6d3p

Crystal structure of an exoribonuclease-resistant RNA from Sweet clover necrotic mosaic virus (SCNMV)

spinqualitylabelsall models 6d3p, resolution 2.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6d3p is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: IRI Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Folded RNA elements that block processive 5' --> 3' cellular exoribonucleases (xrRNAs) to produce biologically active viral noncoding RNAs have been discovered in flaviviruses, potentially revealing a new mode of RNA maturation. However, whether this RNA structure-dependent mechanism exists elsewhere and, if so, whether a singular RNA fold is required, have been unclear. Here we demonstrate the existence of authentic RNA structure-dependent xrRNAs in dianthoviruses, plant-infecting viruses unrelated to animal-infecting flaviviruses. These xrRNAs have no sequence similarity to known xrRNAs; thus, we used a combination of biochemistry and virology to characterize their sequence requirements and mechanism of stopping exoribonucleases. By solving the structure of a dianthovirus xrRNA by X-ray crystallography, we reveal a complex fold that is very different from that of the flavivirus xrRNAs. However, both versions of xrRNAs contain a unique topological feature, a pseudoknot that creates a protective ring around the 5' end of the RNA structure; this may be a defining structural feature of xrRNAs. Single-molecule FRET experiments reveal that the dianthovirus xrRNAs undergo conformational changes and can use "codegradational remodeling," exploiting the exoribonucleases' degradation-linked helicase activity to help form their resistant structure; such a mechanism has not previously been reported. Convergent evolution has created RNA structure-dependent exoribonuclease resistance in different contexts, which establishes it as a general RNA maturation mechanism and defines xrRNAs as an authentic functional class of RNAs. A folded viral noncoding RNA blocks host cell exoribonucleases through a conformationally dynamic RNA structure.,Steckelberg AL, Akiyama BM, Costantino DA, Sit TL, Nix JC, Kieft JS Proc Natl Acad Sci U S A. 2018 Jun 4. pii: 1802429115. doi:, 10.1073/pnas.1802429115. PMID:29866852 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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