2016年8月
The Study on a Novel Light-driven Sodium Pump and Creation of New Functional Molecules
Molecular Science
- 巻
- 10
- 号
- 1
- 開始ページ
- AA0086
- 終了ページ
- 記述言語
- 英語
- 掲載種別
- 記事・総説・解説・論説等(学術雑誌)
- DOI
- 10.3175/molsci.10.A0086
- 出版者・発行元
- 分子科学会
Microbial rhodopsin is a photo-receptive membrane protein of micro-organisms. The most ubiquitous microbial rhodopsins are light-driven ion pumps which actively transport H+ or Cl- against membrane chemical potential. In 2013, we reported a new class of ion pump rhodopsin, sodium pump rhodopsin (KR2) which outwardly transports Na+ ion by the use of light energy. The mechanism of Na+ transport by KR2 was investigated in spectroscopic and crystallographic studies. The results showed that the H+ transfer between photoisomerized retinal Schiff base and its counter ion, Asp116, is a critical process for the Na+-transport function. After this H+ transfer, the protonated Asp116 sequesters the H+ from the ion-transport pathway, and then immediately Na+ is taken up from the cytoplasmic side. The Na+ binds to the site composed of Asn112 and Asp251, and simultaneously H+ goes back to the retinal Schiff base. Then, positive charge of the reprotonated retinal Schiff-base prevents the back flow of Na+ to the cytoplasmic side. Finally, the Na+ is released to the extracellular side. Furthermore, on the basis of structural insights about KR2, we have succeeded to develop new artificial K+ and Cs+ pumping KR2 mutants, KR2K+ and KR2Cs+, respectively. Wildtype KR2 and these mutants are expected to provide new ways of the application to optogenetics.
- リンク情報
- ID情報
-
- DOI : 10.3175/molsci.10.A0086
- CiNii Articles ID : 130005263099