5TC1
In situ structures of the genome and genome-delivery apparatus in ssRNA bacteriophage MS2
Summary for 5TC1
| Entry DOI | 10.2210/pdb5tc1/pdb |
| Related | 2MS2 |
| EMDB information | 8397 |
| Descriptor | Capsid protein, Maturation protein, phage MS2 genome (3 entities in total) |
| Functional Keywords | asymmetric cryoem reconstruction, ssrna genome structure, genome-delivery apparatus, genome-capsid interactions, viral protein-rna complex, viral protein/rna |
| Biological source | Enterobacteria phage MS2 More |
| Total number of polymer chains | 10 |
| Total formula weight | 1302188.96 |
| Authors | |
| Primary citation | Dai, X.,Li, Z.,Lai, M.,Shu, S.,Du, Y.,Zhou, Z.H.,Sun, R. In situ structures of the genome and genome-delivery apparatus in a single-stranded RNA virus. Nature, 541:112-116, 2017 Cited by PubMed Abstract: Packaging of the genome into a protein capsid and its subsequent delivery into a host cell are two fundamental processes in the life cycle of a virus. Unlike double-stranded DNA viruses, which pump their genome into a preformed capsid, single-stranded RNA (ssRNA) viruses, such as bacteriophage MS2, co-assemble their capsid with the genome; however, the structural basis of this co-assembly is poorly understood. MS2 infects Escherichia coli via the host 'sex pilus' (F-pilus); it was the first fully sequenced organism and is a model system for studies of translational gene regulation, RNA-protein interactions, and RNA virus assembly. Its positive-sense ssRNA genome of 3,569 bases is enclosed in a capsid with one maturation protein monomer and 89 coat protein dimers arranged in a T = 3 icosahedral lattice. The maturation protein is responsible for attaching the virus to an F-pilus and delivering the viral genome into the host during infection, but how the genome is organized and delivered is not known. Here we describe the MS2 structure at 3.6 Å resolution, determined by electron-counting cryo-electron microscopy (cryoEM) and asymmetric reconstruction. We traced approximately 80% of the backbone of the viral genome, built atomic models for 16 RNA stem-loops, and identified three conserved motifs of RNA-coat protein interactions among 15 of these stem-loops with diverse sequences. The stem-loop at the 3' end of the genome interacts extensively with the maturation protein, which, with just a six-helix bundle and a six-stranded β-sheet, forms a genome-delivery apparatus and joins 89 coat protein dimers to form a capsid. This atomic description of genome-capsid interactions in a spherical ssRNA virus provides insight into genome delivery via the host sex pilus and mechanisms underlying ssRNA-capsid co-assembly, and inspires speculation about the links between nucleoprotein complexes and the origins of viruses. PubMed: 27992877DOI: 10.1038/nature20589 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.6 Å) |
Structure validation
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