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Special Seminar-Prof. Kwang-Hwan Jung | Institute of Chemistry

Special Seminar-Prof. Kwang-Hwan Jung

Date: 
Mon, 10/12/201812:00-13:00
Location: 
Seminar Hall, Los Angeles Building
Lecturer: 
Prof. Kwang-Hwan Jung

Title: Characterization of Light-driven Proton/Cation/Anion Pumping Rhodopsins and their Application


Abstract: Rhodopsin is seven-transmembrane light-harvest protein that contains all-trans retinal as a chromophore. Recently, more than 8,000 microbial opsin homologues are identified from environmental genomics, DNA sequencing projects, and PCR using degenerated primers. It means that it is found with variety of ecological distribution. Even though their structural template is strongly similar, its minor modifications can produce very different functions – proton pumping in and out, chloride pumping in, channels, and sensory transduction. Recently, new cation/anion-pumping rhodopsins have been identified. This sodium/lithium and Cl- / SO3- pumping rhodopsins were isolated from flavobacteria at Donghae, Korea. We characterized their property using site-directed mutagenesis. We changed all charged residues to neutral amino acids and found four critical residues for cation pumping activity. In addition, we applied this cation pumping-out rhodopsin, proton pumping-in rhodopsin (Anabaena sensory rhodopsin D217E), and proton pumping-out rhodopsin PR & GR (Gloeobacter rhodopsin) for various animal and plant tissues. In addition, we constructed artificial cells that produced ATP inside the giant liposome and performed enzyme reaction and actin polymerization. Our results demonstrated that these rhodopsins can be widely applicable to control membrane potential, and influence salt resistance and even life span.