Figure 4.
The structure of WIF-1ΔC. (a) Ribbon diagram of WIF-1ΔC. The orientation of the WIF domain is the same as in Fig. 1b. The WIF domain and EGFs I–III are colored light blue, magenta, yellow and red, respectively. Ten disulfide bridges are shown as gray sticks and marked with Roman numerals. DPPC is shown as spheres. (b) Electrostatic properties of WIF-1ΔC. The protein is shown as solvent-accessible surface colored by electrostatic potential contoured at ± 8 kT/e (red, acidic; blue, basic). GlcNAc moieties on Asn88 (WIF domain) and Asn245 (EGF III) are shown as yellow spheres. A potential Wnt3a-binding surface is circled. (c) Orthogonal relative orientation of the DPPC head group between superimposed structures of WIF-1ΔC (light blue; DPPC colored as in Fig. 1c, d) and WIF-1WD–EGF-I (green). (d) Hydrophobic contact formed between the WIF domain hydrophobic patch (marked with an asterisk in Fig. 3b, 180° view) and EGF III. Interacting residues are shown as sticks.