Comprehensive spectroscopic study on the transport mechanism of sodium pump rhodopsin

2016 Fiscal Year Final Research Report

• Project/Area Number: 26708001
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Physical chemistry
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: Inoue Keiichi 名古屋工業大学, 工学(系)研究科(研究院), 准教授 (90467001)
• Research Collaborator: Kandori Hideki 名古屋工業大学, 大学院工学研究科, 教授 (70202033) ; Yoshizumi Rei ; Kato Yoshitaka
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 微生物型ロドプシン / ナトリウムポンプ / レチナール / プロトン移動 / 光反応サイクル / フラッシュフォトリシス / X線結晶構造解析 / オプトジェネティクス

Outline of Final Research Achievements

In this study, we studied the Na+ transport mechanism of light-driven Na+ pump rhodopsin (NaR) by functional assay of amino-acid mutant, flash photolysis, FTIR and X-ray crystallographic analysis. The results revealed that the opening of the gate for Na+ uptake with H+ transfer from the Schiff-base of chromophore retinal to Asp116 after photo-excitation, and the following Na+ binding in the protein is important for Na+-transport function. The site-directed mutation of Na+-uptake site whose structure was revealed in the crystallographic analysis achieved the creation of novel K+ pump and Cs+ pumps. Furthermore, we identified new NaRs which show photocurrents more than two-times higher in mammalian cells compared to the previously reported NaR.

Free Research Field

物理化学、生物物理学