Fig. 3.

The Y-complex assembles into two reticulated concentric rings within the nuclear and cytoplasmic rings of the NPC. (a) Negative staining structure of the human Y-complex at 33 Å resolution (top) that was localized by a systematic fitting approach within the tomographic map of the human NPC (32 Å resolution; middle) and the X.l. NPC structure (20 Å resolution; bottom). Images reproduced from Refs. [7], [50]. (b) Crystal structure of the Y-complex vertex [51], [53] (top) that was localized within the tomographic map of the human NPC resolved to 32 Å [7] (bottom). (c) Fits of X-ray structures of sufficient size into the tomographic map of the human NPC resolved to 23 Å [51]. The fit of the X-ray structure of the yeast vertex (top [53]) is shown in comparison to an independently obtained hybrid model of the entire Y-complex (bottom [51]).