Figure 3 - full size

Figure 3.
The x-ray crystal structure of ePDZ-a in complex with the ARVCF peptide. (A) Ribbon representations of the overall structure. The cpPDZ and FN3 portions and the peptide are shown in gray, cyan, and yellow, respectively. Missing residues for the linker segment are indicated with dashed lines. (B) Clamping of the peptide by ePDZ-a. Only the region in the dashed box in A is shown. The surfaces originating from the cpPDZ and FN3 portions are shown in gray and cyan, respectively, and the peptide is shown as a yellow stick model. (C) Interactions of the FN3 loops with the cpPDZ/peptide complex. The three FN3 loops (BC, DE, and FG loops) are shown as sticks in blue, cyan, and red, respectively. The surface of the PDZ portion is shown in gray, and the peptide is shown as yellow spheres. In Lower, the surfaces of the PDZ and peptide portions in contact with the BC, DE, and FG loops (within 5 Å are shown in blue, cyan, and red, respectively, and those in contact with both BC and FG loops are in magenta. The peptide surfaces without FN3 contact are shown in yellow, and the green line encloses the bound peptide. (D) Superposition of wild-type PDZ (PDB entry 1MFG, green) and cpPDZ (gray). The original and new termini are indicated. The rmsd for the equivalent 97 Cα atoms was 0.54 Å. The structures are in the same orientation as in A.