as members of the triphosphate tunnel metalloenzyme and covalent nucleotidyltransferase superfamilies, respectively, albeit with distinctive active site features. An extensive TPase-GTase interface clamps the GTase nucleotidyltransferase and OB-fold domains in a closed conformation around GTP. Mutagenesis confirms the importance of the TPase-GTase interface for GTase activity. The D1⋅D12 structure complements and rationalizes four decades of biochemical studies of this enzyme, which was the first capping enzyme to be purified and characterized, and provides new insights into the origins of the capping systems of other large DNA viruses.

PubMed: 24607143
DOI: 10.1016/J.STR.2013.12.014

Experimental method

X-RAY DIFFRACTION (2.8 Å)