The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Hideki Kandori - One of the best experts on this subject based on the ideXlab platform.
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distortIon and a strong hydrogen bond in the retinal chromophore enable sodium Ion transport by the sodium Ion Pump kr2
Journal of Physical Chemistry B, 2019Co-Authors: Nao Nishimura, Hideki Kandori, Misao Mizuno, Yasuhisa MizutaniAbstract:We conducted a comprehensive time-resolved resonance Raman spectroscopy study of the structures of the retinal chromophore during the photocycle of the sodium-Ion Pump Krokinobacter rhodopsin 2 (KR2). We succeeded in determining the structure of the chromophore in the unphotolyzed state and in the K, L, M, and O intermediates, by overcoming the problem that only a small fractIon of the M intermediate is accumulated in the KR2 photocycle. The Schiff base in the retinal chromophore forms a strong hydrogen bond in the unphotolyzed state and in the K, L, and O intermediates and is deprotonated in the M intermediate. FormatIon of this strong hydrogen bond facilitates deprotonatIon of the Schiff base, which is necessary for the sodium Ion to move past the Schiff base. The polyene chain in the chromophore of KR2 is twisted in all of the states of the photocycle: the portIon near the Schiff base is largely twisted in the unphotolyzed state and in the K intermediate, whereas the middle portIon of the polyene chain...
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solid state nuclear magnetic resonance structural study of the retinal binding pocket in sodium Ion Pump rhodopsin
Biochemistry, 2017Co-Authors: Arisu Shigeta, Keiichi Inoue, Hideki Kandori, Shota Ito, Takashi Okitsu, Akimori Wada, Izuru KawamuraAbstract:The recently identified Krokinobacter rhodopsin 2 (KR2) functIons as a light-driven sodium Ion Pump. The structure of the retinal-binding pocket of KR2 offers important insights into the mechanisms of KR2, which has motif of Asn112, Asp116, and Gln123 (NDQ) that is common among sodium Ion Pump rhodopsins but is unique among other microbial rhodopsins. Here we present solid-state nuclear magnetic resonance (NMR) characterizatIon of retinal and functIonally important residues in the vicinity of retinal in the ground state. We assigned chemical shifts of retinal C14 and C20 atoms, and Tyr218Cζ, Lys255Ce, and the protonated Schiff base of KR2 in lipid environments at acidic and neutral pH. 15N NMR signals of the protonated Schiff base showed a twist around the N–Ce bond under neutral conditIons, compared with other microbial rhodopsins. These data indicated that the locatIon of the counterIon Asp116 is one helical pitch toward the cytoplasmic side. In acidic environments, the 15N Schiff base signal was shifte...
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Spectroscopic Study of a Light-Driven Chloride Ion Pump from Marine Bacteria
Journal of Physical Chemistry B, 2014Co-Authors: Keiichi Inoue, Rei Abe-yoshizumi, Faisal Hammad Mekky Koua, Yoshitaka Kato, Hideki KandoriAbstract:Thousands of light-driven proton-Pumping rhodopsins have been found in marine microbes, and a light-driven sodium-Ion Pumping rhodopsin was recently discovered, which utilizes sunlight for the energy source of the cell. Similarly, a light-driven chloride-Ion Pump has been found from marine bacteria, and three eubacterial light-driven Pumps possess the DTE (proton Pump), NDQ (sodium-Ion Pump), and NTQ (chloride-Ion Pump) motifs corresponding to the D85, T89, and D96 positIons in bacteriorhodopsin (BR). The corresponding motif of the known haloarchaeal chloride-Ion Pump, halorhodopsin (HR), is TSA, which is entirely different from the NTQ motif of a eubacterial chloride-Ion Pump. It is thus intriguing to compare the molecular mechanism of these two chloride-Ion Pumps. Here we report the spectroscopic study of Fulvimarina rhodopsin (FR), a eubacterial light-driven chloride-Ion Pump from marine bacterium. FR binds a chloride-Ion near the retinal chromophore and chloride-Ion binding causes a spectral blue-shif...
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A light-driven sodium Ion Pump in marine bacteria
Nature Communications, 2013Co-Authors: Keiichi Inoue, Hikaru Ono, Rei Abe-yoshizumi, Kazuhiro Kogure, Susumu Yoshizawa, Hiroyasu Ito, Hideki KandoriAbstract:Light-driven proton-Pumping rhodopsins are widely distributed in many microorganisms. They convert sunlight energy into proton gradients that serve as energy source of the cell. Here we report a new functIonal class of a microbial rhodopsin, a light-driven sodium Ion Pump. We discover that the marine flavobacterium Krokinobacter eikastus possesses two rhodopsins, the first, KR1, being a prototypical proton Pump, while the second, KR2, Pumps sodium Ions outward. Rhodopsin KR2 can also Pump lithium Ions, but converts to a proton Pump when presented with potassium chloride or salts of larger catIons. These data indicate that KR2 is a compatible sodium Ion-proton Pump, and spectroscopic analysis showed it binds sodium Ions in its extracellular domain. These findings suggest that light-driven sodium Pumps may be as important in situ as their proton-Pumping counterparts.
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ConversIon of bacteriorhodopsin into a chloride Ion Pump.
Science, 1995Co-Authors: Jun Sasaki, Hideki Kandori, Leonid S. Brown, Young-shin Chon, Akio Maeda, Richard Needleman, Janos K LanyiAbstract:In the light-driven proton Pump bacteriorhodopsin, proton transfer from the retinal Schiff base to aspartate-85 is the crucial reactIon of the transport cycle. In halorhodopsin, a light-driven chloride Ion Pump, the equivalent of residue 85 is threonine. When aspartate-85 was replaced with threonine, the mutated bacteriorhodopsin became a chloride Ion Pump when expressed in Halobacterium salinarium and, like halorhodopsin, actively transported chloride Ions in the directIon opposite from the proton Pump. Chloride was bound to it, as revealed by large shifts of the absorptIon maximum of the chromophore, and its photointermediates included a red-shifted state in the millisecond time domain, with its amplitude and decay rate dependent on chloride concentratIon. Bacteriorhodopsin and halorhodopsin thus share a common transport mechanism, and the interactIon of residue 85 with the retinal Schiff base determines the Ionic specificity.
Keiichi Inoue - One of the best experts on this subject based on the ideXlab platform.
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solid state nuclear magnetic resonance structural study of the retinal binding pocket in sodium Ion Pump rhodopsin
Biochemistry, 2017Co-Authors: Arisu Shigeta, Keiichi Inoue, Hideki Kandori, Shota Ito, Takashi Okitsu, Akimori Wada, Izuru KawamuraAbstract:The recently identified Krokinobacter rhodopsin 2 (KR2) functIons as a light-driven sodium Ion Pump. The structure of the retinal-binding pocket of KR2 offers important insights into the mechanisms of KR2, which has motif of Asn112, Asp116, and Gln123 (NDQ) that is common among sodium Ion Pump rhodopsins but is unique among other microbial rhodopsins. Here we present solid-state nuclear magnetic resonance (NMR) characterizatIon of retinal and functIonally important residues in the vicinity of retinal in the ground state. We assigned chemical shifts of retinal C14 and C20 atoms, and Tyr218Cζ, Lys255Ce, and the protonated Schiff base of KR2 in lipid environments at acidic and neutral pH. 15N NMR signals of the protonated Schiff base showed a twist around the N–Ce bond under neutral conditIons, compared with other microbial rhodopsins. These data indicated that the locatIon of the counterIon Asp116 is one helical pitch toward the cytoplasmic side. In acidic environments, the 15N Schiff base signal was shifte...
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Spectroscopic Study of a Light-Driven Chloride Ion Pump from Marine Bacteria
Journal of Physical Chemistry B, 2014Co-Authors: Keiichi Inoue, Rei Abe-yoshizumi, Faisal Hammad Mekky Koua, Yoshitaka Kato, Hideki KandoriAbstract:Thousands of light-driven proton-Pumping rhodopsins have been found in marine microbes, and a light-driven sodium-Ion Pumping rhodopsin was recently discovered, which utilizes sunlight for the energy source of the cell. Similarly, a light-driven chloride-Ion Pump has been found from marine bacteria, and three eubacterial light-driven Pumps possess the DTE (proton Pump), NDQ (sodium-Ion Pump), and NTQ (chloride-Ion Pump) motifs corresponding to the D85, T89, and D96 positIons in bacteriorhodopsin (BR). The corresponding motif of the known haloarchaeal chloride-Ion Pump, halorhodopsin (HR), is TSA, which is entirely different from the NTQ motif of a eubacterial chloride-Ion Pump. It is thus intriguing to compare the molecular mechanism of these two chloride-Ion Pumps. Here we report the spectroscopic study of Fulvimarina rhodopsin (FR), a eubacterial light-driven chloride-Ion Pump from marine bacterium. FR binds a chloride-Ion near the retinal chromophore and chloride-Ion binding causes a spectral blue-shif...
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A light-driven sodium Ion Pump in marine bacteria
Nature Communications, 2013Co-Authors: Keiichi Inoue, Hikaru Ono, Rei Abe-yoshizumi, Kazuhiro Kogure, Susumu Yoshizawa, Hiroyasu Ito, Hideki KandoriAbstract:Light-driven proton-Pumping rhodopsins are widely distributed in many microorganisms. They convert sunlight energy into proton gradients that serve as energy source of the cell. Here we report a new functIonal class of a microbial rhodopsin, a light-driven sodium Ion Pump. We discover that the marine flavobacterium Krokinobacter eikastus possesses two rhodopsins, the first, KR1, being a prototypical proton Pump, while the second, KR2, Pumps sodium Ions outward. Rhodopsin KR2 can also Pump lithium Ions, but converts to a proton Pump when presented with potassium chloride or salts of larger catIons. These data indicate that KR2 is a compatible sodium Ion-proton Pump, and spectroscopic analysis showed it binds sodium Ions in its extracellular domain. These findings suggest that light-driven sodium Pumps may be as important in situ as their proton-Pumping counterparts.
Izuru Kawamura - One of the best experts on this subject based on the ideXlab platform.
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solid state nuclear magnetic resonance structural study of the retinal binding pocket in sodium Ion Pump rhodopsin
Biochemistry, 2017Co-Authors: Arisu Shigeta, Keiichi Inoue, Hideki Kandori, Shota Ito, Takashi Okitsu, Akimori Wada, Izuru KawamuraAbstract:The recently identified Krokinobacter rhodopsin 2 (KR2) functIons as a light-driven sodium Ion Pump. The structure of the retinal-binding pocket of KR2 offers important insights into the mechanisms of KR2, which has motif of Asn112, Asp116, and Gln123 (NDQ) that is common among sodium Ion Pump rhodopsins but is unique among other microbial rhodopsins. Here we present solid-state nuclear magnetic resonance (NMR) characterizatIon of retinal and functIonally important residues in the vicinity of retinal in the ground state. We assigned chemical shifts of retinal C14 and C20 atoms, and Tyr218Cζ, Lys255Ce, and the protonated Schiff base of KR2 in lipid environments at acidic and neutral pH. 15N NMR signals of the protonated Schiff base showed a twist around the N–Ce bond under neutral conditIons, compared with other microbial rhodopsins. These data indicated that the locatIon of the counterIon Asp116 is one helical pitch toward the cytoplasmic side. In acidic environments, the 15N Schiff base signal was shifte...
Lei Jiang - One of the best experts on this subject based on the ideXlab platform.
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Artificial light-driven Ion Pump for photoelectric energy conversIon
Nature Communications, 2019Co-Authors: Kai Xiao, Lei Jiang, Lu Chen, Ruotian Chen, Tobias Heil, Saul Daniel Cruz Lemus, Fengtao Fan, Liping Wen, Markus AntoniettiAbstract:Biological light-driven Ion Pumps move Ions against a concentratIon gradient to create a membrane potential, thus converting sunlight energy directly into an osmotic potential. Here, we describe an artificial light-driven Ion Pump system in which a carbon nitride nanotube membrane can drive Ions thermodynamically uphill against an up to 5000-fold concentratIon gradient by illuminatIon. The separatIon of electrons and holes in the membrane under illuminatIon results in a transmembrane potential which is thought to be the foundatIon for the Pumping phenomenon. When used for harvesting solar energy, a sustained open circuit voltage of 550 mV and a current density of 2.4 μA/cm2 can reliably be generated, which can be further scaled up through series and parallel circuits of multiple membranes. The Ion transport based photovoltaic system proposed here offers a roadmap for the development of devices by using simple, cheap, and stable polymeric carbon nitride. Biological light-driven Ion Pumps move Ions against a concentratIon gradient to create a membrane potential, converting sunlight into an osmotic potential. Here, the authors make an artificial Ion Pump which drives Ions thermodynamically uphill against a large concentratIon gradient upon illuminatIon, which can be used for harvesting solar energy.
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bioinspired heterogeneous Ion Pump membranes unidirectIonal selective Pumping and controllable gating properties stemming from asymmetric Ionic group distributIon
Journal of the American Chemical Society, 2018Co-Authors: Zhen Zhang, Ye Tian, Pei Li, Xiangyu Kong, Yongchao Qian, Ziqi Wang, Lei JiangAbstract:The creatIon of an artificial solid-state Ion Pump that mimics the delicate Ion transport behaviors of a biological protein-based Ion Pump is drawing more and more research attentIon due to its potential applicatIons in energy conversIon, biosensor, and desalinatIon. However, the reported bioinspired double-gated Ion Pump systems are generally very primary and can only realize nonselective Ion Pumping functIons with no directIonality and uncontrollable Ion gating functIons, which are far from their biological counterparts. To make the bioinspired device “smart” in a real sense, the implementatIon of high-level selectivity and directIonality in the Ion Pumping process, while achieving great controllability in the Ion gating process, is a necessity. Here, we developed a bioinspired heterogeneous Ion Pump membrane by combining block copolymer membrane sacrificial coating and plasma grafting technique. The system has unidirectIonal selective Ion Pumping and controllable Ion gating properties. The introductIon...
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uphill catIon transport a bioinspired photo driven Ion Pump
Science Advances, 2016Co-Authors: Zhen Zhang, Pei Li, Xiangyu Kong, Kai Xiao, Lei JiangAbstract:Biological Ion Pumps with active Ionic transport properties lay the foundatIon for many life processes. However, few analogs have been produced because extra energy is needed to couple to this “uphill” process. We demonstrate a bioinspired artificial photo-driven Ion Pump based on a single polyethylene terephthalate conical nanochannel. The Pumping process behaving as an inversIon of zero-volt current can be realized by applying ultraviolet irradiatIon from the large opening. The light energy can accelerate the dissociatIon of the benzoic acid derivative dimers existing on the inner surface of nanochannel, which consequently produces more mobile carboxyl groups. Enhanced electrostatic interactIon between the Ions traversing the nanochannel and the charged groups on the inner wall is the key reason for the uphill catIon transport behavior. This system creates an ideal experimental and theoretical platform for further development and design of various stimuli-driven and specific Ion–selective bioinspired Ion Pumps, which anticipates wide potential applicatIons in biosensing, energy conversIon, and desalinatIon.
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Bioinspired artificial single Ion Pump.
Journal of the American Chemical Society, 2013Co-Authors: Huacheng Zhang, Xu Hou, Lu Zeng, Fu Yang, Dadong Yan, Ye Tian, Lei JiangAbstract:Bioinspired artificial functIonal nanochannels for intelligent molecular and Ionic transport control at the nanoscale have wide potential applicatIons in nanofluidics, energy conversIon, and biosensors. Although various smart passive Ion transport properties of Ion channels have been artificially realized, it is still hugely challenging to achieve high level intelligent Ion transport features in biological Ion Pumps. Here we show a unique bioinspired single Ion Pump based on a cooperative pH response double-gate nanochannel, whose gates could be opened and closed alternately/simultaneously under symmetric/asymmetric pH environments. With the stimulatIon of the double-gate nanochannel by continuous switching of the symmetric/asymmetric pH stimuli, the bioinspired system systematically realized three key Ionic transport features of biological Ion Pumps, including an alternating gates Ion Pumping process under symmetric pH stimuli, transformatIon of the Ion Pump into an Ion channel under asymmetric pH stimul...
Nicolas Reyes - One of the best experts on this subject based on the ideXlab platform.
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peering into an atpase Ion Pump with single channel recordings
Philosophical Transactions of the Royal Society B, 2009Co-Authors: David C Gadsby, Ayako Takeuchi, Pablo Artigas, Nicolas ReyesAbstract:In principle, an Ion channel needs no more than a single gate, but a Pump requires at least two gates that open and close alternately to allow Ion access from only one side of the membrane at a time. In the Na+,K+-ATPase Pump, this alternating gating effects outward transport of three Na+ Ions and inward transport of two K+ Ions, for each ATP hydrolysed, up to a hundred times per second, generating a measurable current if assayed in millIons of Pumps. Under these assay conditIons, voltage jumps elicit brief charge movements, consistent with displacement of Ions along the Ion pathway while one gate is open but the other closed. Binding of the marine toxin, palytoxin, to the Na+,K+-ATPase uncouples the two gates, so that although each gate still responds to its physiological ligand they are no longer constrained to open and close alternately, and the Na+,K+-ATPase is transformed into a gated catIon channel. MillIons of Na+ or K+ Ions per second flow through such an open Pump–channel, permitting assay of single molecules and allowing unprecedented access to the Ion transport pathway through the Na+,K+-ATPase. Use of variously charged small hydrophilic thiol-specific reagents to probe cysteine targets introduced throughout the Pump's transmembrane segments allows mapping and characterizatIon of the route traversed by transported Ions.
