How does bacteriorhodopsin couple photoexcitation with proton pumping?
A) Bacteriorhodopsin has a proton channel domain.
B) Bacteriorhodopsin makes the membrane porous to protons.
C) Light-induced conformational changes of retinal cause the protein to extrude one proton.
D) All of the above.
E) None of the above.

Question

Quizplus · Accepted Answer

Bacteriorhodopsin is a light-driven proton pump that uses retinal as a chromophore. Upon photoexcitation, retinal undergoes a conformational change that triggers a cascade of structural rearrangements within the protein, resulting in the extrusion of one proton from the cytoplasmic side of the membrane to the extracellular space. The transport of protons is coupled to the transfer of energy from light, and there is no direct opening or pore formation in the membrane.

How Does Bacteriorhodopsin Couple Photoexcitation with Proton Pumping