Molecular properties of a DTD channelrhodopsin from <i>Guillardia theta</i>

DOI Web Site 14 Citations 9 References
  • Yamauchi Yumeka
    Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
  • Konno Masae
    Department of Life Science and Applied Chemistry, Nagoya Institute of Technology OptoBioTechnology Research Center, Nagoya Institute of Technology
  • Ito Shota
    Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
  • Tsunoda Satoshi P.
    Department of Life Science and Applied Chemistry, Nagoya Institute of Technology OptoBioTechnology Research Center, Nagoya Institute of Technology PRESTO, Japan Science and Technology Agency
  • Inoue Keiichi
    Department of Life Science and Applied Chemistry, Nagoya Institute of Technology OptoBioTechnology Research Center, Nagoya Institute of Technology PRESTO, Japan Science and Technology Agency Frontier Research Institute for Material Science, Nagoya Institute of Technology
  • Kandori Hideki
    Department of Life Science and Applied Chemistry, Nagoya Institute of Technology OptoBioTechnology Research Center, Nagoya Institute of Technology

Bibliographic Information

Other Title
  • Molecular properties of a DTD channelrhodopsin from Guillardia theta

Abstract

<p>Microbial rhodopsins are membrane proteins found widely in archaea, eubacteria and eukaryotes (fungal and algal species). They have various functions, such as light-driven ion pumps, light-gated ion channels, light sensors and light-activated enzymes. A light-driven proton pump bacteriorhodopsin (BR) contains a DTD motif at positions 85, 89, and 96, which is unique to archaeal proton pumps. Recently, channelrhodopsins (ChRs) containing the DTD motif, whose sequential identity is ~20% similar to BR and to cation ChRs in Chlamydomonas reinhardtii (CrCCRs), were found. While extensive studies on ChRs have been performed with CrCCR2, the molecular properties of DTD ChRs remain an intrigue. In this paper, we studied a DTD rhodopsin from G. theta (GtCCR4) using electrophysiological measurements, flash photolysis, and low-temperature difference FTIR spectroscopy. Electrophysiological measurements clearly showed that GtCCR4 functions as a light-gated cation channel, similar to other G. theta DTD ChRs (GtCCR1-3). Light-driven proton pump activity was also suggested for GtCCR4. Both electrophysiological and flash photolysis experiments showed that channel closing occurs upon reprotonation of the Schiff base, suggesting that the dynamics of retinal and channels are tightly coupled in GtCCR4. From Fourier transform infrared (FTIR) spectroscopy at 77 K, we found that the primary reaction is an all-trans to a 13-cis photoisomerization, like other microbial rhodopsins, although perturbations in the secondary structure were much smaller in GtCCR4 than in CrCCR2.</p>

Journal

Citations (14)*help

See more

References(9)*help

See more

Related Projects

See more

Keywords

Details 詳細情報について

Report a problem

Back to top