Figure 8.

Crystal structures of the CusBA-Cu(I) efflux complex. (a) Form Ia of the crystal structure has been designated as the “pre-extrusion 1” state (cyan), with bound copper (purple). (b) Form Ib of the crystal structure has been designated as the “pre-extrusion 2” state (orange), with bound copper (red). (c) Form II of the crystal structure has been designated as the “pre-extrusion 2” state (green), with bound copper (red). (d) Form III of the crystal structure has been designated as the “extrusion” state (magenta), with bound copper (blue). Molecules of CusB are not shown. In each state, the opening of the periplasmic cleft is depicted by the dashed line.