Figure 5.
Figure 5. Modes of PDZ C-terminal and internal recognition.
In PDZ C-terminal ligand recognition, the carboxylate-binding
loop enforces C-terminal binding by preventing extension past
the P(0) residue. In the -finger
internal PDZ recognition mode of recognition, used by
nNOS-syntrophin7 and presumably disulfide-containing ligands8, a
sharp turn in the ligand allows it to bypass the steric
requirement imposed by the carboxylate-binding loop. The Pals1
-Par-6 PDZ interaction represents a new type of internal
interaction in which the carboxylate-binding loop is deformed to
allow for extension past the P(0) residue. An interaction with
the P(+1) residue is critical for this mode of recognition.
-finger
internal PDZ recognition mode of recognition, used by
nNOS-syntrophin7 and presumably disulfide-containing ligands8, a
sharp turn in the ligand allows it to bypass the steric
requirement imposed by the carboxylate-binding loop. The Pals1
-Par-6 PDZ interaction represents a new type of internal
interaction in which the carboxylate-binding loop is deformed to
allow for extension past the P(0) residue. An interaction with
the P(+1) residue is critical for this mode of recognition.