8qkp

Asymmetric structure of Satellite Tobacco Necrosis Virus-Like Particle with PS2/3 gRNA

spinqualitylabelsall models 8qkp, resolution 5.26Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8qkp is a 60 chain structure with sequence from Satellite tobacco necrosis virus 1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 5.26Å Ligands: CA, SRA, SSU Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CAPSD_STNV1 Self-assembles to form an icosahedral capsid of 17 nm in diameter. Publication Abstract from PubMed Here we confirm, using genome-scale RNA fragments in assembly competition assays, that multiple sub-sites (Packaging Signals, PSs) across the 5' two-thirds of the gRNA of Satellite Tobacco Necrosis Virus-1 make sequence-specific contacts to the viral CPs helping to nucleate formation of its T = 1 virus-like particle (VLP). These contacts explain why natural virions only package their positive-sense genomes. Asymmetric cryo-EM reconstructions of these VLPs suggest that interactions occur between amino acid residues in the N-terminal ends of the CP subunits and the gRNA PS loop sequences. The base-paired stems of PSs also act non-sequence-specifically by electrostatically promoting the assembly of CP trimers. Importantly, alterations in PS-CP affinity result in an asymmetric distribution of bound PSs inside VLPs, with fuller occupation of the higher affinity 5' PS RNAs around one vertex, decreasing to an RNA-free opposite vertex within the VLP shell. This distribution suggests that gRNA folding regulates cytoplasmic genome extrusion so that the weakly bound 3' end of the gRNA, containing the RNA polymerase binding site, extrudes first. This probably occurs after cation-loss induced swelling of the CP-shell, weakening contacts between CP subunits. These data reveal for the first time in any virus how differential PS folding propensity and CP affinities support the multiple roles genomes play in virion assembly and infection. The high degree of conservation between the CP fold of STNV-1 and those of the CPs of many other viruses suggests that these aspects of genome function will be widely shared. Visualizing Viral RNA Packaging Signals in Action.,Wroblewski E, Patel N, Javed A, Mata CP, Chandler-Bostock R, Lekshmi BG, Ulamec SM, Clark S, Phillips SEV, Ranson NA, Twarock R, Stockley PG J Mol Biol. 2024 Nov 15;436(22):168765. doi: 10.1016/j.jmb.2024.168765. Epub 2024 , Aug 29. PMID:39214281 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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