Figure 3.

SH3 binding minimotif family. SH3 binding minimotifs were grouped into the 10 minimotif categories using the relational database and Shannon Information Content similarity metric. Surface plots of structures identified for 8 of the 10 group (1ZSG, black; 1NM7, pink; 1AZE, cyan; 2BZ8, blue; 1CKA, magenta; 1OPL, red; 1RLQ orange; 1H3H, green; 1NYG, brown) are shown. The carbon backbones of SH3 domains were fit using Molmol with residues in the β1 and β4 sheets, and the 3-10 helix, to an RMSD of 0.9 [33]. An overlay of each SH3 domain carbon backbone with its peptide minimotif is color matched and relevant minimotif side chain bonds are represented as thickened lines; the surface plot for the overlay is derived from the 1ZSG structure). Structures of the ligands for the RKxxYxxY and WxxxFxxLE minimotifs are not known, but the binding sites on the SH3 domains derived from NMR chemical shift mapping experiments are indicated. RxxPxxP and PxxxPR minimotifs show structures with the peptides in opposing orientations. The consensus sequences (C), total number of minimotifs for C (M), and percentage of potentially ambiguous ligand instances (A) in the MnM 2 database are indicated.