Possible domain swapping in H. volcanii MSH. The subunit of the trimer closest to the viewer is rendered in the same form and colors as in figure 1, with the C-terminal domain on the right. The C-terminal domain on the left, also rendered as a red cartoon ribbon trace would instead be connected to the green β8/α8 barrel if domain swapping occurs. In the domain swap the C-terminal domain connected to the barrel of one subunit (green) would be donated to complete the active site of the neighboring barrel shown as a blue surface rather than its own. The short disordered surface loops (372-380) are depicted as red dotted lines.