Figure 2.

Ribbon and surface representations of the x-ray crystal structure of the CD11a I domain (4) showing residues affected by the addition of soluble ICAM-1 domains 1 and 2. Colors indicate the extent of line broadening: red, large decrease in peak height; blue, medium or no decrease in peak height; gray, unassigned in the complex due to spectral overlap. The magnesium ion of the MIDAS is shown in yellow. For the ribbon diagrams, the color coding of the ribbon indicates changes in peak intensity of amide proton signals, and colors of side chains indicate changes in peak intensity of methyl proton signals. For the surface representations, red indicates a large decrease in peak height of ¹⁵N-amide or ¹³C-methyl signals. (A and B) View of α-helix 7 and the opposing β-sheet. (C and D) Opposite face of the I domain showing α-helix 4.