Several features of Bacteriorhodopsin are shown:
1. Overall structure, lipid binding, and roles of amino acids.
PDB file 1brr
2. Continued
3. Conformational changes in the M state
onPDB file 1cwq
The photocycle for bacteriorhodopsin starts at the top, where a photon of light is absorbed. On a rapid timescale, the protein transitions from the ground state to states K, L and M, and loses a proton to the outside of the membrane. Now on a millisecond time scale, the protein continues to states N and O, and it picks up a proton from the inside of the membrane. |
Figure is from the following paper:
Protein conformational changes in the bacteriorhodopsin photocycle: comparison of findings from electron and X-ray crystallographic analyses. Recommended for a full discussion on the detection of various conformational states. |
4. Continued: Changes in water channels in the M state