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Singh M, Ito S, Hososhima S, Abe-Yoshizumi R, Tsunoda SP, Inoue K, Kandori H. Light-Driven Chloride and Sulfate Pump with Two Different Transport Modes. J Phys Chem B 2023; 127:7123-7134. [PMID: 37552856 DOI: 10.1021/acs.jpcb.3c02116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Ion pumps are membrane proteins that actively translocate ions by using energy. All known pumps bind ions in the resting state, and external energy allows ion transport through protein structural changes. The light-driven sodium-ion pump Krokinobacter eikastus rhodopsin 2 (KR2) is an exceptional case in which ion binding follows the energy input. In this study, we report another case of this unusual transport mode. The NTQ rhodopsin from Alteribacter aurantiacus (AaClR) is a natural light-driven chloride pump, in which the chloride ion binds to the resting state. AaClR is also able to pump sulfate ions, though the pump efficiency is much lower for sulfate ions than for chloride ions. Detailed spectroscopic analysis revealed no binding of the sulfate ion to the resting state of AaClR, indicating that binding of the substrate (sulfate ion) to the resting state is not necessary for active transport. This property of the AaClR sulfate pump is similar to that of the KR2 sodium pump. Photocycle dynamics of the AaClR sulfate pump resemble a non-functional cycle in the absence of anions. Despite this, flash photolysis and difference Fourier transform infrared spectroscopy suggest transient binding of the sulfate ion to AaClR. The molecular mechanism of this unusual active transport by AaClR is discussed.
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Affiliation(s)
- Manish Singh
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Shota Ito
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Rei Abe-Yoshizumi
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Satoshi P Tsunoda
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-855, Japan
| | - Keiichi Inoue
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-855, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-855, Japan
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2
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Weissbecker J, Boumrifak C, Breyer M, Wießalla T, Shevchenko V, Mager T, Slavov C, Alekseev A, Kovalev K, Gordeliy V, Bamberg E, Wachtveitl J. Die spannungsabhängige Richtung der Reprotonierung der Schiff'schen Base bestimmt das Einwärtspumpen von Xenorhodopsin. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Juliane Weissbecker
- Abteilung Biophysikalische Chemie Max-Planck-Institut für Biophysik Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Chokri Boumrifak
- Institut für Physikalische and Theoretische Chemie Goethe Universität Max-von-Laue-Straße 7 60438 Frankfurt am Main Deutschland
| | - Maximilian Breyer
- Abteilung Biophysikalische Chemie Max-Planck-Institut für Biophysik Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Tristan Wießalla
- Abteilung Biophysikalische Chemie Max-Planck-Institut für Biophysik Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Vitaly Shevchenko
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry) Forschungszentrum Jülich GmbH Wilhelm-Johnen-Straße 52425 Jülich Deutschland
| | - Thomas Mager
- Abteilung Biophysikalische Chemie Max-Planck-Institut für Biophysik Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Chavdar Slavov
- Institut für Physikalische and Theoretische Chemie Goethe Universität Max-von-Laue-Straße 7 60438 Frankfurt am Main Deutschland
| | - Alexey Alekseev
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry) Forschungszentrum Jülich GmbH Wilhelm-Johnen-Straße 52425 Jülich Deutschland
| | - Kirill Kovalev
- European Molecular Biology Laboratory Notkestraße 85 22607 Hamburg Deutschland
- Research Center for Molecular Mechanisms of Aging and Age-related Diseases Moscow Institute of Physics and Technology Dolgoprudny Russland
| | - Valentin Gordeliy
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry) Forschungszentrum Jülich GmbH Wilhelm-Johnen-Straße 52425 Jülich Deutschland
| | - Ernst Bamberg
- Abteilung Biophysikalische Chemie Max-Planck-Institut für Biophysik Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Josef Wachtveitl
- Institut für Physikalische and Theoretische Chemie Goethe Universität Max-von-Laue-Straße 7 60438 Frankfurt am Main Deutschland
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3
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Hososhima S, Kandori H, Tsunoda SP. Ion transport activity and optogenetics capability of light-driven Na+-pump KR2. PLoS One 2021; 16:e0256728. [PMID: 34506508 PMCID: PMC8432791 DOI: 10.1371/journal.pone.0256728] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 08/13/2021] [Indexed: 01/26/2023] Open
Abstract
KR2 from marine bacteria Krokinobacter eikastus is a light-driven Na+ pumping rhodopsin family (NaRs) member that actively transports Na+ and/or H+ depending on the ionic state. We here report electrophysiological studies on KR2 to address ion-transport properties under various electrochemical potentials of Δ[Na+], ΔpH, membrane voltage and light quality, because the contributions of these on the pumping activity were less understood so far. After transient expression of KR2 in mammalian cultured cells (ND7/23 cells), photocurrents were measured by whole-cell patch clamp under various intracellular Na+ and pH conditions. When KR2 was continuously illuminated with LED light, two distinct time constants were obtained depending on the Na+ concentration. KR2 exhibited slow ion transport (τoff of 28 ms) below 1.1 mM NaCl and rapid transport (τoff of 11 ms) above 11 mM NaCl. This indicates distinct transporting kinetics of H+ and Na+. Photocurrent amplitude (current density) depends on the intracellular Na+ concentration, as is expected for a Na+ pump. The M-intermediate in the photocycle of KR2 could be transferred into the dark state without net ion transport by blue light illumination on top of green light. The M intermediate was stabilized by higher membrane voltage. Furthermore, we assessed the optogenetic silencing effect of rat cortical neurons after expressing KR2. Light power dependency revealed that action potential was profoundly inhibited by 1.5 mW/mm2 green light illumination, confirming the ability to apply KR2 as an optogenetics silencer.
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Affiliation(s)
- Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
- OptoBio Technology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
| | - Satoshi P. Tsunoda
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
- * E-mail:
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4
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Wachtveitl J, Weissbecker J, Boumrifak C, Breyer M, Wießalla T, Shevchenko V, Mager T, Slavov C, Alekseev A, Kovalev K, Gordeliy V, Bamberg E. The voltage dependent sidedness of the reprotonation of the retinal Schiff base determines the unique inward pumping of Xenorhodopsin. Angew Chem Int Ed Engl 2021; 60:23010-23017. [PMID: 34339559 PMCID: PMC8518763 DOI: 10.1002/anie.202103882] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Indexed: 11/07/2022]
Abstract
The new class of microbial rhodopsins, called xenorhodopsins (XeRs) (1), extends the versatility of this family by inward H + pumps (2-4). These pumps are an alternative optogenetic tool to the light-gated ion channels (e.g. ChR1,2), because the activation of electrically excitable cells by XeRs is independent from the surrounding physiological conditions. In this work we functionally and spectroscopically characterized XeR from Nanosalina ( Ns XeR) (1). The photodynamic behavior of Ns XeR was investigated on the ps to s time scale elucidating the formation of the J and K and a previously unknown long-lived intermediate. The pH dependent kinetics reveal that alkalization of the surrounding medium accelerates the photocycle and the pump turnover. In patch-clamp experiments the blue-light illumination of Ns XeR in the M state shows a potential-dependent vectoriality of the photocurrent transients, suggesting a variable accessibility of reprotonation of the retinal Schiff base. Insights on the kinetically independent switching mechanism could furthermore be obtained by mutational studies on the putative intracellular H + acceptor D220.
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Affiliation(s)
- Josef Wachtveitl
- Goethe-Universität Frankfurt am Main, Physical and Theoretical Chemistry, Max von Laue-Straße 7, 60438, Frankfurt am Main, GERMANY
| | | | - Chokri Boumrifak
- Goethe-Universitat Frankfurt am Main, Biochemistry, Chemistry and Pharmacy, GERMANY
| | | | - Tristan Wießalla
- Max-Planck-Institut fur Biophysik, Biophysical Chemistry, GERMANY
| | - Vitaly Shevchenko
- Forschungszentrum Julich ICG: Forschungszentrum Julich GmbH, Biological Information Processing, GERMANY
| | - Thomas Mager
- Max Planck Institute of Biophysics: Max-Planck-Institut fur Biophysik, Biophysical Chemistry, GERMANY
| | - Chavdar Slavov
- Goethe-Universitat Frankfurt am Main, Chemistry, GERMANY
| | - Alexey Alekseev
- Forschungszentrum Jülich: Forschungszentrum Julich GmbH, Biological Information Processing, GERMANY
| | - Kirill Kovalev
- Forschungszentrum Jülich: Forschungszentrum Julich GmbH, Biological Information Processing, GERMANY
| | - Valentin Gordeliy
- Forschungszentrum Jülich: Forschungszentrum Julich GmbH, Biological Information Processing, GERMANY
| | - Ernst Bamberg
- Max-Planck-Institut fur Biophysik, Biophysical Chemistry, GERMANY
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5
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Fudim R, Szczepek M, Vierock J, Vogt A, Schmidt A, Kleinau G, Fischer P, Bartl F, Scheerer P, Hegemann P. Design of a light-gated proton channel based on the crystal structure of Coccomyxa rhodopsin. Sci Signal 2019; 12:12/573/eaav4203. [PMID: 30890657 DOI: 10.1126/scisignal.aav4203] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The light-driven proton pump Coccomyxa subellipsoidea rhodopsin (CsR) provides-because of its high expression in heterologous host cells-an opportunity to study active proton transport under controlled electrochemical conditions. In this study, solving crystal structure of CsR at 2.0-Å resolution enabled us to identify distinct features of the membrane protein that determine ion transport directivity and voltage sensitivity. A specific hydrogen bond between the highly conserved Arg83 and the nearby nonconserved tyrosine (Tyr14) guided our structure-based transformation of CsR into an operational light-gated proton channel (CySeR) that could potentially be used in optogenetic assays. Time-resolved electrophysiological and spectroscopic measurements distinguished pump currents from channel currents in a single protein and emphasized the necessity of Arg83 mobility in CsR as a dynamic extracellular barrier to prevent passive conductance. Our findings reveal that molecular constraints that distinguish pump from channel currents are structurally more confined than was generally expected. This knowledge might enable the structure-based design of novel optogenetic tools, which derive from microbial pumps and are therefore ion specific.
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Affiliation(s)
- Roman Fudim
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Michal Szczepek
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Johannes Vierock
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Arend Vogt
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Andrea Schmidt
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Gunnar Kleinau
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Paul Fischer
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Franz Bartl
- Biophysical Chemistry, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Patrick Scheerer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany.
| | - Peter Hegemann
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany.
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6
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Otrin L, Kleineberg C, Caire da Silva L, Landfester K, Ivanov I, Wang M, Bednarz C, Sundmacher K, Vidaković-Koch T. Artificial Organelles for Energy Regeneration. ACTA ACUST UNITED AC 2019; 3:e1800323. [PMID: 32648709 DOI: 10.1002/adbi.201800323] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/11/2019] [Indexed: 01/03/2023]
Abstract
One of the critical steps in sustaining life-mimicking processes in synthetic cells is energy, i.e., adenosine triphosphate (ATP) regeneration. Previous studies have shown that the simple addition of ATP or ATP regeneration systems, which do not regenerate ATP directly from ADP and Pi , have no or only limited success due to accumulation of ATP hydrolysis products. In general, ATP regeneration can be achieved by converting light or chemical energy into ATP, which may also involve redox transformations of cofactors. The present contribution provides an overview of the existing ATP regeneration strategies and the related nicotinamide adenine dinucleotide (NAD+ ) redox cycling, with a focus on compartmentalized systems. Special attention is being paid to those approaches where so-called artificial organelles are developed. They comprise a semipermeable membrane functionalized by biological or man-made components and employ external energy in the form of light or nutrients in order to generate a transmembrane proton gradient, which is further utilized for ATP synthesis.
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Affiliation(s)
- Lado Otrin
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, 39106, Magdeburg, Germany
| | - Christin Kleineberg
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, 39106, Magdeburg, Germany
| | - Lucas Caire da Silva
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Katharina Landfester
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Ivan Ivanov
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, 39106, Magdeburg, Germany
| | - Minhui Wang
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, 39106, Magdeburg, Germany
| | - Claudia Bednarz
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, 39106, Magdeburg, Germany
| | - Kai Sundmacher
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, 39106, Magdeburg, Germany
| | - Tanja Vidaković-Koch
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, 39106, Magdeburg, Germany
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Geng X, Dai G, Chao L, Wen D, Kikukawa T, Iwasa T. Two Consecutive Polar Amino Acids at the End of Helix E are Important for Fast Turnover of the Archaerhodopsin Photocycle. Photochem Photobiol 2018; 95:980-989. [PMID: 30548616 DOI: 10.1111/php.13072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 12/09/2018] [Indexed: 11/27/2022]
Abstract
Archaerhodopsins (ARs) is one of the members of microbial rhodopsins. Threonine 164 (T164) and serine 165 (S165) residues of the AR from Halorubrum sp. ejinoor (HeAR) are fully conserved in ARs, although they are far from the proton transfer channel and the retinal Schiff base, and are likely involved in a hydrogen-bonding network at the end of the Helix E where most microbial rhodopsins assume a "bent structure". In the present work, T164 and/or S165 were replaced with an alanine (A), and the photocycles of the mutants were analyzed with flash photolysis. The amino acid replacements caused profound changes to the photocycle of HeAR including prolonged photocycle, accelerated decay of M intermediate and appearance of additional two intermediates which were evident in T164A- and T164A/S165A-HeAR photocyles. These results suggest that although T164 and S165 are located at the far end of the photoactive center, these two amino acid residues are important for maintaining the fast turnover of the HeAR photocycle. The underlying molecular mechanisms are discussed in relation to hydrogen-bonding networks involving these two amino acids. Present study may arouse our interests to explore the functional role of the well-conserved "bent structure" in different types of microbial rhodopsin.
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Affiliation(s)
- Xiong Geng
- Division of Engineering, Muroran Institute of Technology, Muroran, Japan
| | - Gang Dai
- College of Chemistry and Environmental Science, Inner Mongolia Normal University, Hohhot, China
| | - Luomeng Chao
- College of Animal Science and Technology, Inner Mongolia University for The Nationalities, Tong Liao, China
| | - Durige Wen
- Division of Engineering, Muroran Institute of Technology, Muroran, Japan
| | - Takashi Kikukawa
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan.,Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
| | - Tatsuo Iwasa
- Division of Engineering, Muroran Institute of Technology, Muroran, Japan
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Tsunoda SP, Prigge M, Abe-Yoshizumi R, Inoue K, Kozaki Y, Ishizuka T, Yawo H, Yizhar O, Kandori H. Functional characterization of sodium-pumping rhodopsins with different pumping properties. PLoS One 2017; 12:e0179232. [PMID: 28749956 PMCID: PMC5531490 DOI: 10.1371/journal.pone.0179232] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 05/25/2017] [Indexed: 12/25/2022] Open
Abstract
Sodium pumping rhodopsins (NaRs) are a unique member of the microbial-type I rhodopsin family which actively transport Na+ and H+ depending on ionic condition. In this study, we surveyed 12 different NaRs from various sources of eubacteria for their electrophysiological as well as spectroscopic properties. In mammalian cells several of these NaRs exhibited a Na+ based pump photocurrent and four interesting candidates were chosen for further characterization. Voltage dependent photocurrent amplitudes revealed a membrane potential-sensitive turnover rate, indicating the presence of an electrically-charged intermediate(s) in the photocycle reaction. The NaR from Salinarimonas rosea DSM21201 exhibited a red-shifted absorption spectrum, and slower kinetics compared to the first described sodium pump, KR2. Although the ratio of Na+ to H+ ion transport varied among the NaRs we tested, the NaRs from Flagellimonas sp_DIK and Nonlabens sp_YIK_SED-11 showed significantly higher Na+ selectivity when compared to KR2. All four further investigated NaRs showed a functional expression in dissociated hippocampal neuron culture and hyperpolarizing activity upon light-stimulation. Additionally, all four NaRs allowed optical inhibition of electrically-evoked neuronal spiking. Although efficiency of silencing was 3–5 times lower than silencing with the enhanced version of the proton pump AR3 from Halorubrum sodomense, our data outlines a new approach for hyperpolarization of excitable cells without affecting the intracellular and extracellular proton environment.
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Affiliation(s)
- Satoshi P. Tsunoda
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Japan
| | - Matthias Prigge
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Rei Abe-Yoshizumi
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Japan
| | - Keiichi Inoue
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Japan
- Department of Frontier Materials, Nagoya Institute of Technology, Nagoya, Japan
| | - Yuko Kozaki
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Japan
| | - Toru Ishizuka
- Department of Developmental Biology and Neurosciences, Tohoku University Graduate School of Life Science, Sendai, Japan
| | - Hiromu Yawo
- Department of Developmental Biology and Neurosciences, Tohoku University Graduate School of Life Science, Sendai, Japan
| | - Ofer Yizhar
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Hideki Kandori
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Japan
- * E-mail:
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9
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Conversion of a light-driven proton pump into a light-gated ion channel. Sci Rep 2015; 5:16450. [PMID: 26597707 PMCID: PMC4657025 DOI: 10.1038/srep16450] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 10/14/2015] [Indexed: 12/19/2022] Open
Abstract
Interest in microbial rhodopsins with ion pumping activity has been revitalized in the context of optogenetics, where light-driven ion pumps are used for cell hyperpolarization and voltage sensing. We identified an opsin-encoding gene (CsR) in the genome of the arctic alga Coccomyxa subellipsoidea C-169 that can produce large photocurrents in Xenopus oocytes. We used this property to analyze the function of individual residues in proton pumping. Modification of the highly conserved proton shuttling residue R83 or its interaction partner Y57 strongly reduced pumping power. Moreover, this mutation converted CsR at moderate electrochemical load into an operational proton channel with inward or outward rectification depending on the amino acid substitution. Together with molecular dynamics simulations, these data demonstrate that CsR-R83 and its interacting partner Y57 in conjunction with water molecules forms a proton shuttle that blocks passive proton flux during the dark-state but promotes proton movement uphill upon illumination.
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10
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Tunuguntla RH, Bangar MA, Kim K, Stroeve P, Grigoropoulos C, Ajo-Franklin CM, Noy A. Bioelectronic light-gated transistors with biologically tunable performance. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:831-836. [PMID: 25410490 DOI: 10.1002/adma.201403988] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/13/2014] [Indexed: 06/04/2023]
Abstract
Light-activated bioelectronic silicon nanowire transistor devices are made by fusing proteoliposomes containing a bacteriorhodopsin (bR) proton pump onto the nanowire surface. Under green-light illumination, bR pumps protons toward the nanowire, and the pH gradient developed by the pump changes the transistor output. Furthermore, co-assembly of small biomolecules that alter the bilayer permeability to other ions can upregulate and downregulate the response of field-effect transistor devices.
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Affiliation(s)
- Ramya H Tunuguntla
- Biology and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, 94550, USA; Materials Science and Chemical Engineering Department, University of California Davis, Davis, California, 95616, USA; The Molecular Foundry, Materials Sciences Division and
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11
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García-Martínez J, Brunk M, Avalos J, Terpitz U. The CarO rhodopsin of the fungus Fusarium fujikuroi is a light-driven proton pump that retards spore germination. Sci Rep 2015; 5:7798. [PMID: 25589426 PMCID: PMC4295100 DOI: 10.1038/srep07798] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 12/18/2014] [Indexed: 12/29/2022] Open
Abstract
Rhodopsins are membrane-embedded photoreceptors found in all major taxonomic kingdoms using retinal as their chromophore. They play well-known functions in different biological systems, but their roles in fungi remain unknown. The filamentous fungus Fusarium fujikuroi contains two putative rhodopsins, CarO and OpsA. The gene carO is light-regulated, and the predicted polypeptide contains all conserved residues required for proton pumping. We aimed to elucidate the expression and cellular location of the fungal rhodopsin CarO, its presumed proton-pumping activity and the possible effect of such function on F. fujikuroi growth. In electrophysiology experiments we confirmed that CarO is a green-light driven proton pump. Visualization of fluorescent CarO-YFP expressed in F. fujikuroi under control of its native promoter revealed higher accumulation in spores (conidia) produced by light-exposed mycelia. Germination analyses of conidia from carO(-) mutant and carO(+) control strains showed a faster development of light-exposed carO(-) germlings. In conclusion, CarO is an active proton pump, abundant in light-formed conidia, whose activity slows down early hyphal development under light. Interestingly, CarO-related rhodopsins are typically found in plant-associated fungi, where green light dominates the phyllosphere. Our data provide the first reliable clue on a possible biological role of a fungal rhodopsin.
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Affiliation(s)
- Jorge García-Martínez
- Department of Genetics, Faculty of Biology, University of Seville, E-41012 Seville, Spain
| | - Michael Brunk
- Department of Biotechnology and Biophysics, Biocenter, Julius Maximilian University Würzburg, D-97074 Würzburg, Germany
| | - Javier Avalos
- Department of Genetics, Faculty of Biology, University of Seville, E-41012 Seville, Spain
| | - Ulrich Terpitz
- Department of Biotechnology and Biophysics, Biocenter, Julius Maximilian University Würzburg, D-97074 Würzburg, Germany
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Hou JH, Venkatachalam V, Cohen AE. Temporal dynamics of microbial rhodopsin fluorescence reports absolute membrane voltage. Biophys J 2014; 106:639-48. [PMID: 24507604 DOI: 10.1016/j.bpj.2013.11.4493] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 01/07/2023] Open
Abstract
Plasma membrane voltage is a fundamentally important property of a living cell; its value is tightly coupled to membrane transport, the dynamics of transmembrane proteins, and to intercellular communication. Accurate measurement of the membrane voltage could elucidate subtle changes in cellular physiology, but existing genetically encoded fluorescent voltage reporters are better at reporting relative changes than absolute numbers. We developed an Archaerhodopsin-based fluorescent voltage sensor whose time-domain response to a stepwise change in illumination encodes the absolute membrane voltage. We validated this sensor in human embryonic kidney cells. Measurements were robust to variation in imaging parameters and in gene expression levels, and reported voltage with an absolute accuracy of 10 mV. With further improvements in membrane trafficking and signal amplitude, time-domain encoding of absolute voltage could be applied to investigate many important and previously intractable bioelectric phenomena.
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Affiliation(s)
- Jennifer H Hou
- Department of Physics, Harvard University, Cambridge, Massachusetts
| | | | - Adam E Cohen
- Department of Physics, Harvard University, Cambridge, Massachusetts; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts.
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Wang T, Oppawsky C, Duan Y, Tittor J, Oesterhelt D, Facciotti MT. Stable closure of the cytoplasmic half-channel is required for efficient proton transport at physiological membrane potentials in the bacteriorhodopsin catalytic cycle. Biochemistry 2014; 53:2380-90. [PMID: 24660845 PMCID: PMC4004217 DOI: 10.1021/bi4013808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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The bacteriorhodopsin (BR) Asp96Gly/Phe171Cys/Phe219Leu
triple
mutant has been shown to translocate protons 66% as efficiently as
the wild-type protein. Light-dependent ATP synthesis in haloarchaeal
cells expressing the triple mutant is 85% that of the wild-type BR
expressing cells. Therefore, the functional activity of BR seems to
be largely preserved in the triple mutant despite the observations
that its ground-state structure resembles that of the wild-type M
state (i.e., the so-called cytoplasmically open state) and that the
mutant shows no significant structural changes during its photocycle,
in sharp contrast to what occurs in the wild-type protein in which
a large structural opening and closing occurs on the cytoplasmic side.
To resolve the contradiction between the apparent functional robustness
of the triple mutant and the presumed importance of the opening and
closing that occurs in the wild-type protein, we conducted additional
experiments to compare the behavior of wild-type and mutant proteins
under different operational loads. Specifically, we characterized
the ability of the two proteins to generate light-driven proton currents
against a range of membrane potentials. The wild-type protein showed
maximal conductance between −150 and −50 mV, whereas
the mutant showed maximal conductance at membrane potentials >+50
mV. Molecular dynamics (MD) simulations of the triple mutant were
also conducted to characterize structural changes in the protein and
in solvent accessibility that might help to functionally contextualize
the current–voltage data. These simulations revealed that the
cytoplasmic half-channel of the triple mutant is constitutively open
and dynamically exchanges water with the bulk. Collectively, the data
and simulations help to explain why this mutant BR does not mediate
photosynthetic growth of haloarchaeal cells, and they suggest that
the structural closing observed in the wild-type protein likely plays
a key role in minimizing substrate back flow in the face of electrochemical
driving forces present at physiological membrane potentials.
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Affiliation(s)
- Ting Wang
- Department of Biomedical Engineering and Genome Center, 451 East Health Science Drive, University of California , Davis, California 95616-8816, United States
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