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Aoyama M, Katayama K, Kandori H. Unique hydrogen-bonding network in a viral channelrhodopsin. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149148. [PMID: 38906314 DOI: 10.1016/j.bbabio.2024.149148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/10/2024] [Accepted: 06/13/2024] [Indexed: 06/23/2024]
Abstract
Channelrhodopsins (CRs) are used as key tools in optogenetics, and novel CRs, either found from nature or engineered by mutation, have greatly contributed to the development of optogenetics. Recently CRs were discovered from viruses, and crystal structure of a viral CR, OLPVR1, reported a very similar water-containing hydrogen-bonding network near the retinal Schiff base to that of a light-driven proton-pump bacteriorhodopsin (BR). In both OLPVR1 and BR, nearly planar pentagonal cluster structures are comprised of five oxygen atoms, three oxygens from water molecules and two oxygens from the Schiff base counterions. The planar pentagonal cluster stabilizes a quadrupole, two positive charges at the Schiff base and an arginine, and two negative charges at the counterions, and thus plays important roles in light-gated channel function of OLPVR1 and light-driven proton pump function of BR. Despite similar pentagonal cluster structures, present FTIR analysis revealed different hydrogen-bonding networks between OLPVR1 and BR. The hydrogen bond between the protonated Schiff base and a water is stronger in OLPVR1 than in BR, and internal water molecules donate hydrogen bonds much weaker in OLPVR1 than in BR. In OLPVR1, the bridged water molecule between the Schiff base and counterions forms hydrogen bonds to D76 and D200 equally, while the hydrogen-bonding interaction is much stronger to D85 than to D212 in BR. The present interpretation is supported by the mutation results, where D76 and D200 equally work as the Schiff base counterions in OLPVR1, but D85 is the primary counterion in BR. This work reports highly sensitive hydrogen-bonding network in the Schiff base region, which would be closely related to each function through light-induced alterations of the network.
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Affiliation(s)
- Mako Aoyama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Kota Katayama
- 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 466-8555, 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 466-8555, Japan.
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2
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Lamm GHU, Zabelskii D, Balandin T, Gordeliy V, Wachtveitl J. Calcium-Sensitive Microbial Rhodopsin VirChR1: A Femtosecond to Second Photocycle Study. J Phys Chem Lett 2024; 15:5510-5516. [PMID: 38749015 DOI: 10.1021/acs.jpclett.4c00693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2024]
Abstract
Viral rhodopsins are light-gated cation channels representing a novel class of microbial rhodopsins. For viral rhodopsin 1 subfamily members VirChR1 and OLPVR1, channel activity is abolished above a certain calcium concentration. Here we present a calcium-dependent spectroscopic analysis of VirChR1 on the femtosecond to second time scale. Unlike channelrhodopsin-2, VirChR1 possesses two intermediate states P1 and P2 on the ultrafast time scale, similar to J and K in ion-pumping rhodopsins. Subsequently, we observe multifaceted photocycle kinetics with up to seven intermediate states. Calcium predominantly affects the last photocycle steps, including the appearance of additional intermediates P6Ca and P7 representing the blocked channel. Furthermore, the photocycle of the counterion variant D80N is drastically altered, yielding intermediates with different spectra and kinetics compared to those of the wt. These findings demonstrate the central role of the counterion within the defined reaction sequence of microbial rhodopsins that ultimately defines the protein function.
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Affiliation(s)
- Gerrit H U Lamm
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | | | - Taras Balandin
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, 52428 Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Valentin Gordeliy
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, 52428 Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52428 Jülich, Germany
- University Grenoble Alpes, CEA, CNRS, Institute de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Josef Wachtveitl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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3
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Fischer P, Schiewer E, Broser M, Busse W, Spreen A, Grosse M, Hegemann P, Bartl F. The Functionality of the DC Pair in a Rhodopsin Guanylyl Cyclase from Catenaria anguillulae. J Mol Biol 2024; 436:168375. [PMID: 38092286 DOI: 10.1016/j.jmb.2023.168375] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 12/29/2023]
Abstract
Rhodopsin guanylyl cyclases (RGCs) belong to the class of enzymerhodopsins catalyzing the transition from GTP into the second messenger cGMP, whereas light-regulation of enzyme activity is mediated by a membrane-bound microbial rhodopsin domain, that holds the catalytic center inactive in the dark. Structural determinants for activation of the rhodopsin moiety eventually leading to catalytic activity are largely unknown. Here, we investigate the mechanistic role of the D283-C259 (DC) pair that is hydrogen bonded via a water molecule as a crucial functional motif in the homodimeric C. anguillulae RGC. Based on a structural model of the DC pair in the retinal binding pocket obtained by MD simulation, we analyzed formation and kinetics of early and late photocycle intermediates of the rhodopsin domain wild type and specific DC pair mutants by combined UV-Vis and FTIR spectroscopy at ambient and cryo-temperatures. By assigning specific infrared bands to S-H vibrations of C259 we are able to show that the DC pair residues are tightly coupled. We show that deprotonation of D283 occurs already in the inactive L state as a prerequisite for M state formation, whereas structural changes of C259 occur in the active M state and early cryo-trapped intermediates. We propose a comprehensive molecular model for formation of the M state that activates the catalytic moiety. It involves light induced changes in bond strength and hydrogen bonding of the DC pair residues from the early J state to the active M state and explains the retarding effect of C259 mutants.
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Affiliation(s)
- Paul Fischer
- Institut für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstr, 42, 10115 Berlin, Germany.
| | - Enrico Schiewer
- Institut für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstr, 42, 10115 Berlin, Germany.
| | - Matthias Broser
- Institut für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstr, 42, 10115 Berlin, Germany.
| | - Wayne Busse
- Institut für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstr, 42, 10115 Berlin, Germany.
| | - Anika Spreen
- Institut für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstr, 42, 10115 Berlin, Germany.
| | - Max Grosse
- Institut für Biologie, Biophysikalische Chemie, Humboldt Universität zu Berlin, Invalidenstr, 42, 10115 Berlin, Germany.
| | - Peter Hegemann
- Institut für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstr, 42, 10115 Berlin, Germany.
| | - Franz Bartl
- Institut für Biologie, Biophysikalische Chemie, Humboldt Universität zu Berlin, Invalidenstr, 42, 10115 Berlin, Germany.
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4
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Sineshchekov OA, Govorunova EG, Li H, Wang Y, Spudich JL. Channel Gating in Kalium Channelrhodopsin Slow Mutants. J Mol Biol 2024; 436:168298. [PMID: 37802216 DOI: 10.1016/j.jmb.2023.168298] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/14/2023] [Accepted: 09/29/2023] [Indexed: 10/08/2023]
Abstract
Kalium channelrhodopsin 1 from Hyphochytrium catenoides (HcKCR1) is the first discovered natural light-gated ion channel that shows higher selectivity to K+ than to Na+ and therefore is used to silence neurons with light (optogenetics). Replacement of the conserved cysteine residue in the transmembrane helix 3 (Cys110) with alanine or threonine results in a >1,000-fold decrease in the channel closing rate. The phenotype of the corresponding mutants in channelrhodopsin 2 is attributed to breaking of a specific interhelical hydrogen bond (the "DC gate"). Unlike CrChR2 and other ChRs with long distance "DC gates", the HcKCR1 structure does not reveal any hydrogen bonding partners to Cys110, indicating that the mutant phenotype is likely caused by disruption of direct interaction between this residue and the chromophore. In HcKCR1_C110A, fast photochemical conversions corresponding to channel gating were followed by dramatically slower absorption changes. Full recovery of the unphotolyzed state in HcKCR1_C110A was extremely slow with two time constants 5.2 and 70 min. Analysis of the light-minus-dark difference spectra during these slow processes revealed accumulation of at least four spectrally distinct blue light-absorbing photocycle intermediates, L, M1 and M2, and a UV light-absorbing form, typical of bacteriorhodopsin-like channelrhodopsins from cryptophytes. Our results contribute to better understanding of the mechanistic links between the chromophore photochemistry and channel conductance, and provide the basis for using HcKCR1_C110A as an optogenetic tool.
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Affiliation(s)
- Oleg A Sineshchekov
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Elena G Govorunova
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Hai Li
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Yumei Wang
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - John L Spudich
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA.
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5
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Asido M, Boumrifak C, Weissbecker J, Bamberg E, Wachtveitl J. Vibrational Study of the Inward Proton Pump Xenorhodopsin NsXeR: Switch Order Determines Vectoriality. J Mol Biol 2024; 436:168447. [PMID: 38244766 DOI: 10.1016/j.jmb.2024.168447] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 01/12/2024] [Accepted: 01/12/2024] [Indexed: 01/22/2024]
Abstract
Common proton pumps, e.g. HsBR and PR, transport protons out of the cell. Xenorhodopsins (XeR) were the first discovered microbial rhodopsins which come as natural inward proton pumps. In this work we combine steady-state (cryo-)FTIR and Raman spectroscopy with time-resolved IR and UV/Vis measurements to roadmap the inward proton transport of NsXeR and pinpoint the most important mechanistic features. Through the assignment of characteristic bands of the protein backbone, the retinal chromophore, the retinal Schiff base and D220, we could follow the switching processes for proton accessibility in accordance with the isomerization / switch / transfer model. The corresponding transient IR signatures suggest that the initial assignment of D220 as the proton acceptor needs to be questioned due to the temporal mismatch of the Schiff base and D220 protonation steps. The switching events in the K-L and MCP-MEC transitions are finely tuned by changes of the protein backbone and rearrangements of the Schiff base. This finely tuned mechanism is disrupted at cryogenic temperatures, being reflected in the replacement of the previously reported long-lived intermediate GS* by an actual redshifted (O-like) intermediate.
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Affiliation(s)
- Marvin Asido
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue Straße 7, 60438 Frankfurt am Main, Germany
| | - Chokri Boumrifak
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue Straße 7, 60438 Frankfurt am Main, Germany
| | - Juliane Weissbecker
- Department of Biophysical Chemistry, Max-Planck-Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Ernst Bamberg
- Department of Biophysical Chemistry, Max-Planck-Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue Straße 7, 60438 Frankfurt am Main, Germany.
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6
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Urui T, Hayashi K, Mizuno M, Inoue K, Kandori H, Mizutani Y. Cis- Trans Reisomerization Preceding Reprotonation of the Retinal Chromophore Is Common to the Schizorhodopsin Family: A Simple and Rational Mechanism for Inward Proton Pumping. J Phys Chem B 2024; 128:744-754. [PMID: 38204413 DOI: 10.1021/acs.jpcb.3c07510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The creation of unidirectional ion transporters across membranes represents one of the greatest challenges in chemistry. Proton-pumping rhodopsins are composed of seven transmembrane helices with a retinal chromophore bound to a lysine side chain via a Schiff base linkage and provide valuable insights for designing such transporters. What makes these transporters particularly intriguing is the discovery of both outward and inward proton-pumping rhodopsins. Surprisingly, despite sharing identical overall structures and membrane topologies, these proteins facilitate proton transport in opposite directions, implying an underlying rational mechanism that can transport protons in different directions within similar protein structures. In this study, we unraveled this mechanism by examining the chromophore structures of deprotonated intermediates in schizorhodopsins, a recently discovered subfamily of inward proton-pumping rhodopsins, using time-resolved resonance Raman spectroscopy. The photocycle of schizorhodopsins revealed the cis-trans thermal isomerization that precedes reprotonation at the Schiff base of the retinal chromophore. Notably, this order has not been observed in other proton-pumping rhodopsins, but here, it was observed in all seven schizorhodopsins studied across the archaeal domain, strongly suggesting that cis-trans thermal isomerization preceding reprotonation is a universal feature of the schizorhodopsin family. Based on these findings, we propose a structural basis for the remarkable order of events crucial for facilitating inward proton transport. The mechanism underlying inward proton transport by schizorhodopsins is straightforward and rational. The insights obtained from this study hold great promise for the design of transmembrane unidirectional ion transporters.
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Affiliation(s)
- Taito Urui
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Kouhei Hayashi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Misao Mizuno
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Yasuhisa Mizutani
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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7
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Bühl E, Resler T, Lam R, Asido M, Bamberg E, Schlesinger R, Bamann C, Heberle J, Wachtveitl J. Assessing the Role of R120 in the Gating of CrChR2 by Time-Resolved Spectroscopy from Femtoseconds to Seconds. J Am Chem Soc 2023; 145:21832-21840. [PMID: 37773976 DOI: 10.1021/jacs.3c05399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2023]
Abstract
The light-gated ion channel channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2) is the most frequently used optogenetic tool in neurosciences. However, the precise molecular mechanism of the channel opening and the correlation among retinal isomerization, the photocycle, and the channel activity of the protein are missing. Here, we present electrophysiological and spectroscopic investigations on the R120H variant of CrChR2. R120 is a key residue in an extended network linking the retinal chromophore to several gates of the ion channel. We show that despite the deficient channel activity, the photocycle of the variant is intact. In a comparative study for R120H and the wild type, we resolve the vibrational changes in the spectral range of the retinal and amide I bands across the time range from femtoseconds to seconds. Analysis of the amide I mode reveals a significant impairment of the ultrafast protein response after retinal excitation. We conclude that channel opening in CrChR2 is prepared immediately after retinal excitation. Additionally, chromophore isomerization is essential for both photocycle and channel activities, although both processes can occur independently.
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Affiliation(s)
- Elena Bühl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt am Main, Max-von-Laue Strasse 7, 60438 Frankfurt, Germany
| | - Tom Resler
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Rebecca Lam
- Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany
| | - Marvin Asido
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt am Main, Max-von-Laue Strasse 7, 60438 Frankfurt, Germany
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany
| | - Ramona Schlesinger
- Department of Physics, Genetic Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Christian Bamann
- Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany
| | - Joachim Heberle
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt am Main, Max-von-Laue Strasse 7, 60438 Frankfurt, Germany
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8
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Gulzar A, Noetzel J, Forbert H, Marx D. Elucidating the Self-cleavage Dynamics of Hairpin Ribozyme by Mode-decomposed Infrared Spectroscopy. J Phys Chem Lett 2023; 14:7940-7945. [PMID: 37646493 DOI: 10.1021/acs.jpclett.3c01724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
While catalytic reactions of biomolecular processes play an indispensable role in life, extracting the underlying molecular picture often remains challenging. Based on ab initio simulations of the self-cleavage reaction of hairpin ribozyme, mode-decomposed infrared spectra, and cosine similarity analysis to correlate the product with reactant IR spectra, we demonstrate a strategy to extract molecular details from characteristic spectral changes. Our results are in almost quantitative agreement with the experimental IR band library of nucleic acids and suggest that the spectral range of 800-1200 cm-1 is particularly valuable to monitor self-cleavage. Importantly, the cosine similarities also disclose that IR peaks subject to slight shifts due to self-cleavage might be unrelated, while strongly shifting resonances can correspond to the same structural dynamics. This framework of correlating complex IR spectra at the molecular level along biocatalytic reaction pathways is broadly applicable.
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Affiliation(s)
- Adnan Gulzar
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Jan Noetzel
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Harald Forbert
- Center for Solvation Science ZEMOS, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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9
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Shibata K, Oda K, Nishizawa T, Hazama Y, Ono R, Takaramoto S, Bagherzadeh R, Yawo H, Nureki O, Inoue K, Akiyama H. Twisting and Protonation of Retinal Chromophore Regulate Channel Gating of Channelrhodopsin C1C2. J Am Chem Soc 2023; 145:10779-10789. [PMID: 37129501 DOI: 10.1021/jacs.3c01879] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Channelrhodopsins (ChRs) are light-gated ion channels and central optogenetic tools that can control neuronal activity with high temporal resolution at the single-cell level. Although their application in optogenetics has rapidly progressed, it is unsolved how their channels open and close. ChRs transport ions through a series of interlocking elementary processes that occur over a broad time scale of subpicoseconds to seconds. During these processes, the retinal chromophore functions as a channel regulatory domain and transfers the optical input as local structural changes to the channel operating domain, the helices, leading to channel gating. Thus, the core question on channel gating dynamics is how the retinal chromophore structure changes throughout the photocycle and what rate-limits the kinetics. Here, we investigated the structural changes in the retinal chromophore of canonical ChR, C1C2, in all photointermediates using time-resolved resonance Raman spectroscopy. Moreover, to reveal the rate-limiting factors of the photocycle and channel gating, we measured the kinetic isotope effect of all photoreaction processes using laser flash photolysis and laser patch clamp, respectively. Spectroscopic and electrophysiological results provided the following understanding of the channel gating: the retinal chromophore highly twists upon the retinal Schiff base (RSB) deprotonation, causing the surrounding helices to move and open the channel. The ion-conducting pathway includes the RSB, where inflowing water mediates the proton to the deprotonated RSB. The twisting of the retinal chromophore relaxes upon the RSB reprotonation, which closes the channel. The RSB reprotonation rate-limits the channel closing.
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Affiliation(s)
- Keisei Shibata
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Kazumasa Oda
- Department of Biological Sciences Graduate School of Science, The University of Tokyo, Tokyo 113-0034, Japan
| | - Tomohiro Nishizawa
- Department of Biological Sciences Graduate School of Science, The University of Tokyo, Tokyo 113-0034, Japan
| | - Yuji Hazama
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Ryohei Ono
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Shunki Takaramoto
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Reza Bagherzadeh
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Hiromu Yawo
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Osamu Nureki
- Department of Biological Sciences Graduate School of Science, The University of Tokyo, Tokyo 113-0034, Japan
| | - Keiichi Inoue
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Hidefumi Akiyama
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
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10
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Govorunova EG, Sineshchekov OA, Spudich JL. Potassium-selective channelrhodopsins. Biophys Physicobiol 2023; 20:e201011. [PMID: 38362336 PMCID: PMC10865875 DOI: 10.2142/biophysico.bppb-v20.s011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 02/03/2023] [Indexed: 02/05/2023] Open
Abstract
Since their discovery 21 years ago, channelrhodopsins have come of age and have become indispensable tools for optogenetic control of excitable cells such as neurons and myocytes. Potential therapeutic utility of channelrhodopsins has been proven by partial vision restoration in a human patient. Previously known channelrhodopsins are either proton channels, non-selective cation channels almost equally permeable to Na+ and K+ besides protons, or anion channels. Two years ago, we discovered a group of channelrhodopsins that exhibit over an order of magnitude higher selectivity for K+ than for Na+. These proteins, known as "kalium channelrhodopsins" or KCRs, lack the canonical tetrameric selectivity filter found in voltage- and ligand-gated K+ channels, and use a unique selectivity mechanism intrinsic to their individual protomers. Mutant analysis has revealed that the key residues responsible for K+ selectivity in KCRs are located at both ends of the putative cation conduction pathway, and their role has been confirmed by high-resolution KCR structures. Expression of KCRs in mouse neurons and human cardiomyocytes enabled optical inhibition of these cells' electrical activity. In this minireview we briefly discuss major results of KCR research obtained during the last two years and suggest some directions of future research.
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Affiliation(s)
- Elena G. Govorunova
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, USA
| | - Oleg A. Sineshchekov
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, USA
| | - John L. Spudich
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, USA
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11
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Sushmita K, Sharma S, Singh Kaushik M, Kateriya S. Algal rhodopsins encoding diverse signal sequence holds potential for expansion of organelle optogenetics. Biophys Physicobiol 2023; 20:e201008. [PMID: 38362319 PMCID: PMC10865886 DOI: 10.2142/biophysico.bppb-v20.s008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
Rhodopsins have been extensively employed for optogenetic regulation of bioelectrical activity of excitable cells and other cellular processes across biological systems. Various strategies have been adopted to attune the cellular processes at the desired subcellular compartment (plasma membrane, endoplasmic reticulum, Golgi, mitochondria, lysosome) within the cell. These strategies include-adding signal sequences, tethering peptides, specific interaction sites, or mRNA elements at different sites in the optogenetic proteins for plasma membrane integration and subcellular targeting. However, a single approach for organelle optogenetics was not suitable for the relevant optogenetic proteins and often led to the poor expression, mislocalization, or altered physical and functional properties. Therefore, the current study is focused on the native subcellular targeting machinery of algal rhodopsins. The N- and C-terminus signal prediction led to the identification of rhodopsins with diverse organelle targeting signal sequences for the nucleus, mitochondria, lysosome, endosome, vacuole, and cilia. Several identified channelrhodopsins and ion-pumping rhodopsins possess effector domains associated with DNA metabolism (repair, replication, and recombination) and gene regulation. The identified algal rhodopsins with diverse effector domains and encoded native subcellular targeting sequences hold immense potential to establish expanded organelle optogenetic regulation and associated cellular signaling.
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Affiliation(s)
- Kumari Sushmita
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Sunita Sharma
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Manish Singh Kaushik
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Suneel Kateriya
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
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12
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Heckmeier PJ, Ruf J, Janković BG, Hamm P. MCL-1 promiscuity and the structural resilience of its binding partners. J Chem Phys 2023; 158:095101. [PMID: 36889945 DOI: 10.1063/5.0137239] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
The allosteric protein MCL-1 and its natural inhibitors, the BH3-only proteins PUMA, BIM, and NOXA regulate apoptosis by interacting promiscuously within an entangled binding network. Little is known about the transient processes and dynamic conformational fluctuations that are the basis for the formation and stability of the MCL-1/BH3-only complex. In this study, we designed photoswitchable versions of MCL-1/PUMA and MCL-1/NOXA, and investigated the protein response after an ultrafast photo-perturbation with transient infrared spectroscopy. We observed partial α-helical unfolding in all cases, albeit on strongly varying timescales (1.6 ns for PUMA, 9.7 ns for the previously studied BIM, and 85 ns for NOXA). These differences are interpreted as a BH3-only-specific "structural resilience" to defy the perturbation while remaining in MCL-1's binding pocket. Thus, the presented insights could help to better understand the differences between PUMA, BIM, and NOXA, the promiscuity of MCL-1, in general, and the role of the proteins in the apoptotic network.
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Affiliation(s)
| | - Jeannette Ruf
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | | | - Peter Hamm
- Department of Chemistry, University of Zurich, Zurich, Switzerland
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13
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Tucker K, Sridharan S, Adesnik H, Brohawn SG. Cryo-EM structures of the channelrhodopsin ChRmine in lipid nanodiscs. Nat Commun 2022; 13:4842. [PMID: 35977941 PMCID: PMC9385719 DOI: 10.1038/s41467-022-32441-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 08/01/2022] [Indexed: 12/03/2022] Open
Abstract
Microbial channelrhodopsins are light-gated ion channels widely used for optogenetic manipulation of neuronal activity. ChRmine is a bacteriorhodopsin-like cation channelrhodopsin (BCCR) more closely related to ion pump rhodopsins than other channelrhodopsins. ChRmine displays unique properties favorable for optogenetics including high light sensitivity, a broad, red-shifted activation spectrum, cation selectivity, and large photocurrents, while its slow closing kinetics impedes some applications. The structural basis for ChRmine function, or that of any other BCCR, is unknown. Here, we present cryo-EM structures of ChRmine in lipid nanodiscs in apo (opsin) and retinal-bound (rhodopsin) forms. The structures reveal an unprecedented trimeric architecture with a lipid filled central pore. Large electronegative cavities on either side of the membrane facilitate high conductance and selectivity for cations over protons. The retinal binding pocket structure suggests channel properties could be tuned with mutations and we identify ChRmine variants with ten-fold decreased and two-fold increased closing rates. A T119A mutant shows favorable properties relative to wild-type and previously reported ChRmine variants for optogenetics. These results provide insight into structural features that generate an ultra-potent microbial opsin and provide a platform for rational engineering of channelrhodopsins with improved properties that could expand the scale, depth, and precision of optogenetic experiments.
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Affiliation(s)
- Kyle Tucker
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, 94720, USA
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA
- California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, 94720, USA
| | - Savitha Sridharan
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, 94720, USA
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Hillel Adesnik
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, 94720, USA.
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA.
| | - Stephen G Brohawn
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, 94720, USA.
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA.
- California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, 94720, USA.
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14
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Lazaratos M, Siemers M, Brown LS, Bondar AN. Conserved hydrogen-bond motifs of membrane transporters and receptors. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183896. [PMID: 35217000 DOI: 10.1016/j.bbamem.2022.183896] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/04/2022] [Accepted: 02/16/2022] [Indexed: 01/18/2023]
Abstract
Membrane transporters and receptors often rely on conserved hydrogen bonds to assemble transient paths for ion transfer or long-distance conformational couplings. For transporters and receptors that use proton binding and proton transfer for function, inter-helical hydrogen bonds of titratable protein sidechains that could change protonation are of central interest to formulate hypotheses about reaction mechanisms. Knowledge of hydrogen bonds common at sites of potential interest for proton binding could thus inform and guide studies on functional mechanisms of protonation-coupled membrane proteins. Here we apply graph-theory approaches to identify hydrogen-bond motifs of carboxylate and histidine sidechains in a large data set of static membrane protein structures. We find that carboxylate-hydroxyl hydrogen bonds are present in numerous structures of the dataset, and can be part of more extended H-bond clusters that could be relevant to conformational coupling. Carboxylate-carboxyamide and imidazole-imidazole hydrogen bonds are represented in comparably fewer protein structures of the dataset. Atomistic simulations on two membrane transporters in lipid membranes suggest that many of the hydrogen bond motifs present in static protein structures tend to be robust, and can be part of larger hydrogen-bond clusters that recruit additional hydrogen bonds.
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Affiliation(s)
- Michalis Lazaratos
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany
| | - Malte Siemers
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany
| | - Leonid S Brown
- University of Guelph, Department of Physics, 50 Stone Road E., Guelph, Ontario N1G 2W1, Canada
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany; University of Bucharest, Faculty of Physics, Atomiștilor 405, Măgurele 077125, Romania; Forschungszentrum Jülich, Institute for Neuroscience and Medicine and Institute for Advanced Simulations (IAS-5/INM-9), Computational Biomedicine, Wilhelm-Johnen Straße, 52428 Jülich, Germany.
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15
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Brown LS. Light-driven proton transfers and proton transport by microbial rhodopsins - A biophysical perspective. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183867. [PMID: 35051382 DOI: 10.1016/j.bbamem.2022.183867] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/30/2021] [Accepted: 01/10/2022] [Indexed: 12/31/2022]
Abstract
In the last twenty years, our understanding of the rules and mechanisms for the outward light-driven proton transport (and underlying proton transfers) by microbial rhodopsins has been changing dramatically. It transitioned from a very detailed atomic-level understanding of proton transport by bacteriorhodopsin, the prototypical proton pump, to a confounding variety of sequence motifs, mechanisms, directions, and modes of transport in its newly found homologs. In this review, we will summarize and discuss experimental data obtained on new microbial rhodopsin variants, highlighting their contribution to the refinement and generalization of the ideas crystallized in the previous century. In particular, we will focus on the proton transport (and transfers) vectoriality and their structural determinants, which, in many cases, remain unidentified.
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Affiliation(s)
- Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Ontario N1G 2W1, Canada.
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16
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Zhang L, Wang K, Ning S, Pedersen PA, Duelli AS, Gourdon PE. Isolation and Crystallization of the D156C form of Optogenetic ChR2. Cells 2022; 11:cells11050895. [PMID: 35269517 PMCID: PMC8909857 DOI: 10.3390/cells11050895] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/02/2022] [Accepted: 03/03/2022] [Indexed: 02/07/2023] Open
Abstract
Channelrhodopsins (ChRs) are light-gated ion channels that are receiving increasing attention as optogenetic tools. Despite extensive efforts to gain understanding of how these channels function, the molecular events linking light absorption of the retinal cofactor to channel opening remain elusive. While dark-state structures of ChR2 or chimeric proteins have demonstrated the architecture of non-conducting states, there is a need for open- and desensitized-state structures to uncover the mechanistic principles underlying channel activity. To facilitate comprehensive structural studies of ChR2 in non-closed states, we report a production and purification procedure of the D156C form of ChR2, which displays prolonged channel opening compared to the wild type. We demonstrate considerable yields (0.45 mg/g fermenter cell culture) of recombinantly produced protein using S. cerevisiae, which is purified to high homogeneity both as opsin (retinal-free) and as functional ChR2 with added retinal. We also develop conditions that enable the growth of ChR2 crystals that scatter X-rays to 6 Å, and identify a molecular replacement solution that suggests that the packing is different from published structures. Consequently, our cost-effective production and purification pipeline opens the way for downstream structural studies of different ChR2 states, which may provide a foundation for further adaptation of this protein for optogenetic applications.
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Affiliation(s)
- Liying Zhang
- Department of Biomedical Sciences, University of Copenhagen, Nørre Allé 14, DK-2200 Copenhagen, Denmark; (L.Z.); (K.W.); (A.S.D.)
| | - Kaituo Wang
- Department of Biomedical Sciences, University of Copenhagen, Nørre Allé 14, DK-2200 Copenhagen, Denmark; (L.Z.); (K.W.); (A.S.D.)
| | - Shuo Ning
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China;
| | - Per Amstrup Pedersen
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen, Denmark;
| | - Annette Susanne Duelli
- Department of Biomedical Sciences, University of Copenhagen, Nørre Allé 14, DK-2200 Copenhagen, Denmark; (L.Z.); (K.W.); (A.S.D.)
| | - Pontus Emanuel Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Nørre Allé 14, DK-2200 Copenhagen, Denmark; (L.Z.); (K.W.); (A.S.D.)
- Department of Experimental Medical Science, Lund University, Sölvegatan 19, SE-221 84 Lund, Sweden
- Correspondence: ; Tel.: +45-50339990
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17
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Mous S, Gotthard G, Ehrenberg D, Sen S, Weinert T, Johnson PJM, James D, Nass K, Furrer A, Kekilli D, Ma P, Brünle S, Casadei CM, Martiel I, Dworkowski F, Gashi D, Skopintsev P, Wranik M, Knopp G, Panepucci E, Panneels V, Cirelli C, Ozerov D, Schertler GFX, Wang M, Milne C, Standfuss J, Schapiro I, Heberle J, Nogly P. Dynamics and mechanism of a light-driven chloride pump. Science 2022; 375:845-851. [PMID: 35113649 DOI: 10.1126/science.abj6663] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Chloride transport by microbial rhodopsins is an essential process for which molecular details such as the mechanisms that convert light energy to drive ion pumping and ensure the unidirectionality of the transport have remained elusive. We combined time-resolved serial crystallography with time-resolved spectroscopy and multiscale simulations to elucidate the molecular mechanism of a chloride-pumping rhodopsin and the structural dynamics throughout the transport cycle. We traced transient anion-binding sites, obtained evidence for how light energy is used in the pumping mechanism, and identified steric and electrostatic molecular gates ensuring unidirectional transport. An interaction with the π-electron system of the retinal supports transient chloride ion binding across a major bottleneck in the transport pathway. These results allow us to propose key mechanistic features enabling finely controlled chloride transport across the cell membrane in this light-powered chloride ion pump.
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Affiliation(s)
- Sandra Mous
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Guillaume Gotthard
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, Zürich, Switzerland.,Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - David Ehrenberg
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Berlin, Germany
| | - Saumik Sen
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tobias Weinert
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Philip J M Johnson
- Laboratory of Nonlinear Optics, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Daniel James
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Karol Nass
- Laboratory of Femtochemistry, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Antonia Furrer
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Demet Kekilli
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Pikyee Ma
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Steffen Brünle
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Cecilia Maria Casadei
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, Zürich, Switzerland.,Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Isabelle Martiel
- Laboratory for Macromolecules and Bioimaging, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Florian Dworkowski
- Laboratory for Macromolecules and Bioimaging, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Dardan Gashi
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland.,Laboratory of Femtochemistry, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Petr Skopintsev
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Maximilian Wranik
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Gregor Knopp
- Laboratory of Femtochemistry, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Ezequiel Panepucci
- Laboratory for Macromolecules and Bioimaging, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Valerie Panneels
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Claudio Cirelli
- Laboratory of Femtochemistry, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Dmitry Ozerov
- Science IT, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Gebhard F X Schertler
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, Zürich, Switzerland.,Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Meitian Wang
- Laboratory for Macromolecules and Bioimaging, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Chris Milne
- Laboratory of Femtochemistry, Photon Science Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Joerg Standfuss
- Laboratory of Biomolecular Research, Biology and Chemistry Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Joachim Heberle
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Berlin, Germany
| | - Przemyslaw Nogly
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, Zürich, Switzerland
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18
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Kishi KE, Kim YS, Fukuda M, Inoue M, Kusakizako T, Wang PY, Ramakrishnan C, Byrne EFX, Thadhani E, Paggi JM, Matsui TE, Yamashita K, Nagata T, Konno M, Quirin S, Lo M, Benster T, Uemura T, Liu K, Shibata M, Nomura N, Iwata S, Nureki O, Dror RO, Inoue K, Deisseroth K, Kato HE. Structural basis for channel conduction in the pump-like channelrhodopsin ChRmine. Cell 2022; 185:672-689.e23. [PMID: 35114111 PMCID: PMC7612760 DOI: 10.1016/j.cell.2022.01.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/13/2021] [Accepted: 01/11/2022] [Indexed: 12/24/2022]
Abstract
ChRmine, a recently discovered pump-like cation-conducting channelrhodopsin, exhibits puzzling properties (large photocurrents, red-shifted spectrum, and extreme light sensitivity) that have created new opportunities in optogenetics. ChRmine and its homologs function as ion channels but, by primary sequence, more closely resemble ion pump rhodopsins; mechanisms for passive channel conduction in this family have remained mysterious. Here, we present the 2.0 Å resolution cryo-EM structure of ChRmine, revealing architectural features atypical for channelrhodopsins: trimeric assembly, a short transmembrane-helix 3, a twisting extracellular-loop 1, large vestibules within the monomer, and an opening at the trimer interface. We applied this structure to design three proteins (rsChRmine and hsChRmine, conferring further red-shifted and high-speed properties, respectively, and frChRmine, combining faster and more red-shifted performance) suitable for fundamental neuroscience opportunities. These results illuminate the conduction and gating of pump-like channelrhodopsins and point the way toward further structure-guided creation of channelrhodopsins for applications across biology.
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Affiliation(s)
- Koichiro E Kishi
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Yoon Seok Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Masahiro Fukuda
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Masatoshi Inoue
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Peter Y Wang
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | | | - Eamon F X Byrne
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Elina Thadhani
- Department of Bioengineering, Stanford University, Stanford, CA, USA; Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Joseph M Paggi
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Toshiki E Matsui
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Keitaro Yamashita
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Takashi Nagata
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Masae Konno
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Sean Quirin
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Maisie Lo
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Tyler Benster
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Tomoko Uemura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan
| | - Kehong Liu
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan
| | - Mikihiro Shibata
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma, Kanazawa, Japan; High-Speed AFM for Biological Application Unit, Institute for Frontier Science Initiative, Kanazawa University, Kakuma, Kanazawa, Japan
| | - Norimichi Nomura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan
| | - So Iwata
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan; RIKEN SPring-8 Center, Kouto, Sayo-cho, Sayo-gun, Hyogo, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Ron O Dror
- Department of Computer Science, Stanford University, Stanford, CA, USA; Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Keiichi Inoue
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, USA; CNC Program, Stanford University, Palo Alto, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA; Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA.
| | - Hideaki E Kato
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan; FOREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan.
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19
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Heckmeier PJ, Ruf J, Buhrke D, Janković BG, Hamm P. Signal propagation within the MCL-1/BIM protein complex. J Mol Biol 2022; 434:167499. [DOI: 10.1016/j.jmb.2022.167499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/24/2022] [Accepted: 02/07/2022] [Indexed: 11/26/2022]
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20
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Bondar AN. Mechanisms of long-distance allosteric couplings in proton-binding membrane transporters. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2022; 128:199-239. [PMID: 35034719 DOI: 10.1016/bs.apcsb.2021.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Membrane transporters that use proton binding and proton transfer for function couple local protonation change with changes in protein conformation and water dynamics. Changes of protein conformation might be required to allow transient formation of hydrogen-bond networks that bridge proton donor and acceptor pairs separated by long distances. Inter-helical hydrogen-bond networks adjust rapidly to protonation change, and ensure rapid response of the protein structure and dynamics. Membrane transporters with known three-dimensional structures and proton-binding groups inform on general principles of protonation-coupled protein conformational dynamics. Inter-helical hydrogen bond motifs between proton-binding carboxylate groups and a polar sidechain are observed in unrelated membrane transporters, suggesting common principles of coupling protonation change with protein conformational dynamics.
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Affiliation(s)
- Ana-Nicoleta Bondar
- University of Bucharest, Faculty of Physics, Măgurele, Romania; Forschungszentrum Jülich, Institute of Computational Biomedicine, Jülich, Germany.
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21
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Xin Q, Cheng J, Wang H, Zhang W, Lu H, Zhou J, Lo GV, Dou Y, Yuan S. Modeling the syn-cycle in the light activated opening of the channelrhodopsin-2 ion channel. RSC Adv 2022; 12:6515-6524. [PMID: 35424642 PMCID: PMC8981705 DOI: 10.1039/d1ra08521b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 02/14/2022] [Indexed: 11/21/2022] Open
Abstract
The ion channel of channelrhodopsin-2 (ChR2) is activated by absorbing light. The light stimulates retinal to isomerize to start the photocycle. There are two pathways for photocycles, which are caused by isomerization of the retinal from all-trans, 15-anti to 13-cis, 15-anti in the dark-adapted state (anti-cycle) and from 13-cis, 15-syn to all-trans, 15-syn in the light-adapted state (syn-cycle). In this work, the structure of the syn-cycle intermediate and mechanism of channel opening were studied by molecular dynamics (MD) and steered molecular dynamics (SMD) simulations. Due to the lack of crystal structure of intermediates in the syn-cycle of ChR2, the intermediate models were constructed from the homologous intermediates in the anti-cycle. The isomerization of retinal was shown to cause the central gate (CG) hydrogen bond network to rearrange, cutting the link between TM2 and TM7. TM2 is moved by the intrahelical hydrogen bond of E90 and K93, and induced the intracellular gate (ICG) to expand. The ion penetration pathway between TM1, TM2, TM3 and TM7 in the P500* state was observed by MD simulations. However, this channel is not fully opened compared with the homologous P500 state in the anti-cycle. In addition, the protons on Schiff bases were found to be unable to form hydrogen bonds with the counter residues (E123 and D253) in the P500* state, preventing an evolution of the P500* state to a P390-like state in the syn-cycle. Modelling the syn-cycle is a series of operations on the ChR2 crystal structure (PDB ID: 6EID). By replacement and isomerization, we obtained P500* and P480 intermediates. A feasible explanation that no P390* was observed in experiment was inferred.![]()
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Affiliation(s)
- Qi Xin
- Chongqing Key Laboratory of Big Data for Bio Intelligence, Chongqing University of Posts and Telecommunications, Chongqing 40065, China
| | - Jie Cheng
- Chongqing Key Laboratory of Big Data for Bio Intelligence, Chongqing University of Posts and Telecommunications, Chongqing 40065, China
| | - Hongwei Wang
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane St Lucia, QLD 4072, Australia
| | - Wenying Zhang
- Chongqing Key Laboratory of Big Data for Bio Intelligence, Chongqing University of Posts and Telecommunications, Chongqing 40065, China
| | - Hong Lu
- Chongqing Key Laboratory of Big Data for Bio Intelligence, Chongqing University of Posts and Telecommunications, Chongqing 40065, China
| | - Junpeng Zhou
- Chongqing Key Laboratory of Big Data for Bio Intelligence, Chongqing University of Posts and Telecommunications, Chongqing 40065, China
| | - Glenn V. Lo
- Department of Chemistry and Physical Sciences, Nicholls State University, P.O. Box 2022, Thibodaux, LA 70310, USA
| | - Yusheng Dou
- Department of Chemistry and Physical Sciences, Nicholls State University, P.O. Box 2022, Thibodaux, LA 70310, USA
| | - Shuai Yuan
- Chongqing Key Laboratory of Big Data for Bio Intelligence, Chongqing University of Posts and Telecommunications, Chongqing 40065, China
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22
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Abstract
Optogenetics has revolutionized not only neuroscience but also had an impact on muscle physiology and cell biology. Rhodopsin-based optogenetics started with the discovery of the light-gated cation channels, called channelrhodopsins. Together with the light-driven ion pumps, these channels allow light-mediated control of electrically excitable cells in culture tissue and living animals. They can be activated (depolarized) or silenced (hyperpolarized) by light with incomparably high spatiotemporal resolution. Optogenetics allows the light manipulation of cells under electrode-free conditions in a minimally invasive manner. Through modern genetic techniques, virus-induced transduction can be performed with extremely high cell specificity in tissue and living animals, allowing completely new approaches for analyzing neural networks, behavior studies, and investigations of neurodegenerative diseases. First clinical trials for the optogenetic recovery of vision are underway.This chapter provides a comprehensive description of the structure and function of the different light-gated channels and some new light-activated ion pumps. Some of them already play an essential role in optogenetics while others are supposed to become important tools for more specialized applications in the future.At the moment, a large number of publications are available concerning intrinsic mechanisms of microbial rhodopsins. Mostly they describe CrChR2 and its variants, as CrChR2 is still the most prominent optogenetic tool. Therefore, many biophysically and biochemically oriented groups contributed to the overwhelming mass of information on this unique ion channel's molecular mechanism. In this context, the function of new optogenetic tools is discussed, which is essential for rational optimization of the optogenetic approach for an eventual biomedical application. The comparison of the effectivity of ion pumps versus ion channels is discussed as well.Applications of rhodopsins-based optogenetic tools are also discussed in the chapter. Because of the enormous number of these applications in neuroscience, only exemplary studies on cell culture neural tissue, muscle physiology, and remote control of animal behavior are presented.
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Affiliation(s)
- Alexey Alekseev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Valentin Gordeliy
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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23
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Abstract
Cation and anion channelrhodopsins (CCRs and ACRs, respectively) primarily from two algal species, Chlamydomonas reinhardtii and Guillardia theta, have become widely used as optogenetic tools to control cell membrane potential with light. We mined algal and other protist polynucleotide sequencing projects and metagenomic samples to identify 75 channelrhodopsin homologs from four channelrhodopsin families, including one revealed in dinoflagellates in this study. We carried out electrophysiological analysis of 33 natural channelrhodopsin variants from different phylogenetic lineages and 10 metagenomic homologs in search of sequence determinants of ion selectivity, photocurrent desensitization, and spectral tuning in channelrhodopsins. Our results show that association of a reduced number of glutamates near the conductance path with anion selectivity depends on a wider protein context, because prasinophyte homologs with a glutamate pattern identical to that in cryptophyte ACRs are cation selective. Desensitization is also broadly context dependent, as in one branch of stramenopile ACRs and their metagenomic homologs, its extent roughly correlates with phylogenetic relationship of their sequences. Regarding spectral tuning, we identified two prasinophyte CCRs with red-shifted spectra to 585 nm. They exhibit a third residue pattern in their retinal-binding pockets distinctly different from those of the only two types of red-shifted channelrhodopsins known (i.e., the CCR Chrimson and RubyACRs). In cryptophyte ACRs we identified three specific residue positions in the retinal-binding pocket that define the wavelength of their spectral maxima. Lastly, we found that dinoflagellate rhodopsins with a TCP motif in the third transmembrane helix and a metagenomic homolog exhibit channel activity.
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24
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Govindan R, Banerjee P, Dhania NK, Senapati S. FTIR based approach to study EnaC mechanosensory functions. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 167:79-86. [PMID: 34293339 DOI: 10.1016/j.pbiomolbio.2021.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 07/07/2021] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
The pulmonary epithelial sodium ion channel (ENaC) is gaining importance for its sodium gating and mechanosensitive roles. The mechano functional studies on ENaC suggest direct molecular interactions between the ENaC protein with cytoskeleton microtubules and other extracellular matrix components. Also, in few mechanotransduction studies, ENaC was shown to respond both to membrane stretch as well as cell volume changes. However, the conformational characteristic of ENaC during sodium and mechano gating are yet to be fully elucidated. Thus obtaining ENaC protein conformational spectrum based on Fourier Transform Infrared Radiation (FTIR) spectroscopy in solution will be useful in predicting the nature of conformational changes occurring during any cell volume changes in an epithelial cell. The conformational spectrum looks promising in studying the disease biology of cystic fibrosis (CF) and CF like conditions that arise due to abnormal ion conductance membrane proteins and subsequent frequent fluid retentions. This review article presents the basics of epithelial ENaC protein as a gated mechanosensor and FTIR for developing fluid dynamics of ENaC protein. This can be applied to develop an ENaC based quantum mechanosensor for the prognosis as well as diagnosis of cystic fibrosis (CF) and allied lung diseases.
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Affiliation(s)
- Rekha Govindan
- Department of Biochemistry, PM Sayeed Calicut University Centre, Andrott, Lakshadweep, 682551, India
| | - Pratibha Banerjee
- Department of Human Genetics & Molecular Medicine, Central University of Punjab, Bathinda, 151401, India
| | - Narender K Dhania
- Department of Human Genetics & Molecular Medicine, Central University of Punjab, Bathinda, 151401, India.
| | - Sabyasachi Senapati
- Department of Human Genetics & Molecular Medicine, Central University of Punjab, Bathinda, 151401, India
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25
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Adam S, Wiebeler C, Schapiro I. Structural Factors Determining the Absorption Spectrum of Channelrhodopsins: A Case Study of the Chimera C1C2. J Chem Theory Comput 2021; 17:6302-6313. [PMID: 34255519 DOI: 10.1021/acs.jctc.1c00160] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Channelrhodopsins are photosensitive proteins that trigger flagella motion in single-cell algae and have been successfully utilized in optogenetic applications. In optogenetics, light is used to activate neural cells in living organisms, which can be achieved by exploiting the ion channel signaling of channelrhodopsins. Tailoring channelrhodopsins for such applications includes the tuning of the absorption maximum. In order to establish rational design and to obtain a desired spectral shift, a basic understanding of the absorption spectrum is required. We have studied the chimera C1C2 as a representative of this protein family and the first member with an available crystal structure. For this purpose, we sampled the conformations of C1C2 using quantum mechanical/molecular mechanical molecular dynamics and subjected the resulting snapshots of the trajectory to excitation energy calculations using ADC(2) and simplified time-dependent density functional theory. In contrast to previous reports, we found that different hydrogen-bonding networks-involving the retinal protonated Schiff base, the putative counterions E162 and D292, and water molecules-had only a small impact on the absorption spectrum. However, in the case of deprotonated E162, increasing the distance to the Schiff base hydrogen-bonding partner led to a systematic blue shift. The β-ionone ring rotation was identified as another important contributor. Yet the most important factors were found to be the bond length alternation and bond order alternation that were linearly correlated to the absorption maximum by up to 62 and 82%, respectively. We ascribe this novel insight into the structural basis of the absorption spectrum to our enhanced protein setup that includes membrane embedding as well as long and extensive sampling.
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Affiliation(s)
- Suliman Adam
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Christian Wiebeler
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
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26
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VanGordon MR, Prignano LA, Dempski RE, Rick SW, Rempe SB. Channelrhodopsin C1C2: Photocycle kinetics and interactions near the central gate. Biophys J 2021; 120:1835-1845. [PMID: 33705762 PMCID: PMC8204341 DOI: 10.1016/j.bpj.2021.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 12/27/2022] Open
Abstract
Channelrhodopsins (ChR) are light-sensitive cation channels used in optogenetics, a technique that applies light to control cells (e.g., neurons) that have been modified genetically to express those channels. Although mutations are known to affect pore kinetics, little is known about how mutations induce changes at the molecular scale. To address this issue, we first measured channel opening and closing rates of a ChR chimera (C1C2) and selected variants (N297D, N297V, and V125L). Then, we used atomistic simulations to correlate those rates with changes in pore structure, hydration, and chemical interactions among key gating residues of C1C2 in both closed and open states. Overall, the experimental results show that C1C2 and its mutants do not behave like ChR2 or its analogous variants, except V125L, making C1C2 a unique channel. Our atomistic simulations confirmed that opening of the channel and initial hydration of the gating regions between helices I, II, III, and VII of the channel occurs with 1) the presence of 13-cis retinal; 2) deprotonation of a glutamic acid gating residue, E129; and 3) subsequent weakening of the central gate hydrogen bond between the same glutamic acid E129 and asparagine N297 in the central region of the pore. Also, an aspartate (D292) is the unambiguous primary proton acceptor for the retinal Schiff base in the hydrated channel.
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Affiliation(s)
- Monika R VanGordon
- Department of Chemistry, University of New Orleans, New Orleans, Louisiana
| | - Lindsey A Prignano
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts
| | - Robert E Dempski
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts
| | - Steven W Rick
- Department of Chemistry, University of New Orleans, New Orleans, Louisiana
| | - Susan B Rempe
- Sandia National Laboratories, Albuquerque, New Mexico.
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27
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Oda K, Nomura T, Nakane T, Yamashita K, Inoue K, Ito S, Vierock J, Hirata K, Maturana AD, Katayama K, Ikuta T, Ishigami I, Izume T, Umeda R, Eguma R, Oishi S, Kasuya G, Kato T, Kusakizako T, Shihoya W, Shimada H, Takatsuji T, Takemoto M, Taniguchi R, Tomita A, Nakamura R, Fukuda M, Miyauchi H, Lee Y, Nango E, Tanaka R, Tanaka T, Sugahara M, Kimura T, Shimamura T, Fujiwara T, Yamanaka Y, Owada S, Joti Y, Tono K, Ishitani R, Hayashi S, Kandori H, Hegemann P, Iwata S, Kubo M, Nishizawa T, Nureki O. Time-resolved serial femtosecond crystallography reveals early structural changes in channelrhodopsin. eLife 2021; 10:62389. [PMID: 33752801 PMCID: PMC7987342 DOI: 10.7554/elife.62389] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 02/15/2021] [Indexed: 01/17/2023] Open
Abstract
Channelrhodopsins (ChRs) are microbial light-gated ion channels utilized in optogenetics to control neural activity with light . Light absorption causes retinal chromophore isomerization and subsequent protein conformational changes visualized as optically distinguished intermediates, coupled with channel opening and closing. However, the detailed molecular events underlying channel gating remain unknown. We performed time-resolved serial femtosecond crystallographic analyses of ChR by using an X-ray free electron laser, which revealed conformational changes following photoactivation. The isomerized retinal adopts a twisted conformation and shifts toward the putative internal proton donor residues, consequently inducing an outward shift of TM3, as well as a local deformation in TM7. These early conformational changes in the pore-forming helices should be the triggers that lead to opening of the ion conducting pore.
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Affiliation(s)
- Kazumasa Oda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Takashi Nomura
- Graduate School of Life Science, University of Hyogo, Hyogo, Japan
| | - Takanori Nakane
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Keitaro Yamashita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Keiichi Inoue
- Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Shota Ito
- Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Johannes Vierock
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Kunio Hirata
- RIKEN SPring-8 Center, Hyogo, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Kawaguchi, Japan
| | - Andrés D Maturana
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Kota Katayama
- Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Tatsuya Ikuta
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Itsuki Ishigami
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Tamaki Izume
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Rie Umeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Ryuun Eguma
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Satomi Oishi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Go Kasuya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Takafumi Kato
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Wataru Shihoya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Hiroto Shimada
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Tomoyuki Takatsuji
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Mizuki Takemoto
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Reiya Taniguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Atsuhiro Tomita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Ryoki Nakamura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Masahiro Fukuda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Hirotake Miyauchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yongchan Lee
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Eriko Nango
- RIKEN SPring-8 Center, Hyogo, Japan.,Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Rie Tanaka
- RIKEN SPring-8 Center, Hyogo, Japan.,Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tomoyuki Tanaka
- RIKEN SPring-8 Center, Hyogo, Japan.,Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | - Tetsunari Kimura
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Japan
| | - Tatsuro Shimamura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takaaki Fujiwara
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yasuaki Yamanaka
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shigeki Owada
- RIKEN SPring-8 Center, Hyogo, Japan.,Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Yasumasa Joti
- RIKEN SPring-8 Center, Hyogo, Japan.,Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Kensuke Tono
- RIKEN SPring-8 Center, Hyogo, Japan.,Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Ryuichiro Ishitani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Shigehiko Hayashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Hideki Kandori
- Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Peter Hegemann
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - So Iwata
- RIKEN SPring-8 Center, Hyogo, Japan.,Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Minoru Kubo
- Graduate School of Life Science, University of Hyogo, Hyogo, Japan
| | - Tomohiro Nishizawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Kawaguchi, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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28
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Structure-Function Relationship of Channelrhodopsins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1293:35-53. [PMID: 33398806 DOI: 10.1007/978-981-15-8763-4_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Ion-translocating rhodopsins, especially channelrhodopsins (ChRs), have attracted broad attention as a powerful tool to modulate the membrane potential of cells with light (optogenetics). Because of recent biophysical, spectroscopic, and computational studies, including the structural determination of cation and anion ChRs, our understanding of the molecular mechanism underlying light-gated ion conduction has been greatly advanced. In this chapter, I first describe the background of rhodopsin family proteins including ChR, and how the optogenetics technology has been established from the discovery of first ChR in 2002. I later introduce the recent findings of the structure-function relationship of ChR by comparing the crystal structures of cation and anion ChRs. I further discuss the future goal in the fields of ChR research and optogenetic tool development.
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29
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Time-resolved Infrared Characterization on the Photolysis of Roussin's Red Phenyl Ester in Different Solvents. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2020.113032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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30
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Walter M, Schlesinger R. Nanodisc Reconstitution of Channelrhodopsins Heterologously Expressed in Pichia pastoris for Biophysical Investigations. Methods Mol Biol 2021; 2191:29-48. [PMID: 32865737 DOI: 10.1007/978-1-0716-0830-2_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
For a successful characterization of channelrhodopsins with biophysical methods like FTIR, Raman, EPR and NMR spectroscopy and X-ray crystallography, large amounts of purified protein are requested. For proteins of eukaryotic origin, which are poorly expressing in bacterial systems or not at all, the yeast Pichia pastoris represents a promising alternative for overexpression. Here we describe the methods for cloning, overexpression and mutagenesis as well as the purification procedures for channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2), channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) and the scaffold protein MSP1D1 for reconstitution of the membrane proteins into nanodiscs. Finally, protocols are provided to study CaChR1 by FTIR difference spectroscopy and by time-resolved UV/Vis spectroscopy.
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Affiliation(s)
- Maria Walter
- Experimental Physics: Genetic Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Ramona Schlesinger
- Experimental Physics: Genetic Biophysics, Freie Universität Berlin, Berlin, Germany.
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31
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Cheng J, Zhang W, Zhou S, Ran X, Shang Y, Lo GV, Dou Y, Yuan S. The effect on ion channel of different protonation states of E90 in channelrhodopsin-2: a molecular dynamics simulation. RSC Adv 2021; 11:14542-14551. [PMID: 35424009 PMCID: PMC8697799 DOI: 10.1039/d1ra01879e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/13/2021] [Indexed: 11/21/2022] Open
Abstract
Channelrhodopsin-2 (ChR2) is a cationic channel protein that has been extensively studied in optogenetics. The ion channel is opened via a series of proton transfers and H-bond changes during the photocycle but the detailed mechanism is still unknown. Molecular dynamics (MD) simulations with enhanced sampling were performed on the dark-adapted state (i.e., D470) and two photocycle intermediates (P1500 and P2390) to study the proton transfer path of the Schiff base and the subsequent conformational changes. The results suggest there are two possible proton transfer pathways from the Schiff base to proton acceptors (i.e., E123 or D253), depending on the protonation of E90. If E90 is protonated in the P1500 state, the proton on the Schiff base will transfer to E123. The polyene chain of 13-cis retinal tilts and opens the channel that detours the blocking central gate (CG) and forms a narrow channel through the transmembrane helices (TM) 2, 3, 6 and 7. In contrast, if E90 deprotonates after retinal isomerization, the primary proton acceptor is D253, and an almost-open channel through TM1, 2, 3 and 7 is generated. The channel diameter is very close to the experimental value. The potential mean force (PMF) suggests that the free energy is extremely low for ions passing through this channel. With E90 protonated, the proton acceptor of RSBH+ is E123 with a narrow channel along TM3; while with E90 deprotonated, proton transfer from RSBH+ to D253 generates an approximately open channel along TM2.![]()
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Affiliation(s)
- Jie Cheng
- Chongqing Key Laboratory of Big Data for Bio Intelligence
- Chongqing University of Posts and Telecommunications
- Chongqing 40065
- China
| | - Wenying Zhang
- Chongqing Key Laboratory of Big Data for Bio Intelligence
- Chongqing University of Posts and Telecommunications
- Chongqing 40065
- China
| | - Shuangyan Zhou
- Chongqing Key Laboratory of Big Data for Bio Intelligence
- Chongqing University of Posts and Telecommunications
- Chongqing 40065
- China
| | - Xu Ran
- Chongqing Key Laboratory of Big Data for Bio Intelligence
- Chongqing University of Posts and Telecommunications
- Chongqing 40065
- China
| | - Yiwen Shang
- Chongqing Key Laboratory of Big Data for Bio Intelligence
- Chongqing University of Posts and Telecommunications
- Chongqing 40065
- China
| | - Glenn V. Lo
- Department of Chemistry and Physical Sciences
- Nicholls State University
- Thibodaux
- USA
| | - Yusheng Dou
- Department of Chemistry and Physical Sciences
- Nicholls State University
- Thibodaux
- USA
| | - Shuai Yuan
- Chongqing Key Laboratory of Big Data for Bio Intelligence
- Chongqing University of Posts and Telecommunications
- Chongqing 40065
- China
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32
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Cao Y, Yang R, Sun J, Zhang W, Lee I, Wang W, Meng X. Effects of amino acid modifications on the permeability of the pentameric sarcolipin channel. Proteins 2020; 89:427-435. [PMID: 33244801 DOI: 10.1002/prot.26028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/28/2020] [Accepted: 11/21/2020] [Indexed: 12/12/2022]
Abstract
Sarcolipin (SLN) is an important transmembrane (TM) protein encoded by long noncoding RNA. SLN is expressed in the sarcoplasmic reticulum and regulates cardiac and skeletal muscle contractions. SLN forms a pentameric hydrophobic ligand-gated ion channel. The protonation of Glu7 (protonated SLN, pSLN) and mutation of Thr18 to Ala18 (T18A) have been reported to exert a significant influence on the permeability of the channel. In this study, the altered permeability of both the pSLN and T18A pentameric channels was simulated. Combined with molecular dynamics simulation, the free-energy landscape for single ions, computational electrophysiology, diffusion coefficient, and pore geometrical characteristic analyses were performed to further understand the properties of amino acid modifications in the SLN pentameric channel. The results suggest that both the pSLN and T18A pentameric channels form stable hydrophobic ligand-gated channels. The TM voltage has a positive effect on the permeability of water molecules and ions. By using pSLN and T18A, our study provides helpful information on the pore-forming mechanism of SLN and furthers our understanding of the regulatory mechanisms underlying the permeation of ions and water molecules in the pentameric SLN channel.
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Affiliation(s)
- Yipeng Cao
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China.,National Supercomputer Center in Tianjin, TEDA - Tianjin Economic-Technological Development Area, Tianjin, China
| | - Rui Yang
- Department of Infection and Immunity, Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, China
| | - Jiana Sun
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Wenwen Zhang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Imshik Lee
- College of Physics, Nankai University, Tianjin, China
| | - Wei Wang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Xiangfei Meng
- National Supercomputer Center in Tianjin, TEDA - Tianjin Economic-Technological Development Area, Tianjin, China
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Nagasaka Y, Hososhima S, Kubo N, Nagata T, Kandori H, Inoue K, Yawo H. Gate-keeper of ion transport-a highly conserved helix-3 tryptophan in a channelrhodopsin chimera, C1C2/ChRWR. Biophys Physicobiol 2020; 17:59-70. [PMID: 33173715 PMCID: PMC7593130 DOI: 10.2142/biophysico.bsj-2020007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/27/2020] [Indexed: 12/01/2022] Open
Abstract
Microbial rhodopsin is a large family of membrane proteins having seven transmembrane helices (TM1-7) with an all-trans retinal (ATR) chromophore that is covalently bound to Lys in the TM7. The Trp residue in the middle of TM3, which is homologous to W86 of bacteriorhodopsin (BR), is highly conserved among microbial rhodopsins with various light-driven functions. However, the significance of this Trp for the ion transport function of microbial rhodopsins has long remained unknown. Here, we replaced the W163 (BR W86 counterpart) of a channelrhodopsin (ChR), C1C2/ChRWR, which is a chimera between ChR1 and 2, with a smaller aromatic residue, Phe to verify its role in the ion transport. Under whole-cell patch clamp recordings from the ND7/23 cells that were transfected with the DNA plasmid coding human codon optimized C1C2/ChRWR (hWR) or its W163F mutant (hWR-W163F), the photocurrents were evoked by a pulsatile light at 475 nm. The ion-transporting activity of hWR was strongly altered by the W163F mutation in 3 points: (1) the H+ leak at positive membrane potential (Vm) and its light-adaptation, (2) the attenuation of cation channel activity and (3) the manifestation of outward H+ pump activity. All of these results strongly suggest that W163 has a role in stabilizing the structure involved in the gating-on and -off of the cation channel, the role of “gate keeper”. We can attribute the attenuation of cation channel activity to the incomplete gating-on and the H+ leak to the incomplete gating-off.
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Affiliation(s)
- Yujiro Nagasaka
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.,Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Naoko Kubo
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.,Department of Physiology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan
| | - Takashi Nagata
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO) , Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya 466-8555, Japan.,OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Hiromu Yawo
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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34
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Charge Transport by Light-Activated Rhodopsins Determined by Electrophysiological Recordings. Methods Mol Biol 2020. [PMID: 32865739 DOI: 10.1007/978-1-0716-0830-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Electrophysiological experiments are required to determine the ion transport properties of light-activated currents from microbial rhodopsin expressing cells. The recordings set the quantitative basis for correlation with spectroscopic data and for understanding of channel gating, ion transport vectoriality, or ion selectivity. This chapter focuses on voltage-clamp recordings of channelrhodopsin-2-expressing cells, and it will describe different illumination protocols that reveal the kinetic properties of gating. While the opening and closing reaction is determined from a single turnover upon a short laser flash, desensitization of the light-gated currents is studied under continuous illumination. Recovery from the desensitized state is probed after prolonged illumination with a subsequent light activation upon different dark intervals. Compiling the experimental data will define a minimum number of states in kinetic schemes used to describe the light-gated currents in channelrhodopsins, and emphasis will be given on how to correlate the results with the different time-resolved spectroscopic experiments.
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35
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Probing the Proton-Loading Site of Cytochrome C Oxidase Using Time-Resolved Fourier Transform Infrared Spectroscopy. Molecules 2020; 25:molecules25153393. [PMID: 32727022 PMCID: PMC7435947 DOI: 10.3390/molecules25153393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 01/08/2023] Open
Abstract
Crystal structure analyses at atomic resolution and FTIR spectroscopic studies of cytochrome c oxidase have yet not revealed protonation or deprotonation of key sites of proton transfer in a time-resolved mode. Here, a sensitive technique to detect protolytic transitions is employed. In this work, probing a proton-loading site of cytochrome c oxidase from Paracoccus denitrificans with time-resolved Fourier transform infrared spectroscopy is presented for the first time. For this purpose, variants with single-site mutations of N131V, D124N, and E278Q, the key residues in the D-channel, were studied. The reaction of mutated CcO enzymes with oxygen was monitored and analyzed. Seven infrared bands in the “fast” kinetic spectra were found based on the following three requirements: (1) they are present in the “fast” phases of N131V and D124N mutants, (2) they have reciprocal counterparts in the “slow” kinetic spectra in these mutants, and (3) they are absent in “fast” kinetic spectra of the E278Q mutant. Moreover, the double-difference spectra between the first two mutants and E278Q revealed more IR bands that may belong to the proton-loading site protolytic transitions. From these results, it is assumed that several polar residues and/or water molecule cluster(s) share a proton as a proton-loading site. This site can be propionate itself (holding only a fraction of H+), His403, and/or water cluster(s).
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36
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Forelimb movements evoked by optogenetic stimulation of the macaque motor cortex. Nat Commun 2020; 11:3253. [PMID: 32591505 PMCID: PMC7319997 DOI: 10.1038/s41467-020-16883-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 05/28/2020] [Indexed: 12/15/2022] Open
Abstract
Optogenetics has become an indispensable tool for investigating brain functions. Although non-human primates are particularly useful models for understanding the functions and dysfunctions of the human brain, application of optogenetics to non-human primates is still limited. In the present study, we generate an effective adeno-associated viral vector serotype DJ to express channelrhodopsin-2 (ChR2) under the control of a strong ubiquitous CAG promoter and inject into the somatotopically identified forelimb region of the primary motor cortex in macaque monkeys. ChR2 is strongly expressed around the injection sites, and optogenetic intracortical microstimulation (oICMS) through a homemade optrode induces prominent cortical activity: Even single-pulse, short-duration oICMS evokes long-lasting repetitive firings of cortical neurons. In addition, oICMS elicits distinct forelimb movements and muscle activity, which are comparable to those elicited by conventional electrical ICMS. The present study removes obstacles to optogenetic manipulation of neuronal activity and behaviors in non-human primates. Non-human primates are useful models for understanding the human brain but application of optogenetics to non-human primates is challenging. The authors used optogenetic intracortical microstimulation in the primary motor cortex of macaques to elicit distinct forelimb movements and muscle activity.
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37
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Femtosecond-to-millisecond structural changes in a light-driven sodium pump. Nature 2020; 583:314-318. [DOI: 10.1038/s41586-020-2307-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/16/2020] [Indexed: 01/03/2023]
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38
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Abstract
Infrared difference spectroscopy probes vibrational changes of proteins upon their perturbation. Compared with other spectroscopic methods, it stands out by its sensitivity to the protonation state, H-bonding, and the conformation of different groups in proteins, including the peptide backbone, amino acid side chains, internal water molecules, or cofactors. In particular, the detection of protonation and H-bonding changes in a time-resolved manner, not easily obtained by other techniques, is one of the most successful applications of IR difference spectroscopy. The present review deals with the use of perturbations designed to specifically change the protein between two (or more) functionally relevant states, a strategy often referred to as reaction-induced IR difference spectroscopy. In the first half of this contribution, I review the technique of reaction-induced IR difference spectroscopy of proteins, with special emphasis given to the preparation of suitable samples and their characterization, strategies for the perturbation of proteins, and methodologies for time-resolved measurements (from nanoseconds to minutes). The second half of this contribution focuses on the spectral interpretation. It starts by reviewing how changes in H-bonding, medium polarity, and vibrational coupling affect vibrational frequencies, intensities, and bandwidths. It is followed by band assignments, a crucial aspect mostly performed with the help of isotopic labeling and site-directed mutagenesis, and complemented by integration and interpretation of the results in the context of the studied protein, an aspect increasingly supported by spectral calculations. Selected examples from the literature, predominately but not exclusively from retinal proteins, are used to illustrate the topics covered in this review.
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39
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Hososhima S, Shigemura S, Kandori H, Tsunoda SP. Novel optogenetics tool: Gt_CCR4, a light-gated cation channel with high reactivity to weak light. Biophys Rev 2020; 12:453-459. [PMID: 32166612 DOI: 10.1007/s12551-020-00676-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/02/2020] [Indexed: 12/12/2022] Open
Abstract
Optogenetics is a growing technique which allows manipulation of biological events simply by illumination. The technique is appreciated especially in the neuroscience field because of its availability in controlling neuronal functions. A light-gated cation channel, Cr_ChR2 from Chlamydomonas reinhardtii, is the first and mostly applied to optogenetics for activating neuronal excitability. In addition, the molecular mechanism of Cr_ChR2 has been intensively studied by electrophysiology, spectroscopy, X-ray structural studies, etc. Novel cation channelrhodopsins from Guillardia theta, namely, Gt_CCR1-4, were discovered in 2016 and 2017. These channelrhodopsins are more homologous to haloarchaeal rhodopsins, particularly the proton pumps. Thus these cryptophyte-type light-gated cation channels are structurally and mechanistically distinct from chlorophyte channelrhodopsin such as Cr_ChR2. We here compared the photocurrent properties, cation selectivity, and kinetics between well-known Cr_ChR2 and Gt_CCR4. The light sensitivity of Gt_CCR4 is significantly higher than that of Cr_ChR2, while the channel open lifetime is in the same range as that of Cr_ChR2. Gt_CCR4 shows high Na+ selectivity in which the selectivity ratio for Na+ was 37-fold larger than that for Cr_ChR2, which primarily conducts H+. On the other hand, Gt_CCR4 conducted almost no H+ and no Ca2+ under physiological conditions. Other unique features and the applicability of Gt_CCR4 for optogenetics were discussed.
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Affiliation(s)
- Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
| | - Shunta Shigemura
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan.,OptoBio Technology Research Center, 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. .,PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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40
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Ritter E, Puskar L, Kim SY, Park JH, Hofmann KP, Bartl F, Hegemann P, Schade U. Féry Infrared Spectrometer for Single-Shot Analysis of Protein Dynamics. J Phys Chem Lett 2019; 10:7672-7677. [PMID: 31763851 DOI: 10.1021/acs.jpclett.9b03099] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Current submillisecond time-resolved broad-band infrared spectroscopy, one of the most frequently used techniques for studying structure-function relationships in life sciences, is typically limited to fast-cycling reactions that can be repeated thousands of times with high frequency. Notably, a majority of chemical and biological processes do not comply with this requirement. For example, the activation of vertebrate rhodopsin, a prototype of many protein receptors in biological organisms that mediate basic functions of life, including vision, smell, and taste, is irreversible. Here we present a dispersive single-shot Féry spectrometer setup that extends such spectroscopy to irreversible and slow-cycling systems by exploiting the unique properties of brilliant synchrotron infrared light combined with an advanced focal plane detector array embedded in a dispersive optical concept. We demonstrate our single-shot method on microbial actinorhodopsin with a slow photocycle and on vertebrate rhodopsin with irreversible activation.
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Affiliation(s)
- Eglof Ritter
- Humboldt-Universität zu Berlin , Experimentelle Biophysik , 10115 Berlin , Germany
- Humboldt-Universität zu Berlin , Biophysikalische Chemie , 10115 Berlin , Germany
| | - Ljiljana Puskar
- Helmholtz-Zentrum Berlin für Materialien und Energie , 12498 Berlin , Germany
| | - So Young Kim
- Chonbuk National University , Division of Biotechnology, Advanced Institute of Environment and Bioscience , 54596 Iksan , Republic of Korea
| | - Jung Hee Park
- Chonbuk National University , Division of Biotechnology, Advanced Institute of Environment and Bioscience , 54596 Iksan , Republic of Korea
| | | | - Franz Bartl
- Humboldt-Universität zu Berlin , Biophysikalische Chemie , 10115 Berlin , Germany
| | - Peter Hegemann
- Humboldt-Universität zu Berlin , Experimentelle Biophysik , 10115 Berlin , Germany
| | - Ulrich Schade
- Helmholtz-Zentrum Berlin für Materialien und Energie , 12498 Berlin , Germany
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41
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Molecular Dynamics Simulation of Transmembrane Transport of Chloride Ions in Mutants of Channelrhodopsin. Biomolecules 2019; 9:biom9120852. [PMID: 31835536 PMCID: PMC6995576 DOI: 10.3390/biom9120852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/01/2019] [Accepted: 12/06/2019] [Indexed: 01/12/2023] Open
Abstract
Channelrhodopsins (ChRs) are light-gated transmembrane cation channels which are widely used for optogenetic technology. Replacing glutamate located at the central gate of the ion channel with positively charged amino acid residues will reverse ion selectivity and allow anion conduction. The structures and properties of the ion channel, the transport of chloride, and potential of mean force (PMF) of the chimera protein (C1C2) and its mutants, EK-TC, ER-TC and iChloC, were investigated by molecular dynamics simulation. The results show that the five-fold mutation in E122Q-E129R-E140S-D195N-T198C (iChloC) increases the flexibility of the transmembrane channel protein better than the double mutations in EK-TC and ER-TC, and results in an expanded ion channel pore size and decreased steric resistance. The iChloC mutant was also found to have a higher affinity for chloride ions and, based on surface electrostatic potential analysis, provides a favorable electrostatic environment for anion conduction. The PMF free energy curves revealed that high affinity Cl- binding sites are generated near the central gate of the three mutant proteins. The energy barriers for the EK-TC and ER-TC were found to be much higher than that of iChloC. The results suggest that the transmembrane ion channel of iChloC protein is better at facilitating the capture and transport of chloride ions.
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42
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Atomistic Insight into the Role of Threonine 127 in the Functional Mechanism of Channelrhodopsin-2. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9224905] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Channelrhodopsins (ChRs) belong to the unique class of light-gated ion channels. The structure of channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2) has been resolved, but the mechanistic link between light-induced isomerization of the chromophore retinal and channel gating remains elusive. Replacements of residues C128 and D156 (DC gate) resulted in drastic effects in channel closure. T127 is localized close to the retinal Schiff base and links the DC gate to the Schiff base. The homologous residue in bacteriorhodopsin (T89) has been shown to be crucial for the visible absorption maximum and dark–light adaptation, suggesting an interaction with the retinylidene chromophore, but the replacement had little effect on photocycle kinetics and proton pumping activity. Here, we show that the T127A and T127S variants of CrChR2 leave the visible absorption maximum unaffected. We inferred from hybrid quantum mechanics/molecular mechanics (QM/MM) calculations and resonance Raman spectroscopy that the hydroxylic side chain of T127 is hydrogen-bonded to E123 and the latter is hydrogen-bonded to the retinal Schiff base. The C=N–H vibration of the Schiff base in the T127A variant was 1674 cm−1, the highest among all rhodopsins reported to date. We also found heterogeneity in the Schiff base ground state vibrational properties due to different rotamer conformations of E123. The photoreaction of T127A is characterized by a long-lived P2380 state during which the Schiff base is deprotonated. The conservative replacement of T127S hardly affected the photocycle kinetics. Thus, we inferred that the hydroxyl group at position 127 is part of the proton transfer pathway from D156 to the Schiff base during rise of the P3530 intermediate. This finding provides molecular reasons for the evolutionary conservation of the chemically homologous residues threonine, serine, and cysteine at this position in all channelrhodopsins known so far.
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43
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Siemers M, Lazaratos M, Karathanou K, Guerra F, Brown LS, Bondar AN. Bridge: A Graph-Based Algorithm to Analyze Dynamic H-Bond Networks in Membrane Proteins. J Chem Theory Comput 2019; 15:6781-6798. [DOI: 10.1021/acs.jctc.9b00697] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Malte Siemers
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany
| | - Michalis Lazaratos
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany
| | - Konstantina Karathanou
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany
| | - Federico Guerra
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany
| | - Leonid S. Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany
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44
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Senger M, Eichmann V, Laun K, Duan J, Wittkamp F, Knör G, Apfel UP, Happe T, Winkler M, Heberle J, Stripp ST. How [FeFe]-Hydrogenase Facilitates Bidirectional Proton Transfer. J Am Chem Soc 2019; 141:17394-17403. [PMID: 31580662 PMCID: PMC6823627 DOI: 10.1021/jacs.9b09225] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Hydrogenases are metalloenzymes that
catalyze the conversion of
protons and molecular hydrogen, H2. [FeFe]-hydrogenases
show particularly high rates of hydrogen turnover and have inspired
numerous compounds for biomimetic H2 production. Two decades
of research on the active site cofactor of [FeFe]-hydrogenases have
put forward multiple models of the catalytic proceedings. In comparison,
our understanding of proton transfer is poor. Previously, residues
were identified forming a hydrogen-bonding network between active
site cofactor and bulk solvent; however, the exact mechanism of catalytic
proton transfer remained inconclusive. Here, we employ in
situ infrared difference spectroscopy on the [FeFe]-hydrogenase
from Chlamydomonas reinhardtii evaluating dynamic
changes in the hydrogen-bonding network upon photoreduction. While
proton transfer appears to be impaired in the oxidized state (Hox), the presented data support continuous proton transfer
in the reduced state (Hred). Our analysis allows for
a direct, molecular unique assignment to individual amino acid residues.
We found that transient protonation changes of glutamic acid residue
E141 and, most notably, arginine R148 facilitate bidirectional proton
transfer in [FeFe]-hydrogenases.
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Affiliation(s)
- Moritz Senger
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Viktor Eichmann
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Konstantin Laun
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | | | | | - Günther Knör
- Institute of Inorganic Chemistry , Johannes Kepler Universität Linz , Altenberger Straße 69 , 4040 Linz , Austria
| | | | | | | | - Joachim Heberle
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Sven Timo Stripp
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
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Abstract
We previously reported a cation channelrhodopsin, Gt_CCR4, which is one of the 44 types of microbial rhodopsins from a cryptophyte flagellate, Guillardia theta. Due to the modest homology of amino acid sequences with a chlorophyte channelrhodopsin such as Cr_ChR2 from Chlamydomonas reinhardtii, it has been proposed that a family of cryptophyte channelrhodopsin, including Gt_CCR4, has a distinct molecular mechanism for channel gating and ion permeation. In this study, we compared the photocurrent properties, cation selectivity and kinetics between well-known Cr_ChR2 and Gt_CCR4 by a conventional path clamp method. Large and stable light-induced cation conduction by Gt_CCR4 at the maximum absorbing wavelength (530 nm) was observed with only small inactivation (15%), whereas the photocurrent of Cr_ChR2 exhibited significant inactivation (50%) and desensitization. The light sensitivity of Gt_CCR4 was higher (EC50 = 0.13 mW/mm2) than that of Cr_ChR2 (EC50 = 0.80 mW/mm2) while the channel open life time (photocycle speed) was in the same range as that of Cr_ChR2 (25~30 ms for Gt_CCR4 and 10~15 ms for Cr_ChR2). This observation implies that Gt_CCR4 enables optical neuronal spiking with weak light in high temporal resolution when applied in neuroscience. Furthermore, we demonstrated high Na+ selectivity of Gt_CCR4 in which the selectivity ratio for Na+ was 37-fold larger than that for Cr_ChR2, which primarily conducts H+. On the other hand, Gt_CCR4 conducted almost no H+ and no Ca2+ under physiological conditions. These results suggest that ion selectivity in Gt_CCR4 is distinct from that in Cr_ChR2. In addition, a unique red-absorbing and stable intermediate in the photocycle was observed, indicating a photochromic property of Gt_CCR4.
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46
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Liang R, Liu F, Martínez TJ. Nonadiabatic Photodynamics of Retinal Protonated Schiff Base in Channelrhodopsin 2. J Phys Chem Lett 2019; 10:2862-2868. [PMID: 31083920 DOI: 10.1021/acs.jpclett.9b00701] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Channelrhodopsin 2 (ChR2) is a light-gated ion channel and an important tool in optogenetics. Photoisomerization of retinal protonated Schiff base (RPSB) in ChR2 triggers channel activation. Despite the importance of ChR2 in optogenetics, the detailed mechanism for photoisomerization and channel activation is still not fully understood. Here, we report on computer simulations to investigate the photoisomerization mechanism and its effect on the activation of ChR2. Nonadiabatic dynamics simulation of ChR2 was carried out using the ab initio multiple spawning (AIMS) method and quantum mechanics/molecular mechanics (QM/MM) with a restricted ensemble Kohn-Sham (REKS) treatment of the QM region. Our results agree well with spectroscopic measurements and reveal that the RPSB isomerization is highly specific around the C13=C14 bond and follows the "aborted bicycle-pedal" mechanism. In addition, RPSB photoisomerization facilitates its deprotonation and partially increases the hydration level in the channel, which could trigger subsequent channel opening and ion conduction.
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Affiliation(s)
- Ruibin Liang
- Department of Chemistry and The PULSE Institute , Stanford University , Stanford , California 94305 , United States
- SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
| | - Fang Liu
- Department of Chemistry and The PULSE Institute , Stanford University , Stanford , California 94305 , United States
- SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
| | - Todd J Martínez
- Department of Chemistry and The PULSE Institute , Stanford University , Stanford , California 94305 , United States
- SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
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47
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Unifying photocycle model for light adaptation and temporal evolution of cation conductance in channelrhodopsin-2. Proc Natl Acad Sci U S A 2019; 116:9380-9389. [PMID: 31004059 PMCID: PMC6510988 DOI: 10.1073/pnas.1818707116] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Although channelrhodopsin (ChR) is a widely applied light-activated ion channel, important properties such as light adaptation, photocurrent inactivation, and alteration of the ion selectivity during continuous illumination are not well understood from a molecular perspective. Herein, we address these open questions using single-turnover electrophysiology, time-resolved step-scan FTIR, and Raman spectroscopy of fully dark-adapted ChR2. This yields a unifying parallel photocycle model integrating now all so far controversial discussed data. In dark-adapted ChR2, the protonated retinal Schiff base chromophore (RSBH+) adopts an all-trans,C=N-anti conformation only. Upon light activation, a branching reaction into either a 13-cis,C=N-anti or a 13-cis,C=N-syn retinal conformation occurs. The anti-cycle features sequential H+ and Na+ conductance in a late M-like state and an N-like open-channel state. In contrast, the 13-cis,C=N-syn isomer represents a second closed-channel state identical to the long-lived P480 state, which has been previously assigned to a late intermediate in a single-photocycle model. Light excitation of P480 induces a parallel syn-photocycle with an open-channel state of small conductance and high proton selectivity. E90 becomes deprotonated in P480 and stays deprotonated in the C=N-syn cycle. Deprotonation of E90 and successive pore hydration are crucial for late proton conductance following light adaptation. Parallel anti- and syn-photocycles now explain inactivation and ion selectivity changes of ChR2 during continuous illumination, fostering the future rational design of optogenetic tools.
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Ehrenberg D, Varma N, Deupi X, Koyanagi M, Terakita A, Schertler GFX, Heberle J, Lesca E. The Two-Photon Reversible Reaction of the Bistable Jumping Spider Rhodopsin-1. Biophys J 2019; 116:1248-1258. [PMID: 30902364 PMCID: PMC6451042 DOI: 10.1016/j.bpj.2019.02.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/16/2019] [Accepted: 02/19/2019] [Indexed: 12/22/2022] Open
Abstract
Bistable opsins are photopigments expressed in both invertebrates and vertebrates. These light-sensitive G-protein-coupled receptors undergo a reversible reaction upon illumination. A first photon initiates the cis to trans isomerization of the retinal chromophore—attached to the protein through a protonated Schiff base—and a series of transition states that eventually results in the formation of the thermally stable and active Meta state. Excitation by a second photon reverts this process to recover the original ground state. On the other hand, monostable opsins (e.g., bovine rhodopsin) lose their chromophore during the decay of the Meta II state (i.e., they bleach). Spectroscopic studies on the molecular details of the two-photon cycle in bistable opsins are limited. Here, we describe the successful expression and purification of recombinant rhodopsin-1 from the jumping spider Hasarius adansoni (JSR1). In its natural configuration, spectroscopic characterization of JSR1 is hampered by the similar absorption spectra in the visible spectrum of the inactive and active states. We solved this issue by separating their absorption spectra by replacing the endogenous 11-cis retinal chromophore with the blue-shifted 9-cis JSiR1. With this system, we used time-resolved ultraviolet-visible spectroscopy after pulsed laser excitation to obtain kinetic details of the rise and decay of the photocycle intermediates. We also used resonance Raman spectroscopy to elucidate structural changes of the retinal chromophore upon illumination. Our data clearly indicate that the protonated Schiff base is stable throughout the entire photoreaction. We additionally show that the accompanying conformational changes in the protein are different from those of monostable rhodopsin, as recorded by light-induced FTIR difference spectroscopy. Thus, we envisage JSR1 as becoming a model system for future studies on the reaction mechanisms of bistable opsins, e.g., by time-resolved x-ray crystallography.
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Affiliation(s)
- David Ehrenberg
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Berlin, Germany
| | - Niranjan Varma
- Division of Biology and Chemistry-Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland; Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Xavier Deupi
- Division of Neutrons and Muons-Laboratory for Scientific Computing and Modelling, Paul Scherrer Institute, Villigen, Switzerland
| | - Mitsumasa Koyanagi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Akihisa Terakita
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Gebhard F X Schertler
- Division of Biology and Chemistry-Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland; Department of Biology, ETH Zürich, Zürich, Switzerland.
| | - Joachim Heberle
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Berlin, Germany.
| | - Elena Lesca
- Division of Biology and Chemistry-Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland; Department of Biology, ETH Zürich, Zürich, Switzerland.
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Watari M, Ikuta T, Yamada D, Shihoya W, Yoshida K, Tsunoda SP, Nureki O, Kandori H. Spectroscopic study of the transmembrane domain of a rhodopsin-phosphodiesterase fusion protein from a unicellular eukaryote. J Biol Chem 2019; 294:3432-3443. [PMID: 30622140 DOI: 10.1074/jbc.ra118.006277] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/31/2018] [Indexed: 02/02/2023] Open
Abstract
The choanoflagellate Salpingoeca rosetta contains a chimeric rhodopsin protein composed of an N-terminal rhodopsin (Rh) domain and a C-terminal cyclic nucleotide phosphodiesterase (PDE) domain. The Rh-PDE enzyme light-dependently decreases the concentrations of cyclic nucleotides such as cGMP and cAMP. Photoexcitation of purified full-length Rh-PDE yields an "M" intermediate with a deprotonated Schiff base, and its recovery is much faster than that of the enzyme domain. To gain structural and mechanistic insights into the Rh domain, here we expressed and purified the transmembrane domain of Rh-PDE, Rh-PDE(TMD), and analyzed it with transient absorption, light-induced difference UV-visible, and FTIR spectroscopy methods. These analyses revealed that the "K" intermediate forms within 0.005 ms and converts into the M intermediate with a time constant of 4 ms, with the latter returning to the original state within 4 s. FTIR spectroscopy revealed that all-trans to 13-cis photoisomerization occurs as the primary event during which chromophore distortion is located at the middle of the polyene chain, allowing the Schiff base to form a stronger hydrogen bond. We also noted that the peptide backbone of the α-helix becomes deformed upon M intermediate formation. Results from site-directed mutagenesis suggested that Glu-164 is protonated and that Asp-292 acts as the only Schiff base counterion in Rh-PDE. A strong reduction of enzymatic activity in a D292N variant, but not in an E164Q variant, indicated an important catalytic role of the negative charge at Asp-292. Our findings provide further mechanistic insights into rhodopsin-mediated, light-dependent regulation of second-messenger levels in eukaryotic microbes.
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Affiliation(s)
- Masahito Watari
- From the Department of Life Science and Applied Chemistry and
| | - Tatsuya Ikuta
- the Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan, and
| | - Daichi Yamada
- From the Department of Life Science and Applied Chemistry and
| | - Wataru Shihoya
- the Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan, and
| | - Kazuho Yoshida
- From the Department of Life Science and Applied Chemistry and
| | - Satoshi P Tsunoda
- From the Department of Life Science and Applied Chemistry and.,the OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.,PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Osamu Nureki
- the Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan, and
| | - Hideki Kandori
- From the Department of Life Science and Applied Chemistry and .,the OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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50
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Bühl E, Eberhardt P, Bamann C, Bamberg E, Braun M, Wachtveitl J. Ultrafast Protein Response in Channelrhodopsin-2 Studied by Time-Resolved Infrared Spectroscopy. J Phys Chem Lett 2018; 9:7180-7184. [PMID: 30525663 DOI: 10.1021/acs.jpclett.8b03382] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ultrafast infrared transient absorption in the carbonyl vibrational region of protonated aspartate and glutamate residues in channelrhodopsin-2 from Chlamydomonas reinhardtii shows immediate protein response to retinal excitation. The observed difference bands are formed directly after the excitation on the subpicosecond time scale and were assigned to side chains in the retinal vicinity, such as D156 and E90. This finding implies an ultrafast and effective energy transfer from the retinal to its environment via hydrogen-bonded networks and reveals extraordinarily strong chromophore-protein coupling and intense interaction within the protein. Relevance to the protein function as an optically gated ion channel is discussed.
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Affiliation(s)
- Elena Bühl
- Institute of Physical and Theoretical Chemistry , Goethe University , Max von Laue-Straße 7 , 60438 Frankfurt am Main , Germany
| | - Peter Eberhardt
- Institute of Physical and Theoretical Chemistry , Goethe University , Max von Laue-Straße 7 , 60438 Frankfurt am Main , Germany
| | - Christian Bamann
- Max Planck Institute of Biophysics , Max von Laue-Straße 3 , 60438 Frankfurt am Main , Germany
| | - Ernst Bamberg
- Max Planck Institute of Biophysics , Max von Laue-Straße 3 , 60438 Frankfurt am Main , Germany
| | - Markus Braun
- Institute of Physical and Theoretical Chemistry , Goethe University , Max von Laue-Straße 7 , 60438 Frankfurt am Main , Germany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical Chemistry , Goethe University , Max von Laue-Straße 7 , 60438 Frankfurt am Main , Germany
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