FIGURE 3.

Tilt series of putative intermediates of double-membraned vesicles induced by poliovirus 3AB. A, schematic side view of an invaginating vesicle (left panel). An electron beam coming from above the virtual vesicle would generate the two-dimensional projection shown in the 0^o image in the right panel. Rotation of the model invaginated structure by 30^o and 45^o around a horizontal tilt axis is shown. B, schematic side view of a liposome that is engulfing a second liposome (left panel). The modeled vesicle was rotated 0^o, 30^o, and 45^o around a horizontal axis, and the corresponding two-dimensional projections are shown in the right panel. C–F, four proteoliposomes that contained 3AB were rotated 0^o and 45^o around a tilt axis perpendicular to the electron beam and imaged by cryo-electron microscopy. Scale bar = 100 nm.