FIGURE 2.
Comparison of LD motif binding to CCM3. A, stereoviews show refined 2Fo −Fc electron density for CCM3 in complex with paxillin LD motifs, LD1, LD2, and LD4. Maps are contoured at 2 σ (light blue) and 0.6 σ (blue). B, shown is a close-up view of the LD motif peptides. All peptides are shown in an identical orientation with respect to the CCM3 FAT homology domain, and the N and C termini are labeled. LD1 is colored gray, LD2 is green, and LD4 is salmon. Residues are labeled, and side chains are shown. C, superposition of the CCM3 FAT homology domains bound to paxillin LD motifs is shown. The LD motifs bind CCM3 at the same location in the HP1 binding site. CCM3-LD1 is colored gray, CCM3-LD2 is colored dark green, and CCM3-LD4 is colored light green (CCM3) and salmon (LD4). α-Helical regions of CCM3 are shown as cylinders. D, sequence alignment of the paxillin LD motifs is shown. Residues built in the complex structures are shaded, and the consensus eight-residue LD motif is shown below. ELD or DLE tri-peptide unit is colored red.