Opalka N., Tihova M., Brugidou Christophe, Kumar A., Beachy R.N, Fauquet Claude, Yeager M. (2000). Structure of native and expanded sobemoviruses by electron cryo-microscopy and image reconstruction. Journal of Molecular Biology, 303, p. 197-211. ISSN 0022-2836.
Titre du document
Structure of native and expanded sobemoviruses by electron cryo-microscopy and image reconstruction
Année de publication
2000
Type de document
Article
Auteurs
Opalka N., Tihova M., Brugidou Christophe, Kumar A., Beachy R.N, Fauquet Claude, Yeager M.
Source
Journal of Molecular Biology, 2000,
303, p. 197-211 ISSN 0022-2836
Rice yellow mottle virus (RYMV) and southern bean mosaic virus, cowpea strain (SCPMV) are members of the Sobemovirus genus of RNA-containing viruses. We used electron cryo-microscopy (cryo-EM) and icosahedral image analysis to examine the native structures of these two viruses at 25 A resolution. Both viruses have a single tightly packed capsid layer with 180 subunits assembled on a T = 3 icosahedral lattice. Distinctive crown-like pentamers emanate from the 12 f-fold axes of symmetry. The exterior face of SCPMV displays deep valleys along the 2-fold axes and protrusions at the quasi-3-fold axes. While having a similar topography, the surface of RYMV is comparatively smooth. Two concentric shells of density reside beneath the capsid layer of RYMV and SCPMV, which we interpret as ordered regions of genomic RNA. In the absence of divalent cations, SCPMV particles swell and fracture, whereas the expanded form of RYMV is stable. We previously proposed that the cell-to-cell movement of RYMV in xylem involves chelation of Ca2+ from pit membranes of infected cells, thereby stabilizing the capsid shells and allowing a pathway for spread of RYMV through destabilized membranes. In the context of this model, we propose that the expanded form of RYMV is an intermediate in the in vivo assembly of virions. (Résumé d'auteur)
