How Catalizes Azide Proton-Pumping in D96N Mutated Bacteriorhodopsin?
Bacteriorhodopsin (bR) from halobacterium salinarium converts light energy into chemical energy by pumping protons across the cytoplasmic membrane and thereby creating a proton gradient. The chromophor, all-trans-retinal, is covalently linked to one of the seven transmembrane helices via a protonated Schiff-base. After lightexcitation the chromophore isomerizes and the protein undergoes a photocycle during which one proton is transferred to the extracellular side. Using timeresolved FTIR-techniques two aspartic residues have been identified to be crucial for proton-pumping . D85 works as internal proton-acceptor receiving a proton from the Schiffbase and D96 works as internal proton-donor to the Schiflbase.
KeywordsChemical Energy Light Energy Cytoplasmic Membrane Transmembrane Helix Proton Gradient
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