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== Function == | == Function == | ||
[[http://www.uniprot.org/uniprot/CAPSD_BPMS2 CAPSD_BPMS2]] Self-assembles to form the T=3 icosahedral virus shell that protects the viral nucleic acid. Acts as a translational repressor by binding with high specificity to a single stem-loop structure in the genomic RNA that contains the initiation codon of the gene for the viral replicase. Involved in virus assembly through the interaction between a capsid protein dimer and the multiple packaging signals present in the RNA genome.<ref>PMID:16531233</ref> <ref>PMID:18662904</ref> <ref>PMID:26608810</ref> <ref>PMID:8254664</ref> <ref>PMID:9245600</ref> <ref>PMID:9469847</ref> [[http://www.uniprot.org/uniprot/MAT_BPMS2 MAT_BPMS2]] The maturation protein is required for the typical attachment of the phage to the side of the bacterial pili (PubMed:23810697). MP binds to sequences located toward each end of the genome, hence circularizing it (PubMed:26608810). The RNA genome-MP complex is released from the capsid upon host receptor binding (PubMed:23810697). MP enters the cell along with the viral RNA (PubMed:4551992).<ref>PMID:23810697</ref> <ref>PMID:26608810</ref> <ref>PMID:4551992</ref> | [[http://www.uniprot.org/uniprot/CAPSD_BPMS2 CAPSD_BPMS2]] Self-assembles to form the T=3 icosahedral virus shell that protects the viral nucleic acid. Acts as a translational repressor by binding with high specificity to a single stem-loop structure in the genomic RNA that contains the initiation codon of the gene for the viral replicase. Involved in virus assembly through the interaction between a capsid protein dimer and the multiple packaging signals present in the RNA genome.<ref>PMID:16531233</ref> <ref>PMID:18662904</ref> <ref>PMID:26608810</ref> <ref>PMID:8254664</ref> <ref>PMID:9245600</ref> <ref>PMID:9469847</ref> [[http://www.uniprot.org/uniprot/MAT_BPMS2 MAT_BPMS2]] The maturation protein is required for the typical attachment of the phage to the side of the bacterial pili (PubMed:23810697). MP binds to sequences located toward each end of the genome, hence circularizing it (PubMed:26608810). The RNA genome-MP complex is released from the capsid upon host receptor binding (PubMed:23810697). MP enters the cell along with the viral RNA (PubMed:4551992).<ref>PMID:23810697</ref> <ref>PMID:26608810</ref> <ref>PMID:4551992</ref> | ||
| + | <div style="background-color:#fffaf0;"> | ||
| + | == Publication Abstract from PubMed == | ||
| + | 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 A 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 beta-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. | ||
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| + | In situ structures of the genome and genome-delivery apparatus in a single-stranded RNA virus.,Dai X, Li Z, Lai M, Shu S, Du Y, Zhou ZH, Sun R Nature. 2017 Jan 5;541(7635):112-116. doi: 10.1038/nature20589. Epub 2016 Dec 19. PMID:27992877<ref>PMID:27992877</ref> | ||
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| + | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
| + | </div> | ||
| + | <div class="pdbe-citations 5tc1" style="background-color:#fffaf0;"></div> | ||
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| + | ==See Also== | ||
| + | *[[Virus coat protein|Virus coat protein]] | ||
== References == | == References == | ||
<references/> | <references/> | ||
Revision as of 08:27, 18 January 2017
In situ structures of the genome and genome-delivery apparatus in ssRNA bacteriophage MS2
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