Figure 1.

Ribbon diagram of the WW domain found in complex with hPin1 (PDB ID code 1PIN [Ranganathan et al. 1997], residues 6 to 39, with numbering adjusted for consistency with this work). (A) The protein contains two Trp residues; Trp6 is part of a hydrophobic cluster, and Trp29 is exposed to solvent. (B) Jäger et al. (2001) have identified two hydrophobic clusters; the first contains Leu2, Trp6, Tyr19, and Pro32, appearing on the left of the sheet in this orientation; the second contains Arg9, Tyr18, and Phe20 on the opposite side of the sheet. Asn21 belongs to a stabilizing H-bonded network.