Figure 5. The Dlg1 PDZ2-APC complex mediates ligand-dependent interactions with a Dlg PDZ2 symmetry mate.

Ribbon diagram of the Dlg1 PDZ2-APC complex with one complex colored as in Fig. 1C and a crystal symmetry mate colored with Dlg1 PDZ2 β-strands in cyan, helices αA and αB in teal and purple, and loops in dark blue. The Dlg1 PDZ2 symmetry mate uses its N-terminal loop and βA strand to interact with the APC peptide from the symmetry mate, potentially reflecting a ligand-dependent PDZ clustering mechanism.