4bx4

Publication Abstract from PubMed

The hallmark of a virus is its capsid, which harbors the viral genome and is formed from protein subunits, which assemble following precise geometric rules. dsRNA viruses use an unusual protein multiplicity (120 copies) to form their closed capsids. We have determined the atomic structure of the capsid protein (P1) from the dsRNA cystovirus Phi8. In the crystal P1 forms pentamers, very similar in shape to facets of empty procapsids, suggesting an unexpected assembly pathway that proceeds via a pentameric intermediate. Unlike the elongated proteins used by dsRNA mammalian reoviruses, P1 has a compact trapezoid-like shape and a distinct arrangement in the shell, with two near-identical conformers in nonequivalent structural environments. Nevertheless, structural similarity with the analogous protein from the mammalian viruses suggests a common ancestor. The unusual shape of the molecule may facilitate dramatic capsid expansion during phage maturation, allowing P1 to switch interaction interfaces to provide capsid plasticity.

Plate Tectonics of Virus Shell Assembly and Reorganization in Phage Phi8, a Distant Relative of Mammalian Reoviruses.,El Omari K, Sutton G, Ravantti JJ, Zhang H, Walter TS, Grimes JM, Bamford DH, Stuart DI, Mancini EJ Structure. 2013 Jul 23. pii: S0969-2126(13)00240-2. doi:, 10.1016/j.str.2013.06.017. PMID:23891291^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.