Fig. 5.

Interactions of C281. In this view, the dimeric unit of LacI shown in Figure 2 ▶ is turned 90° out of the plane of the paper (1lbh; Lewis et al. 1996). The sidechains for C281 and Y282 on monomer A are indicated in gray (backbone interactions for these positions are not apparent on this figure). The rest of monomer A is depicted as a thin ribbon for clarity. Positions 222, 223, 226, 251, and 255 on monomer B are shown as black balls. Complementary interactions between B:281/282 and A:222, 223, 226, 251, and 255 are not shown.