5af2
Crystal structure of the C-terminal 2',5'-phosphodiesterase domain of group A rotavirus protein VP3
Structural highlights
FunctionVP3_ROTSH Multifunctional enzyme involved in mRNA capping. Catalyzes the formation of the 5' cap structure on the viral plus-strand transcripts. Specifically binds to GTP and displays guanylyltransferase and methyltransferase activities. Has affinity for ssRNA but not for dsRNA. Capping activity is non-specific and caps RNAs that initiate with either a G or an A residue. Together with VP1 polymerase, forms a VP1-VP3 complex positioned near the channels situated at each of the five-fold vertices of the core. Following infection, the outermost layer of the virus is lost, leaving a double-layered particle (DLP) made up of the core and VP6 shell. VP1 then catalyzes the transcription of fully conservative plus-strand genomic RNAs that are capped by VP3 and extruded through the DLP's channels into the cytoplasm where they function as mRNAs for translation of viral proteins. DLPs probably have an RNA triphosphatase activity as well, whereas open cores do not.[HAMAP-Rule:MF_04128][1] Counteracts the host innate immune response thanks to its phosphodiesterase that degrades the 5'-triphosphorylated, 2'-5' linked adenylate oligomers produced by the host cell IFN-inducible 2',5'-oligoadenylate synthetase (OAS). The host RNaseL is therefore not activated.[HAMAP-Rule:MF_04128][2] Publication Abstract from PubMedIn response to viral infections, the mammalian innate immune system induces the production of the second messenger 2'-5' oligoadenylate (2-5A) to activate latent ribonuclease L (RNase L) that restricts viral replication and promotes apoptosis. A subset of rotaviruses and coronaviruses encode 2',5'-phosphodiesterase enzymes that hydrolyze 2-5A, thereby inhibiting RNase L activation. We report the crystal structure of the 2',5'-phosphodiesterase domain of group A rotavirus protein VP3 at 1.39 A resolution. The structure exhibits a 2H phosphoesterase fold and reveals conserved active site residues, providing insights into the mechanism of 2-5A degradation in viral evasion of host innate immunity. This article is protected by copyright. All rights reserved. Crystal structure of the C-terminal 2',5'-phosphodiesterase domain of group A rotavirus protein VP3.,Brandmann T, Jinek M Proteins. 2015 Mar 10. doi: 10.1002/prot.24794. PMID:25758703[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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