A New Subfamily of Bacteriorhodopsin Participates In Converting Light Into Bioenergy Under Acidic Condition
Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taiwan
Bacteriorhodopsin proteins are light-driven proton pumps feature a seven-transmembrane α-helical region with a lysine-bound retinal that serves as a chromophore responsive to light . These BR proteins respond to ~550 nm light and exert outward proton pumping, resulting in a proton gradient in the extracellular region and consequently facilitate the inflow of protons back into the cell through ATP synthase to generate ATP. Most BR proteins are not optically stable and non-functional under acidic conditions. In 2013, we reported a BR from Haloarcula marismortui, HmBRII [2,3], showed high optical stability in acidic conditions even down to pH of 1.6 and maintained its light-driven proton pumping activity at pH of 4.0. Later in 2015, we identified another BR from...