Subunit Folds and Maturation Pathway of a dsRNA Virus Capsid
| Authors | |
|---|---|
| Year of publication | 2013 |
| Type | Article in Periodical |
| Magazine / Source | Structure |
| MU Faculty or unit | |
| Citation | |
| Web | http://www.ncbi.nlm.nih.gov/pubmed/23891288 |
| Doi | http://dx.doi.org/10.1016/j.str.2013.06.007 |
| Field | Microbiology, virology |
| Keywords | Bacteriophage phi6; Cystoviridae; cryo-electron microscopy; capsid structure; capsid expansion; segmented genome; conformational change; RNA packaging |
| Description | The cystovirus phi 6 shares several distinct features with other double-stranded RNA (dsRNA) viruses, including the human pathogen, rotavirus: segmented genomes, nonequivalent packing of 120 subunits in its icosahedral capsid, and capsids as compartments for transcription and replication. phi 6 assembles as a dodecahedral procapsid that undergoes major conformational changes as it matures into the spherical capsid. We determined the crystal structure of the capsid protein, P1, revealing a flattened trapezoid subunit with an alpha-helical fold. We also solved the procapsid with cryo-electron microscopy to comparable resolution. Fitting the crystal structure into the procapsid disclosed substantial conformational differences between the two P1 conformers. Maturation via two intermediate states involves remodeling on a similar scale, besides huge rigid-body rotations. The capsid structure and its stepwise maturation that is coupled to sequential packaging of three RNA segments sets the cystoviruses apart from other dsRNA viruses as a dynamic molecular machine. |
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