Figure 1.

Plug domain of the yeast Sec61 complex. A stereo representation of the structure of the yeast Sec61 complex as modeled on the experimental structure of the M. jannaschii SecYEβ translocon (van den Berg et al., 2004) is shown with the cytosolic side facing up. The model is shown as a backbone in stereo with the plug domain (residues 52–74), which was replaced by a glycine in the Δplug mutant, displayed as a space-filling contour. Sbh1p is shown in red, Sss1p in orange, and Sec61p is colored from N to C terminus in blue to yellow. Segments P200-E212 and D227-N240 of Sec61p are not present in the model.