An SCP (for example, e1 SCP, was docked and segmented out from the 3.0-Å C6 hexon sub-particle reconstruction) is superposed with the atomic model (ribbon). Density maps (gray) of the Tri1, Tri2A, and Tri2B (segmented out from triplex Tb of the C3 3-fold sub-particle reconstruction) at 3.4 Å are superposed with their atomic models (ribbon). Boxed regions are enlarged in boxes with edges colored correspondingly, with density shown as gray mesh and atomic models as ribbon/sticks.