Question

2 a. What is the function of Bacteriorhodopsin? b. Which cofactor does it carry? c. How would you classify Bacteriorhodopsin as a protein transporter? [Hint: is it uniporter, transporter, channel, active transporter etc.?]

Answer 1

• A rhodopsin protein of bacterial origin called bacteriorhodopsin .
• This is a heat stable and a protein that changes its structure depending upon the light wavelength.
• This protein usually found on to the membrane surface of bacteria. Halobacterium salenarium is a bacteria which is having this bacteriorhodopsin as a light sensitive protein on to their membrane surface.
• unique property of bacteriorhodopsin is it is very much sensitive to light and the wavelength of light , when it receives a particular light wavelength it changes its structure and then in another wavelength it changes its structure into something else. so it is having an array of different structures.

The function of bacteriorhodopsin is that it acts as a proton pump, that is it captures light energy and uses it to move protons across the membrane out of the cell. It is the retinal molecule that changes its conformational when absorbing a photon, resulting ina conformational change of the surrounding protein pumping action.