Monomeric and Aggregated Bacteriorhodopsin : single-Turnover Proton Transport Stoichiometry and Photochemistry

摘要: Abstract The question of the basic functional transport unit bacteriorhodopsin (BR) has been addressed by comparing proton pumping stoichiometry as well photocycle kinetics monomeric and aggregated BR in phospholipid vesicles. When time-resolved laser spectroscopy was used combination with optical pH-indicator pyranine, single-turnover experiments revealed approximately 0.5-0.8 0.8-1.2 protons vectorially translocated per photocycling molecule, respectively. Since both these values are akin very similar to crystalline molecules purple membrane, monomer proven be essential unit. The natural arrangement photopigments a array immobilized trimers is not required for efficient vectorial translocation.