Fig. 2.

Features of proheads. (A) Low-resolution image of proheads (derivative filtered). (B) Top view of the pseudoatomic structure of Φ29. Dashed lines outline two complex pentameric features: (i) lines in blue connect the icosahedral vertices, (ii) the red pentamer is limited by the protruding domains of the monomers. The latter is similar in size to the former feature, but slightly rotated. (C) High-resolution image of a prohead lying on its side, imaging force 130 pN. (D) Same for upright prohead. The dotted line marks the cross-section shown in F. (E) Size distribution of observed pentamer sides including tip convolution (N = 12, SD = 1.6 nm). (F) Profile of the topography at the indicated cross-section, compared to undeformed shape (dashed line).