bakteriorodopsyna

Bakteriorodopsyna is a protein found in the cell membrane of certain archaea, most notably Halobacterium salinarum. It functions as a light-driven proton pump. When it absorbs light, bacteriorhodopsin undergoes a series of conformational changes that lead to the translocation of protons across the cell membrane, from the cytoplasm to the extracellular space. This proton gradient is then used by the organism to generate ATP, the cell's primary energy currency, through a process called chemiosmosis.

The structure of bacteriorhodopsin is a seven-transmembrane helix protein, a common motif found in many membrane proteins. It contains a retinal molecule, a chromophore derived from vitamin A, which is covalently bound to a lysine residue within the protein. The absorption of light by retinal initiates the photocycle, a series of intermediate states that ultimately result in proton transport. The efficiency and mechanism of this light-driven proton pumping have made bacteriorhodopsin a model system for studying membrane protein function and energy transduction. Its discovery and subsequent characterization provided crucial insights into how light energy can be directly converted into chemical energy in biological systems, independent of photosynthesis.