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Shinya Tahara
Osaka University
13Publications
4H-index
62Citations
Publications 13
Newest
#1Shinya TaharaH-Index: 4
#2Hikaru Kuramochi (National Presto Industries)H-Index: 6
Last.Tahei TaharaH-Index: 38
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Bacteriorhodopsin is a prototypical photoreceptor protein that functions as a light-driven proton pump. The retinal chromophore of bacteriorhodopsin undergoes C13═C14 trans-to-cis isomerization upon photoexcitation, and it has been believed to be the first event that triggers the cascaded structural changes in bacteriorhodopsin. We investigated the protein dynamics of bacteriorhodopsin using deep-ultraviolet resonance femtosecond stimulated Raman spectroscopy. It was found that the stimulated Ra...
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#1Shinya Tahara (Osaka University)H-Index: 4
#2Manish Singh (Nagoya Institute of Technology)H-Index: 3
Last.Tahei TaharaH-Index: 38
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Heliorhodopsins (HeR) constitute a new rhodopsin family and show only 650 nm region, and these transient signals decay concomitantly with appearance of photoproduct absorption on a subpicosecond time scale. The observed spectral change indicates that ultrafast retinal photoisomerization proceeds in the femtosecond time region. The transient spectra and dynamics of HeRs are surprisingly similar to those of type-1 rhodopsins, despite remarkable differences in amino acid arrangement in...
2 CitationsSource
#1Keiichi Inoue (National Presto Industries)H-Index: 21
#2Shinya TaharaH-Index: 4
Last.Hideki KandoriH-Index: 41
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Parvularcula oceani xenorhodopsin is the first light-driven inward proton pump. To understand the mechanism of inward proton transport, comprehensive transient absorption spectroscopy was conducted. Ultrafast pump–probe spectroscopy revealed that the isomerization time of retinal is 1.2 ps, which is considerably slower than those of other microbial rhodopsins (180–770 fs). Following the production of J, the K intermediate was formed at 4 ps. Proton transfer occurred on a slower timescale. Proton...
1 CitationsSource
#1Shinya TaharaH-Index: 4
#2Satoshi TakeuchiH-Index: 22
Last.Tahei TaharaH-Index: 38
view all 7 authors...
KR2 is the first light-driven Na+-pumping rhodopsin discovered. It was reported that the photoexcitation of KR2 generates multiple S1 states, i.e., “reactive” and “nonreactive” S1 states at physiological pH, but their origin remained unclear. In this study, we examined the S1 state dynamics of KR2 using femtosecond time-resolved absorption spectroscopy at different pH′s in the range from 4 to 11. It was found that the reactive S1 state is predominantly formed at pH >9, but its population drastic...
2 CitationsSource
#1Shinya TaharaH-Index: 4
#2Satoshi TakeuchiH-Index: 22
Last.Tahei TaharaH-Index: 38
view all 7 authors...
KR2 is the first light-driven Na⁺-pumping rhodopsin discovered. It was reported that the photoexcitation of KR2 generates multiple S₁ states, i.e., “reactive” and “nonreactive” S₁ states at physiological pH, but their origin remained unclear. In this study, we examined the S₁ state dynamics of KR2 using femtosecond time-resolved absorption spectroscopy at different pH′s in the range from 4 to 11. It was found that the reactive S₁ state is predominantly formed at pH >9, but its population drastic...
#1Akiko Niho (Okayama University)H-Index: 1
#2Susumu Yoshizawa (UTokyo: University of Tokyo)H-Index: 12
Last.Yuki SudoH-Index: 27
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In organisms, ion transporters play essential roles in the generation and dissipation of ion gradients across cell membranes. Microbial rhodopsins selectively transport cognate ions using solar energy, in which the substrate ions identified to date have been confined to monovalent ions such as H+, Na+, and Cl–. Here we report a novel rhodopsin from the cyanobacterium Synechocystis sp. PCC 7509, which inwardly transports a polyatomic divalent sulfate ion, SO42–, with changes of its spectroscopic ...
9 CitationsSource
#1Shinya TaharaH-Index: 4
#2Satoshi TakeuchiH-Index: 22
Last.Tahei TaharaH-Index: 38
view all 4 authors...
Real-time observation of nuclear motion during chemical reactions is crucial. Femtosecond near-infrared stimulated-Raman spectra of an isomerizing cyanine are drastically different from visible ones, reflecting the ultrafast wavepacket migration and spreading in the excited state.
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We report the first femtosecond time-resolved absorption study on ultrafast photoreaction dynamics of a recently discovered retinal protein, KR2, which functions as a light-driven sodium-ion pump. The obtained data show that the excited-state absorption around 460 nm and the stimulated emission around 720 nm decay concomitantly with a time constant of 180 fs. This demonstrates that the deactivation of the S1 state of KR2, which involves isomerization of the retinal chromophore, takes place three...
13 CitationsSource
#1Shinya TaharaH-Index: 4
#2Yoshitaka KatoH-Index: 8
Last.Hiroyuki OhtaniH-Index: 16
view all 4 authors...
Anabaena sensory rhodopsin (ASR) is well-known as the only retinal protein that achieves the photochromic reaction between the all-trans form (AT-ASR) and the 13-cis form (C-ASR). Although it is known that the structure of the hydrogen-bonding network of ASR is pH-dependent, it is so far unclear how pH affects the photoreaction of ASR. We investigated the pH dependence of the photoreaction of AT-ASR by means of time-resolved absorption spectroscopy and found it to be extremely dependent on pH. A...
5 CitationsSource
#1Shinya TaharaH-Index: 4
#2Yoshitaka KatoH-Index: 8
Last.Hiroyuki OhtaniH-Index: 16
view all 4 authors...
Anabaena sensory rhodopsin (ASR) is well-known as the only retinal protein that achieves the photochromic reaction between the all-trans form (AT-ASR) and the 13-cis form (C-ASR). Although it is known that the structure of the hydrogen-bonding network of ASR is pH-dependent, it is so far unclear how pH affects the photoreaction of ASR. We investigated the pH dependence of the photoreaction of AT-ASR by means of time-resolved absorption spectroscopy and found it to be extremely dependent on pH. A...
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