Figure 5.

(a) Contoured cross sections of mass density from the three-dimensional structures of native DLP (blue) and 7D9 DLP:IgA complex (red), viewed perpendicular to the icosahedral fivefold axis. Each contour represents a mass density difference of about 0.37 ς. The cross sections, labeled I–V, were extracted from radii between 261 Å and 325 Å (b). The upper panel of cross sections depicts the distribution of mass surrounding the mRNA release channel, with the icosahedral fivefold axis passing through the center. The lower panel of cross sections provides a close-up view of the mass distribution in one of the five trimers (indicated in the corresponding upper panel by a dashed box). The arrowheads in cross section III, lower panel, denote representative intermolecular interactions that are different in the two structures. Measurements of three specific mass translocations are also given. Scale bars, 50 Å. (b) Graphical representation of the radii from which cross sections were extracted in a. The cross sections are shown as semitransparent gray planes. The five VP6 trimers surrounding the mRNA release channel in the native DLP are colored in blue, and the underlying VP2 capsid layer is shown in green. (c) A portion of the surface representation of the native DLP, viewed along the icosahedral fivefold axis. The position of the fivefold axis along which the sections shown in a were taken is marked. The pair of VP6 trimers surrounding the twofold axis is also indicated.