English: Assembled major coat protein subunits in Ff (fd, f1, M13) filamentous bacteriophage (Inovirus), exploded view. (This image was used on the cover of Journal of Molecular Biology 355(2), 13 January 2006). Virion axis is vertical. The display in the central portion depicts an axial slab, corresponding to about 1.4% of the total length of the virion. Each subunit is represented as a red space-filling coil following the protein backbone at 5 A radius. Three adjacent subunits are shown in atomic detail (yellow lines) within “semi-transparent” coils. A single isolated subunit is displayed at the right. The coordinates of the single subunit (and the symmetry operators required to generate the assembly of subunits) are deposited with the Protein Data Bank as PDB ID: 2C0X. An unpublished electron micrograph of a full-length phage is displayed at the left, showing a phage aligned by flow on an electron microscope grid as described by Marvin and Hoffmann-Berling 1963, Z. Naturforsch. B18, 884-893.