Structural highlights
FunctionP1_BPPH6 P1 is the major inner capsid (core) protein of the polyhedral procapsid, which is responsible for genomic replication and transcription. Forms a dodecahedral shell from 60 asymmetric dimers. Binds to RNA and may be involved in genomic packaging. Publication Abstract from PubMedThe cystovirus varphi6 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. varphi6 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. Subunit Folds and Maturation Pathway of a dsRNA Virus Capsid.,Nemecek D, Boura E, Wu W, Cheng N, Plevka P, Qiao J, Mindich L, Heymann JB, Hurley JH, Steven AC Structure. 2013 Aug 6;21(8):1374-83. doi: 10.1016/j.str.2013.06.007. Epub 2013, Jul 25. PMID:23891288[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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