FIGURE 1.

Structure and conformational changes of oxidized and reduced BigR. A, structural comparison of the oxidized (blue) and reduced (red) monomers. The intrachain disulfide bond is represented as sticks, and the corresponding cysteine residues are labeled. Secondary structure elements are indicated. B, 2F_o − F_c electron density map contoured at 1.2σ showing the disulfide between Cys-42 and Cys-108 in the oxidized monomer A. C, superposition of the BigR dimers. Light and dark colors are used to distinguish the homodimer subunits. The figure was produced by superposing the C-α atoms of residues 21–32 (helix 1) from both monomers. The distances between the Gln-67 C-α atoms of helix 4 from opposite subunits are indicated.