Plastic model of the Bacteriorhodopsin 21 000 000:1

Bacteriorhodopsin is a proton pump protein, found in Halobacteria, members of Archaea group. It uses energy of light to transfer protons through the archebacterial membrane. The resulting proton gradient is subsequently converted into chemical energy. Bacteriorhodopsin contains retinal molecule, that changes its’ conformation after absorbing a photon. After that the conformation of the whole protein is also alters and it captures a proton from cell cytoplasm and releases it in outer space.

Bacteriorhodopsin is an integral membrane protein that possess seven transmembrane alpha-helices. Bacteriorhodopsin belongs to the protein family, that is related to vertebrate rhodopsin, that sense light in the retina. But rhodopsin is not involved in proton transport.