Fig. 4. Schematic drawings of (A) the recombinant human IFN-g D' dimer and (B) IFN-g. On the left-hand side, the alpha helices are represented as cylinders, and the nonhelical regions are shown as tubes. The NH2- and COOH-terminal ends of the helices are colored blue and red, respectively. On the right-hand side, the helices are represented as circles, and the nonhelical regions are shown as solid or dashed lines, depending on whether they are above or below the plane of the figure. The NH2-terminal ends of the helices are darkened. The regions labeled B* represent a kinked region of IFN-g that is not helical but shows some helical features.