Figure 3.
Crystal structure of sHAI-1 and interdomain interaction. A, overall compact arrangement of sHAI-1. The N (salmon), I (blue), K1 (yellow), 365-linker (forest green), and K2 domains (purple) were observed and packed closely together. Glycans at Asn66 (green) and the P1 site (Arg260, yellow) are shown as sticks and spheres. The missing LDLRA domain and linkers are drawn with a gray dashed line. B, MANEC domain embedded into the concave (right) formed by the rest part of sHAI-1 (left, surface in gray). C, electrostatic potential analysis of sHAI-1 revealed opposite charge existing in the contact area between MANEC domain and IK1-K2. B and C are rotated clockwise along y axis for 60° compared with A. D, the hydrogen bonding network in E was supported by the well-defined electron density map (2Fo − Fc, gray) at contoured level of 1.0 σ. E and F, hydrophilic interaction between MANEC domain and the rest of sHAI-1. G, hydrophobic interactions between 365-linker and MANEC, and Kunitz domain 1. H, negative charged 365-linker was attracted by the positively charged P1 site loop.