FIG. 26.

Schematic diagram (left) and cryoreconstruction (right) of the ssRNA insect virus FHV (family Nodaviridae). The capsid of FHV consists of 180 copies of a single subunit arranged with T=3 icosahedral symmetry. Each icosahedral asymmetric unit consists of three quasi-equivalent subunits, labeled A, B, and C. A and B are related by a quasi-twofold axis (open ellipse). The positions of a peptide arm and a portion of the RNA genome that adopts a highly ordered, double-stranded loop are also indicated in the diagram. The isosurface rendering of the image reconstruction shows prominent peaks on the viral surface at local threefold positions (open triangle in diagram). Positions of four icosahedral symmetry axes (2, 5, and 3) are marked on the reconstruction. Adapted from reference 66 with the permission of the author and the publisher.