Modulating the lifetime of the charge-separated state in photosynthetic reaction center by out-of-protein electrostatics

The photosynthetic reaction center (RC) is an integral membrane protein that, upon absorption of photons, generates a hole-electron couple with a yield close to one. This energetic state has numerous possible applications in several biotechnological fields given that its lifetime is long enough to allow non-metabolic ancillary redox chemistry to take place. Here we focus on RCs reconstituted in liposomes, formed with sole phospholipids or in blends with other lipids, and show that the electrical charge sitting on the polar head of such hydrophobic molecules does play an important role on the stability of the hole-electron couple. More specifically this study shows that the presence of negative charges in the surrounding of the protein stabilizes the charge-separated state while positive charges have a strong opposite effect.