Fig. 1 Overall structure and organization of the major and minor capsid proteins in HAdV-D26. Overall structure and organization of the major and minor capsid proteins in HAdV-D26. (A) Representative micrograph of frozen-hydrated HAdV-D26 virions (defocus, 1.16 μm) (B) Slice through the center of HAdV-D26 particle showing the cross section of densities of the MCPs and closely associated minor proteins. The shaft repeats and knob domain of the fiber can be seen, and the packaged double-stranded DNA in the middle is disordered. (C) Radially color-coded surface representation of the cryo-EM reconstruction of HAdV-D26, a view down the icosahedral threefold axis. One icosahedral facet is identified by a black triangle. (D) Schematic representation of AdV capsid showing the location and organization of various proteins in the AdV capsid. A list of symbols and the proteins they represent is shown on the right. The copy numbers of the capsid proteins are indicated in parentheses, and “?” indicates the uncertainty in the copy numbers. (E) Exterior view of a triangular facet. The locations of the structurally distinct hexon-1 to hexon-4 are identified by differently colored hexagons, surface representations of the hexons (hexon-1 to hexon-4) are shown in four different colors (light blue, pink, green, and khaki, respectively), and the PB is shown in magenta. The green triangle represents an icosahedral facet and is equivalent to the black triangle in (C). The hexons shown in gray belong to neighboring facets. The locations of the NT triskelions and CT coiled coils (four-helical bundle; 4-HLXB) of protein IX are labeled. (F) Interior view of the facet showing the location of the minor proteins relative to each other and to the MCPs. Surface representations of the proteins IIIa, VIII-U, VIII-V, and pVIn are shown in dark green, orange, yellow, and red, respectively. With the exception of pVIn (red), multiple copies of the same-colored proteins are related to each other by the icosahedral symmetry. Xiaodi Yu et al. Sci Adv 2017;3:e1602670 Copyright © 2017, The Authors