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Hour C, Chuon K, Song MC, Shim JG, Cho SG, Kang KW, Kim JH, Jung KH. Unveiling the critical role of K + for xanthorhodopsin expression in E. coli. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 258:112976. [PMID: 39002191 DOI: 10.1016/j.jphotobiol.2024.112976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 06/19/2024] [Accepted: 07/01/2024] [Indexed: 07/15/2024]
Abstract
Xanthorhodopsin (XR), a retinal-binding 7-transmembrane protein isolated from the eubacterium Salinibacter ruber, utilizes two chromophores (retinal and salinixanthin (SAL)) as an outward proton pump and energy-donating carotenoid. However, research on XR has been impeded owing to limitations in achieving heterogeneous expression of stable forms and high production levels of both wild-type and mutants. We successfully expressed wild-type and mutant XRs in Escherichia coli in the presence of K+. Achieving XR expression requires significant K+ and a low inducer concentration. In particular, we highlight the significance of Ser-159 in helix E located near Gly-156 (a carotenoid-binding position) as a critical site for XR expression. Our findings indicate that replacing Ser-159 with a smaller amino acid, alanine, can enhance XR expression in a manner comparable to K+, implying that Ser-159 poses a steric hindrance for pigment formation in XR. In the presence of K+, the proton pumping and photocycle of the wild-type and mutants were characterized and compared; the wild-type result suggests similar properties to the first reported XR isolation from the S. ruber membrane fraction. We propose that the K+ gradient across the cell membrane of S. ruber serves to uphold the membrane potential of the organism and plays a role in the expression of proteins, such as XR, as demonstrated in our study. Our findings deepen the understanding of adaptive protein expression, particularly in halophilic organisms. We highlight salt selection as a promising strategy for improving protein yield and functionality.
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Affiliation(s)
- Chenda Hour
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Kimleng Chuon
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Myung-Chul Song
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Jin-Gon Shim
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Shin-Gyu Cho
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea; Research Institute for Basic Science, Sogang University, Seoul, Republic of Korea
| | - Kun-Wook Kang
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Ji-Hyun Kim
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Kwang-Hwan Jung
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea.
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2
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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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3
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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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4
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Jefcoat HJ, Stenger CL, Terwilliger L, Morris M, Morris O. D130A variant on Parkinson 22-related CHCHD2 is predicted to have decreased protein movement. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.001093. [PMID: 38188421 PMCID: PMC10770730 DOI: 10.17912/micropub.biology.001093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/12/2023] [Accepted: 12/15/2023] [Indexed: 01/09/2024]
Abstract
Parkinson's disease is the second most common neurodegenerative disease which is caused by a lack of dopamine in the brain. Parkinson 22 is a form of Parkinson's disease caused by variations in the coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2) protein. This study investigates an aspartic acid-to-alanine swap on amino acid position 130 (D130A) of the CHCHD2 protein. We have employed protein modeling, conservation analysis, and molecular dynamics simulations to gain an understanding of the effects of the D130A variant on CHCHD2 protein structure and movement.
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Affiliation(s)
- Hanna J. Jefcoat
- Biology, University of North Alabama, Florence, Alabama, United States
| | - Cynthia L. Stenger
- Mathematics, University of North Alabama, Florence, Alabama, United States
| | - Luke Terwilliger
- Computer Science, University of North Alabama, Florence, Alabama, United States
| | - Michele Morris
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, United States
| | - Olivia Morris
- Biology, University of North Alabama, Florence, Alabama, United States
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Marín MDC, Jaffe AL, West PT, Konno M, Banfield JF, Inoue K. Biophysical characterization of microbial rhodopsins with DSE motif. Biophys Physicobiol 2023; 20:e201023. [PMID: 38362324 PMCID: PMC10865882 DOI: 10.2142/biophysico.bppb-v20.s023] [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: 02/01/2023] [Accepted: 03/07/2023] [Indexed: 03/09/2023] Open
Abstract
Microbial rhodopsins are photoreceptive transmembrane proteins that transport ions or regulate other intracellular biological processes. Recent genomic and metagenomic analyses found many microbial rhodopsins with unique sequences distinct from known ones. Functional characterization of these new types of microbial rhodopsins is expected to expand our understanding of their physiological roles. Here, we found microbial rhodopsins having a DSE motif in the third transmembrane helix from members of the Actinobacteria. Although the expressed proteins exhibited blue-green light absorption, either no or extremely small outward H+ pump activity was observed. The turnover rate of the photocycle reaction of the purified proteins was extremely slow compared to typical H+ pumps, suggesting these rhodopsins would work as photosensors or H+ pumps whose activities are enhanced by an unknown regulatory system in the hosts. The discovery of this rhodopsin group with the unique motif and functionality expands our understanding of the biological role of microbial rhodopsins.
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Affiliation(s)
- María del Carmen Marín
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Alexander L. Jaffe
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA
- Department of Earth System Science, Stanford University, Stanford, CA 94305-4216, USA
| | - Patrick T. West
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA
| | - Masae Konno
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Jillian F. Banfield
- Innovative Genomics Institute, University of California, Berkeley, CA 94720-2151, USA
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720-4767, USA
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720-3114, USA
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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6
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Broser M. Far-Red Absorbing Rhodopsins, Insights From Heterodimeric Rhodopsin-Cyclases. Front Mol Biosci 2022; 8:806922. [PMID: 35127823 PMCID: PMC8815786 DOI: 10.3389/fmolb.2021.806922] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
The recently discovered Rhodopsin-cyclases from Chytridiomycota fungi show completely unexpected properties for microbial rhodopsins. These photoreceptors function exclusively as heterodimers, with the two subunits that have very different retinal chromophores. Among them is the bimodal photoswitchable Neorhodopsin (NeoR), which exhibits a near-infrared absorbing, highly fluorescent state. These are features that have never been described for any retinal photoreceptor. Here these properties are discussed in the context of color-tuning approaches of retinal chromophores, which have been extensively studied since the discovery of the first microbial rhodopsin, bacteriorhodopsin, in 1971 (Oesterhelt et al., Nature New Biology, 1971, 233 (39), 149–152). Further a brief review about the concept of heterodimerization is given, which is widely present in class III cyclases but is unknown for rhodopsins. NIR-sensitive retinal chromophores have greatly expanded our understanding of the spectral range of natural retinal photoreceptors and provide a novel perspective for the development of optogenetic tools.
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Cho SG, Shim JG, Choun K, Meas S, Kang KW, Kim JH, Cho HS, Jung KH. Discovery of a new light-driven Li +/Na +-pumping rhodopsin with DTG motif. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2021; 223:112285. [PMID: 34411952 DOI: 10.1016/j.jphotobiol.2021.112285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/31/2021] [Accepted: 08/10/2021] [Indexed: 11/17/2022]
Abstract
Microbial pumping rhodopsin is a seven-transmembrane retinal binding protein, which is light-driven ion pump with a functional key motif. Ion-pumping with the key motif and charged amino acids in the rhodopsin is biochemically important. The rhodopsins with DTG motif have been discovered in various eubacteria, and they function as H+ pump. Especially, the DTG motif rhodopsins transported H+ despite the replacement of a proton donor by Gly. We investigated Methylobacterium populi rhodopsin (MpR) in one of the DTG motif rhodopsin clades. To determine which ions the MpR transport, we tested with various monovalent ion solutions and determined that MpR transports Li+/Na+. By replacing the three negatively charged residues residues which are located in helix B, Glu32, Glu33, and Asp35, we concluded that the residues play a critical role in the transport of Li+/Na+. The MpR E33Q transported H+ in place of Li+/Na+, suggesting that Glu33 is a Li+/Na+ binding site on the cytoplasmic side. Gly93 in MpR was replaced by Asp to convert from the Li+/Na+ pump to the H+ pump, resulting in MpR G93D transporting H+. Dissociation constant (Kd) values of Na+ for MpR WT and E33Q were determined to be 4.0 and 72.5 mM, respectively. These results indicated the mechanism by which MpR E33Q transports H+. Up to now, various ion-pumping rhodopsins have been discovered, and Li+/Na+-pumping rhodopsins were only found in the NDQ motif in NaR. Here, we report a new light-driven Na+ pump MpR and have determined the important residues required for Li+/Na+-pumping different from previously known NaR.
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Affiliation(s)
- Shin-Gyu Cho
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul 04107, Republic of Korea
| | - Jin-Gon Shim
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul 04107, Republic of Korea
| | - Kimleng Choun
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul 04107, Republic of Korea
| | - Seanghun Meas
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul 04107, Republic of Korea; Department of Biology, Faculty of Science, Royal University of Phnom Penh, Phnom Penh 12000, Cambodia
| | - Kun-Wook Kang
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul 04107, Republic of Korea
| | - Ji-Hyun Kim
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul 04107, Republic of Korea
| | - Hyun-Suk Cho
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul 04107, Republic of Korea
| | - Kwang-Hwan Jung
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul 04107, Republic of Korea.
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8
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Inoue K. Diversity, Mechanism, and Optogenetic Application of Light-Driven Ion Pump Rhodopsins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1293:89-126. [PMID: 33398809 DOI: 10.1007/978-981-15-8763-4_6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ion-transporting microbial rhodopsins are widely used as major molecular tools in optogenetics. They are categorized into light-gated ion channels and light-driven ion pumps. While the former passively transport various types of cations and anions in a light-dependent manner, light-driven ion pumps actively transport specific ions, such as H+, Na+, Cl-, against electrophysiological potential by using light energy. Since the ion transport by these pumps induces hyperpolarization of membrane potential and inhibit neural firing, light-driven ion-pumping rhodopsins are mostly applied as inhibitory optogenetics tools. Recent progress in genome and metagenome sequencing identified more than several thousands of ion-pumping rhodopsins from a wide variety of microbes, and functional characterization studies has been revealing many new types of light-driven ion pumps one after another. Since light-gated channels were reviewed in other chapters in this book, here the rapid progress in functional characterization, molecular mechanism study, and optogenetic application of ion-pumping rhodopsins were reviewed.
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Affiliation(s)
- Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, Chiba, Japan.
- PRESTO, Japan Science and Technology Agency, Saitama, Japan.
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9
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Friedrich D, Brünig FN, Nieuwkoop AJ, Netz RR, Hegemann P, Oschkinat H. Collective exchange processes reveal an active site proton cage in bacteriorhodopsin. Commun Biol 2020; 3:4. [PMID: 31925324 PMCID: PMC6941954 DOI: 10.1038/s42003-019-0733-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 12/02/2019] [Indexed: 01/01/2023] Open
Abstract
Proton translocation across membranes is vital to all kingdoms of life. Mechanistically, it relies on characteristic proton flows and modifications of hydrogen bonding patterns, termed protonation dynamics, which can be directly observed by fast magic angle spinning (MAS) NMR. Here, we demonstrate that reversible proton displacement in the active site of bacteriorhodopsin already takes place in its equilibrated dark-state, providing new information on the underlying hydrogen exchange processes. In particular, MAS NMR reveals proton exchange at D85 and the retinal Schiff base, suggesting a tautomeric equilibrium and thus partial ionization of D85. We provide evidence for a proton cage and detect a preformed proton path between D85 and the proton shuttle R82. The protons at D96 and D85 exchange with water, in line with ab initio molecular dynamics simulations. We propose that retinal isomerization makes the observed proton exchange processes irreversible and delivers a proton towards the extracellular release site. Daniel Friedrich et al. show that reversible proton translocation occurs in the dark–state of bacteriorhodopsin, involving the retinal Schiff base and D85 exchanging protons with H2O. They find evidence of an active site proton cage and possible proton transfer via R82.
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Affiliation(s)
- Daniel Friedrich
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany.,Freie Universität Berlin, Institut für Chemie und Biochemie, 14195, Berlin, Germany.,Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA.,Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, MA, 02215, USA
| | - Florian N Brünig
- Freie Universität Berlin, Fachbereich Physik, 14195, Berlin, Germany
| | - Andrew J Nieuwkoop
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany.,Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 123 Bevier Road, Piscataway, NJ, 08854, USA
| | - Roland R Netz
- Freie Universität Berlin, Fachbereich Physik, 14195, Berlin, Germany
| | - Peter Hegemann
- Humboldt-Universität zu Berlin, Institut für Biologie, Invalidenstr. 42, 10115, Berlin, Germany
| | - Hartmut Oschkinat
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany. .,Freie Universität Berlin, Institut für Chemie und Biochemie, 14195, Berlin, Germany.
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10
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Shibukawa A, Kojima K, Nakajima Y, Nishimura Y, Yoshizawa S, Sudo Y. Photochemical Characterization of a New Heliorhodopsin from the Gram-Negative Eubacterium Bellilinea caldifistulae (BcHeR) and Comparison with Heliorhodopsin-48C12. Biochemistry 2019; 58:2934-2943. [DOI: 10.1021/acs.biochem.9b00257] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Atsushi Shibukawa
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
| | - Keiichi Kojima
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
| | - Yu Nakajima
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba 277-8564, Japan
| | - Yosuke Nishimura
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba 277-8564, Japan
| | - Susumu Yoshizawa
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba 277-8564, Japan
- Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8563, Japan
| | - Yuki Sudo
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
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11
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Kaneko A, Inoue K, Kojima K, Kandori H, Sudo Y. Conversion of microbial rhodopsins: insights into functionally essential elements and rational protein engineering. Biophys Rev 2017; 9:861-876. [PMID: 29178082 DOI: 10.1007/s12551-017-0335-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 11/07/2017] [Indexed: 01/16/2023] Open
Abstract
Technological progress has enabled the successful application of functional conversion to a variety of biological molecules, such as nucleotides and proteins. Such studies have revealed the functionally essential elements of these engineered molecules, which are difficult to characterize at the level of an individual molecule. The functional conversion of biological molecules has also provided a strategy for their rational and atomistic design. The engineered molecules can be used in studies to improve our understanding of their biological functions and to develop protein-based tools. In this review, we introduce the functional conversion of membrane-embedded photoreceptive retinylidene proteins (also called rhodopsins) and discuss these proteins mainly on the basis of results obtained from our own studies. This information provides insights into the molecular mechanism of light-induced protein functions and their use in optogenetics, a technology which involves the use of light to control biological activities.
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Affiliation(s)
- Akimasa Kaneko
- Faculty of Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Keiichi Inoue
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama, 332-0012, Japan
| | - Keiichi Kojima
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama, 700-8530, Japan
| | - Hideki Kandori
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
| | - Yuki Sudo
- Faculty of Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan.
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama, 700-8530, Japan.
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12
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Hung CC, Chen XR, Ko YK, Kobayashi T, Yang CS, Yabushita A. Schiff Base Proton Acceptor Assists Photoisomerization of Retinal Chromophores in Bacteriorhodopsin. Biophys J 2017. [PMID: 28636908 DOI: 10.1016/j.bpj.2017.05.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
In this study, we investigated the ultrafast dynamics of bacteriorhodopsins (BRs) from Haloquadratum walsbyi (HwBR) and Haloarcula marismortui (HmBRI and HmBRII). First, the ultrafast dynamics were studied for three HwBR samples: wild-type, D93N mutation, and D104N mutation. The residues of the D93 and D104 mutants correspond to the control by the Schiff base proton acceptor and donor of the proton translocation subchannels. Measurements indicated that the negative charge from the Schiff base proton acceptor residue D93 interacts with the ultrafast and substantial change of the electrostatic potential associated with chromophore isomerization. By contrast, the Schiff base proton donor assists the restructuring of the chromophore cavity hydrogen-bond network during the thermalization of the vibrational hot state. Second, the ultrafast dynamics of the wild-types of HwBR, HmBRI, and HmBRII were compared. Measurements demonstrated that the hydrogen-bond network in the extracellular region in HwBR and HmBRII slows the photoisomerization of retinal chromophores, and the negatively charged helices on the cytoplasmic side of HwBR and HmBRII accelerate the thermalization of the vibrational hot state of retinal chromophores. The similarity of the correlation spectra of the wild-type HmBRI and D104N mutant of HwBR indicates that inactivation of the Schiff base proton donor induces a positive charge on the helices of the cytoplasmic side.
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Affiliation(s)
- Chih-Chang Hung
- Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan
| | - Xiao-Ru Chen
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Ying-Kuan Ko
- Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan
| | - Takayoshi Kobayashi
- Brain Science Inspired Life Support Research Center, The University of Electro-Communications, Tokyo, Japan; Research Center for Water Frontier Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Chii-Shen Yang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan.
| | - Atsushi Yabushita
- Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan; Faculty of Engineering, Kanagawa University, Yokohama, Japan.
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13
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Trieu MM, Devine EL, Lamarche LB, Ammerman AE, Greco JA, Birge RR, Theobald DL, Oprian DD. Expression, purification, and spectral tuning of RhoGC, a retinylidene/guanylyl cyclase fusion protein and optogenetics tool from the aquatic fungus Blastocladiella emersonii. J Biol Chem 2017; 292:10379-10389. [PMID: 28473465 DOI: 10.1074/jbc.m117.789636] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/03/2017] [Indexed: 02/03/2023] Open
Abstract
RhoGC is a rhodopsin (Rho)-guanylyl cyclase (GC) gene fusion molecule that is central to zoospore phototaxis in the aquatic fungus Blastocladiella emersonii It has generated considerable excitement because of its demonstrated potential as a tool for optogenetic manipulation of cell-signaling pathways involving cyclic nucleotides. However, a reliable method for expressing and purifying RhoGC is currently lacking. We present here an expression and purification system for isolation of the full-length RhoGC protein expressed in HEK293 cells in detergent solution. The protein exhibits robust light-dependent guanylyl cyclase activity, whereas a truncated form lacking the 17- to 20-kDa N-terminal domain is completely inactive under identical conditions. Moreover, we designed several RhoGC mutants to increase the utility of the protein for optogenetic studies. The first class we generated has altered absorption spectra designed for selective activation by different wavelengths of light. Two mutants were created with blue-shifted (E254D, λmax = 390 nm; D380N, λmax = 506 nm) and one with red-shifted (D380E, λmax = 533 nm) absorption maxima relative to the wild-type protein (λmax = 527 nm). We also engineered a double mutant, E497K/C566D, that changes the enzyme to a specific, light-stimulated adenylyl cyclase that catalyzes the formation of cAMP from ATP. We anticipate that this expression/purification system and these RhoGC mutants will facilitate mechanistic and structural exploration of this important enzyme.
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Affiliation(s)
- Melissa M Trieu
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Erin L Devine
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Lindsey B Lamarche
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Aaron E Ammerman
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Jordan A Greco
- the Departments of Chemistry and Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269
| | - Robert R Birge
- the Departments of Chemistry and Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269
| | - Douglas L Theobald
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Daniel D Oprian
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
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14
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Shigeta A, Ito S, Inoue K, Okitsu T, Wada A, Kandori H, Kawamura I. Solid-State Nuclear Magnetic Resonance Structural Study of the Retinal-Binding Pocket in Sodium Ion Pump Rhodopsin. Biochemistry 2017; 56:543-550. [PMID: 28040890 DOI: 10.1021/acs.biochem.6b00999] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The recently identified Krokinobacter rhodopsin 2 (KR2) functions as a light-driven sodium ion pump. The structure of the retinal-binding pocket of KR2 offers important insights into the mechanisms of KR2, which has motif of Asn112, Asp116, and Gln123 (NDQ) that is common among sodium ion pump rhodopsins but is unique among other microbial rhodopsins. Here we present solid-state nuclear magnetic resonance (NMR) characterization of retinal and functionally important residues in the vicinity of retinal in the ground state. We assigned chemical shifts of retinal C14 and C20 atoms, and Tyr218Cζ, Lys255Cε, and the protonated Schiff base of KR2 in lipid environments at acidic and neutral pH. 15N NMR signals of the protonated Schiff base showed a twist around the N-Cε bond under neutral conditions, compared with other microbial rhodopsins. These data indicated that the location of the counterion Asp116 is one helical pitch toward the cytoplasmic side. In acidic environments, the 15N Schiff base signal was shifted to a lower field, indicating that protonation of Asp116 induces reorientation during interactions between the Schiff base and Asp116. In addition, the Tyr218 residue in the vicinity of retinal formed a weak hydrogen bond with Asp251, a temporary Na+-binding site during the photocycle. These features may indicate unique mechanisms of sodium ion pumps.
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Affiliation(s)
- Arisu Shigeta
- Graduate School of Engineering, Yokohama National University , Hodogaya-ku, Yokohama 240-8501, Japan
| | - Shota Ito
- Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan
| | - Keiichi Inoue
- Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.,OptoBioTechnology Research Center, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.,PRESTO, Japan Science and Technology Agency (JST) , 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
| | - Takashi Okitsu
- Department of Organic Chemistry for Life Science, Kobe Pharmaceutical University , Higashinada-ku, Kobe 658-8558, Japan
| | - Akimori Wada
- Department of Organic Chemistry for Life Science, Kobe Pharmaceutical University , Higashinada-ku, Kobe 658-8558, Japan
| | - Hideki Kandori
- Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.,OptoBioTechnology Research Center, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan
| | - Izuru Kawamura
- Graduate School of Engineering, Yokohama National University , Hodogaya-ku, Yokohama 240-8501, Japan
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15
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Li D, Wang Y, Du H, Xu S, Li Z, Yang Y, Wang C. Nanoscale Electric Characteristics and Oriented Assembly of Halobacterium salinarum Membrane Revealed by Electric Force Microscopy. NANOMATERIALS 2016; 6:nano6110197. [PMID: 28335325 PMCID: PMC5245739 DOI: 10.3390/nano6110197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/28/2016] [Accepted: 10/08/2016] [Indexed: 11/25/2022]
Abstract
Purple membranes (PM) of the bacteria Halobacterium salinarum are a unique natural membrane where bacteriorhodopsin (BR) can convert photon energy and pump protons. Elucidating the electronic properties of biomembranes is critical for revealing biological mechanisms and developing new devices. We report here the electric properties of PMs studied by using multi-functional electric force microscopy (EFM) at the nanoscale. The topography, surface potential, and dielectric capacity of PMs were imaged and quantitatively measured in parallel. Two orientations of PMs were identified by EFM because of its high resolution in differentiating electrical characteristics. The extracellular (EC) sides were more negative than the cytoplasmic (CP) side by 8 mV. The direction of potential difference may facilitate movement of protons across the membrane and thus play important roles in proton pumping. Unlike the side-dependent surface potentials observed in PM, the EFM capacitive response was independent of the side and was measured to be at a dC/dz value of ~5.25 nF/m. Furthermore, by modification of PM with de novo peptides based on peptide-protein interaction, directional oriented PM assembly on silicon substrate was obtained for technical devices. This work develops a new method for studying membrane nanoelectronics and exploring the bioelectric application at the nanoscale.
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Affiliation(s)
- Denghua Li
- Agricultural Information Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Agricultural Information Service Technology of Ministry of Agriculture, Beijing 100081, China.
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
| | - Yibing Wang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
| | - Huiwen Du
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
| | - Shiwei Xu
- Agricultural Information Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Agricultural Information Service Technology of Ministry of Agriculture, Beijing 100081, China.
| | - Zhemin Li
- Agricultural Information Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Agricultural Information Service Technology of Ministry of Agriculture, Beijing 100081, China.
| | - Yanlian Yang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
| | - Chen Wang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
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16
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Li H, Govorunova EG, Sineshchekov OA, Spudich JL. Role of a helix B lysine residue in the photoactive site in channelrhodopsins. Biophys J 2014; 106:1607-17. [PMID: 24739160 DOI: 10.1016/j.bpj.2014.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 02/20/2014] [Accepted: 03/06/2014] [Indexed: 12/20/2022] Open
Abstract
In most studied microbial rhodopsins two conserved carboxylic acid residues (the homologs of Asp-85 and Asp-212 in bacteriorhodopsin) and an arginine residue (the homolog of Arg-82) form a complex counterion to the protonated retinylidene Schiff base, and neutralization of the negatively charged carboxylates causes red shifts of the absorption maximum. In contrast, the corresponding neutralizing mutations in some relatively low-efficiency channelrhodopsins (ChRs) result in blue shifts. These ChRs do not contain a lysine residue in the second helix, conserved in higher efficiency ChRs (Lys-132 in the crystallized ChR chimera). By action spectroscopy of photoinduced channel currents in HEK293 cells and absorption spectroscopy of detergent-purified pigments, we found that in tested ChRs the Lys-132 homolog controls the direction of spectral shifts in the mutants of the photoactive site carboxylic acid residues. Analysis of double mutants shows that red spectral shifts occur when this Lys is present, whether naturally or by mutagenesis, and blue shifts occur when it is replaced with a neutral residue. A neutralizing mutation of the Lys-132 homolog alone caused a red spectral shift in high-efficiency ChRs, whereas its introduction into low-efficiency ChR1 from Chlamydomonas augustae (CaChR1) caused a blue shift. Taking into account that the effective charge of the carboxylic acid residues is a key factor in microbial rhodopsin spectral tuning, these findings suggest that the Lys-132 homolog modulates their pKa values. On the other hand, mutation of the Arg-82 homolog that fulfills this role in bacteriorhodopsin caused minimal spectral changes in the tested ChRs. Titration revealed that the pKa of the Asp-85 homolog in CaChR1 lies in the alkaline region unlike in most studied microbial rhodopsins, but is substantially decreased by introduction of a Lys-132 homolog or neutralizing mutation of the Asp-212 homolog. In the three ChRs tested the Lys-132 homolog also alters channel current kinetics.
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Affiliation(s)
- Hai Li
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, Texas
| | - Elena G Govorunova
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, Texas
| | - Oleg A Sineshchekov
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, Texas
| | - John L Spudich
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, Texas.
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17
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Effects of Mutations of Lys41 and Asp102 of Bacteriorhodopsin. Biosci Biotechnol Biochem 2014; 75:1364-70. [DOI: 10.1271/bbb.110180] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Ranaghan MJ, Greco JA, Wagner NL, Grewal R, Rangarajan R, Koscielecki JF, Wise KJ, Birge RR. Photochromic bacteriorhodopsin mutant with high holographic efficiency and enhanced stability via a putative self-repair mechanism. ACS APPLIED MATERIALS & INTERFACES 2014; 6:2799-2808. [PMID: 24498928 PMCID: PMC3985900 DOI: 10.1021/am405363z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 02/05/2014] [Indexed: 06/03/2023]
Abstract
The Q photoproduct of bacteriorhodopsin (BR) is the basis of several biophotonic technologies that employ BR as the photoactive element. Several blue BR (bBR) mutants, generated by using directed evolution, were investigated with respect to the photochemical formation of the Q state. We report here a new bBR mutant, D85E/D96Q, which is capable of efficiently converting the entire sample to and from the Q photoproduct. At pH 8.5, where Q formation is optimal, the Q photoproduct requires 65 kJ mol(-1) of amber light irradiation (590 nm) for formation and 5 kJ mol(-1) of blue light (450 nm) for reversion, respectively. The melting temperature of the resting state and Q photoproduct, measured via differential scanning calorimetry, is observed at 100 °C and 89 °C at pH 8.5 or 91 °C and 82 °C at pH 9.5, respectively. We hypothesize that the protein stability of D85E/D96Q compared to other blue mutants is associated with a rapid equilibrium between the blue form E85(H) and the purple form E85(-) of the protein, the latter providing enhanced structural stability. Additionally, the protein is shown to be stable and functional when suspended in an acrylamide matrix at alkaline pH. Real-time photoconversion to and from the Q state is also demonstrated with the immobilized protein. Finally, the holographic efficiency of an ideal thin film using the Q state of D85E/D96Q is calculated to be 16.7%, which is significantly better than that provided by native BR (6-8%) and presents the highest efficiency of any BR mutant to date.
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Affiliation(s)
- Matthew J. Ranaghan
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Jordan A. Greco
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Nicole L. Wagner
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Rickinder Grewal
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Rekha Rangarajan
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Jeremy F. Koscielecki
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Kevin J. Wise
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Robert R. Birge
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, Connecticut 06269, United States
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
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19
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Lazarova T, Mlynarczyk K, Filipek S, Kolinski M, Wassenaar TA, Querol E, Renugopalakrishnan V, Viswanathan S, Padrós E. The effect of triple glutamic mutations E9Q/E194Q/E204Q on the structural stability of bacteriorhodopsin. FEBS J 2013; 281:1181-95. [PMID: 24341610 DOI: 10.1111/febs.12694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 11/21/2013] [Accepted: 12/12/2013] [Indexed: 10/25/2022]
Abstract
In the present study, we report on the structural features of the bacteriorhodopsin triple mutant E9Q/E194Q/E204Q (3Glu) of bacteriorhodopsin by combining experimental and molecular dynamics (MD) approaches. In 3Glu mutant, Glu9, Glu194 and Glu204 residues located at the extracellular side of the protein were mutated altogether to glutamines. UV-visible and differential scanning calorimetry experiments served as diagnostic tools for monitoring the resistance against thermal stress of the active site and the tertiary structures of the 3Glu. The analyses of the UV-visible thermal difference spectra demonstrate that the spectral forms at room temperature and the thermal unfolding path differ in the wild-type bacteriorhodopsin and the 3Glu. Even with these spectral differences, the thermal unfolding of the active site occurs at rather similar melting temperatures in both proteins. A noteworthy consequence of the mutations is the altered two-dimensional packing revealed by the lack of the pre-transition peak in differential scanning calorimetry traces of 3Glu mutant, as previously detected in wild-type and the corresponding single mutants. The infrared spectroscopy data agree with the loss of paracrystalinity, illustrating a substantial conversion of αII to αI helical conformation in the 3Glu mutant. Molecular dynamics simulations show higher dynamics flexibility of most of the extracellular regions of 3Glu, which may account for the somewhat lower tertiary structural stability of the mutated protein. Finally, hydrogen bond analysis reveals that the mutated Glu194 and Glu204 residues create ~ 50% less hydrogen bonds with water molecules compared to wild-type bacteriorhodopsin. These results exemplify the role of the water hydrogen-bonding network for structural integrity and conformational flexibility of bacteriorhodopsin.
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Affiliation(s)
- Tzvetana Lazarova
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Spain; Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, Spain
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20
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21
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Moltke S, Alexiev U, Heyn MP. Kinetics of Light-Induced Intramolecular Charge Transfer and Proton Release in Bacteriorhodopsin. Isr J Chem 2013. [DOI: 10.1002/ijch.199500039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Chou KC. A molecular piston mechanism of pumping protons by bacteriorhodopsin. Amino Acids 2013; 7:1-17. [PMID: 24185969 DOI: 10.1007/bf00808442] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1993] [Accepted: 12/20/1993] [Indexed: 10/26/2022]
Abstract
In this review the proton-pumping mechanism proposed recently for bacteriorhodopsin [Chou, K. C. (1993) Journal of Protein Chemistry, 12: 337-350] is illustrated in terms of a phenomenological model. According to the model, theβ-ionone of the retinal chromophore in bacteriorhodopsin can be phenomenologically imagined as a molecular "piston". The photon capture by bacteriorhodopsin would "pull" it up while the spontaneous decrease in potential energy would "push" it down so that it would be up and down alternately during the photocycle process. When it is pulled up, the gate of pore is open and the water channel for the proton translocation is through; when it is pushed down, the gate of pore is closed and the water channel is shut up. Such a model not only is quite consistent with experimental observations, but also provides useful insights and a different view to elucidate the protonpumping mechanism of bacteriorhodopsin. The essence of the model might be useful in investigating the mechanism of ion-channels of other membrane proteins.
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Affiliation(s)
- K C Chou
- Computational Chemistry, Upjohn Laboratories, 49001-4940, Kalamazoo, Michigan, USA
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23
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Claassens NJ, Volpers M, dos Santos VAPM, van der Oost J, de Vos WM. Potential of proton-pumping rhodopsins: engineering photosystems into microorganisms. Trends Biotechnol 2013; 31:633-42. [PMID: 24120288 DOI: 10.1016/j.tibtech.2013.08.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 08/19/2013] [Accepted: 08/27/2013] [Indexed: 01/04/2023]
Abstract
A wide range of proton-pumping rhodopsins (PPRs) have been discovered in recent years. Using a synthetic biology approach, PPR photosystems with different features can be easily introduced in nonphotosynthetic microbial hosts. PPRs can provide hosts with the ability to harvest light and drive the sustainable production of biochemicals or biofuels. PPRs use light energy to generate an outward proton flux, and the resulting proton motive force can subsequently power cellular processes. Recently, the introduction of PPRs in microbial production hosts has successfully led to light-driven biotechnological conversions. In this review, we discuss relevant features of natural PPRs, evaluate reported biotechnological applications of microbial production hosts equipped with PPRs, and provide an outlook on future developments.
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Affiliation(s)
- Nico J Claassens
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
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24
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Furutani Y, Kandori H. Hydrogen-bonding changes of internal water molecules upon the actions of microbial rhodopsins studied by FTIR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:598-605. [PMID: 24041645 DOI: 10.1016/j.bbabio.2013.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 09/04/2013] [Accepted: 09/06/2013] [Indexed: 11/27/2022]
Abstract
Microbial rhodopsins are classified into type-I rhodopsins, which utilize light energy to perform wide varieties of function, such as proton pumping, ion pumping, light sensing, cation channels, and so on. The crystal structures of several type-I rhodopsins were solved and the molecular mechanisms have been investigated based on the atomic structures. However, the crystal structures of proteins of interest are not always available and the basic architectures are sometimes quite similar, which obscures how the proteins achieve different functions. Stimulus-induced difference FTIR spectroscopy is a powerful tool to detect minute structural changes providing a clue for elucidating the molecular mechanisms. In this review, the studies on type-I rhodopsins from fungi and marine bacteria, whose crystal structures have not been solved yet, were summarized. Neurospora rhodopsin and Leptosphaeria rhodopsin found from Fungi have sequence similarity. The former has no proton pumping function, while the latter has. Proteorhodopsin is another example, whose proton pumping machinery is altered at alkaline and acidic conditions. We described how the structural changes of protein were different and how water molecules were involved in them. We reviewed the results on dynamics of the internal water molecules in pharaonis halorhodopsin as well. This article is part of a Special Issue entitled: Retinal Proteins - You can teach an old dog new tricks.
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Affiliation(s)
- Yuji Furutani
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan; Department of Structural Molecular Science, The Graduate University for Advanced Studies (SOKENDAI), 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan; PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
| | - Hideki Kandori
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
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25
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Grote M, Engelhard M, Hegemann P. Of ion pumps, sensors and channels - perspectives on microbial rhodopsins between science and history. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:533-45. [PMID: 23994288 DOI: 10.1016/j.bbabio.2013.08.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 08/20/2013] [Accepted: 08/22/2013] [Indexed: 10/26/2022]
Abstract
We present a historical overview of research on microbial rhodopsins ranging from the 1960s to the present date. Bacteriorhodopsin (BR), the first identified microbial rhodopsin, was discovered in the context of cell and membrane biology and shown to be an outward directed proton transporter. In the 1970s, BR had a big impact on membrane structural research and bioenergetics, that made it to a model for membrane proteins and established it as a probe for the introduction of various biophysical techniques that are widely used today. Halorhodopsin (HR), which supports BR physiologically by transporting negatively charged Cl⁻ into the cell, is researched within the microbial rhodopsin community since the late 1970s. A few years earlier, the observation of phototactic responses in halobacteria initiated research on what are known today as sensory rhodopsins (SR). The discovery of the light-driven ion channel, channelrhodopsin (ChR), serving as photoreceptors for behavioral responses in green alga has complemented inquiries into this photoreceptor family. Comparing the discovery stories, we show that these followed quite different patterns, albeit the objects of research being very similar. The stories of microbial rhodopsins present a comprehensive perspective on what can nowadays be considered one of nature's paradigms for interactions between organisms and light. Moreover, they illustrate the unfolding of this paradigm within the broader conceptual and instrumental framework of the molecular life sciences. This article is part of a Special Issue entitled: Retinal Proteins - You can teach an old dog new tricks.
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Affiliation(s)
- Mathias Grote
- Institut für Philosophie, Literatur-, Wissenschafts- und Technikgeschichte, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Martin Engelhard
- Max Planck Institut für Molekulare Physiologie, Otto Hahn Str. 11, 44227 Dortmund, Germany
| | - Peter Hegemann
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115 Berlin, Germany
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26
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Intramolecular proton transfer in channelrhodopsins. Biophys J 2013; 104:807-17. [PMID: 23442959 DOI: 10.1016/j.bpj.2013.01.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 12/19/2012] [Accepted: 01/02/2013] [Indexed: 10/27/2022] Open
Abstract
Channelrhodopsins serve as photoreceptors that control the motility behavior of green flagellate algae and act as light-gated ion channels when heterologously expressed in animal cells. Here, we report direct measurements of proton transfer from the retinylidene Schiff base in several channelrhodopsin variants expressed in HEK293 cells. A fast outward-directed current precedes the passive channel current that has the opposite direction at physiological holding potentials. This rapid charge movement occurs on the timescale of the M intermediate formation in microbial rhodopsins, including that for channelrhodopsin from Chlamydomonas augustae and its mutants, reported in this study. Mutant analysis showed that the glutamate residue corresponding to Asp(85) in bacteriorhodopsin acts as the primary acceptor of the Schiff-base proton in low-efficiency channelrhodopsins. Another photoactive-site residue corresponding to Asp(212) in bacteriorhodopsin serves as an alternative proton acceptor and plays a more important role in channel opening than the primary acceptor. In more efficient channelrhodopsins from Chlamydomonas reinhardtii, Mesostigma viride, and Platymonas (Tetraselmis) subcordiformis, the fast current was apparently absent. The inverse correlation of the outward proton transfer and channel activity is consistent with channel function evolving in channelrhodopsins at the expense of their capacity for active proton transport.
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27
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Wang T, Facciotti MT, Duan Y. Schiff base switch II precedes the retinal thermal isomerization in the photocycle of bacteriorhodopsin. PLoS One 2013; 8:e69882. [PMID: 23922839 PMCID: PMC3726731 DOI: 10.1371/journal.pone.0069882] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 06/13/2013] [Indexed: 11/21/2022] Open
Abstract
In bacteriorhodopsin, the order of molecular events that control the cytoplasmic or extracellular accessibility of the Schiff bases (SB) are not well understood. We use molecular dynamics simulations to study a process involved in the second accessibility switch of SB that occurs after its reprotonation in the N intermediate of the photocycle. We find that once protonated, the SB C15 = NZ bond switches from a cytoplasmic facing (13-cis, 15-anti) configuration to an extracellular facing (13-cis, 15-syn) configuration on the pico to nanosecond timescale. Significantly, rotation about the retinal’s C13 = C14 double bond is not observed. The dynamics of the isomeric state transitions of the protonated SB are strongly influenced by the surrounding charges and dielectric effects of other buried ions, particularly D96 and D212. Our simulations indicate that the thermal isomerization of retinal from 13-cis back to all-trans likely occurs independently from and after the SB C15 = NZ rotation in the N-to-O transition.
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Affiliation(s)
- Ting Wang
- UC Davis Genome Center, University of California Davis, Davis, California, United States of America
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States of America
| | - Marc T. Facciotti
- UC Davis Genome Center, University of California Davis, Davis, California, United States of America
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States of America
- * E-mail: (MF); (YD)
| | - Yong Duan
- UC Davis Genome Center, University of California Davis, Davis, California, United States of America
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States of America
- * E-mail: (MF); (YD)
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28
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Inoue K, Ono H, Abe-Yoshizumi R, Yoshizawa S, Ito H, Kogure K, Kandori H. A light-driven sodium ion pump in marine bacteria. Nat Commun 2013; 4:1678. [DOI: 10.1038/ncomms2689] [Citation(s) in RCA: 291] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 03/01/2013] [Indexed: 11/09/2022] Open
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29
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Hsu MF, Yu TF, Chou CC, Fu HY, Yang CS, Wang AHJ. Using Haloarcula marismortui bacteriorhodopsin as a fusion tag for enhancing and visible expression of integral membrane proteins in Escherichia coli. PLoS One 2013; 8:e56363. [PMID: 23457558 PMCID: PMC3574148 DOI: 10.1371/journal.pone.0056363] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 01/08/2013] [Indexed: 01/12/2023] Open
Abstract
Membrane proteins are key targets for pharmacological intervention because of their vital functions. Structural and functional studies of membrane proteins have been severely hampered because of the difficulties in producing sufficient quantities of properly folded and biologically active proteins. Here we generate a high-level expression system of integral membrane proteins in Escherichia coli by using a mutated bacteriorhodopsin (BR) from Haloarcula marismortui (HmBRI/D94N) as a fusion partner. A purification strategy was designed by incorporating a His-tag on the target membrane protein for affinity purification and an appropriate protease cleavage site to generate the final products. The fusion system can be used to detect the intended target membrane proteins during overexpression and purification either with the naked eye or by directly monitoring their characteristic optical absorption. In this study, we applied this approach to produce two functional integral membrane proteins, undecaprenyl pyrophosphate phosphatase and carnitine/butyrobetaine antiporter with significant yield enhancement. This technology could facilitate the development of a high-throughput strategy to screen for conditions that improve the yield of correctly folded target membrane proteins. Other robust BRs can also be incorporated in this system.
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Affiliation(s)
- Min-Feng Hsu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Core Facilities for Protein Structural Analysis, Academia Sinica, Taipei, Taiwan
| | - Tsung-Fu Yu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Chia-Cheng Chou
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Core Facilities for Protein Structural Analysis, Academia Sinica, Taipei, Taiwan
| | - Hsu-Yuan Fu
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Chii-Shen Yang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
- * E-mail: (CSY); (AHJW)
| | - Andrew H. J. Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Core Facilities for Protein Structural Analysis, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
- * E-mail: (CSY); (AHJW)
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30
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Saint Clair EC, Ogren JI, Mamaev S, Russano D, Kralj JM, Rothschild KJ. Near-IR resonance Raman spectroscopy of archaerhodopsin 3: effects of transmembrane potential. J Phys Chem B 2012. [PMID: 23189985 DOI: 10.1021/jp309996a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Archaerhodopsin 3 (AR3) is a light driven proton pump from Halorubrum sodomense that has been used as a genetically targetable neuronal silencer and an effective fluorescent sensor of transmembrane potential. Unlike the more extensively studied bacteriorhodopsin (BR) from Halobacterium salinarum, AR3 readily incorporates into the plasma membrane of both E. coli and mammalian cells. Here, we used near-IR resonance Raman confocal microscopy to study the effects of pH and membrane potential on the AR3 retinal chromophore structure. Measurements were performed both on AR3 reconstituted into E. coli polar lipids and in vivo in E. coli expressing AR3 in the absence and presence of a negative transmembrane potential. The retinal chromophore structure of AR3 is in an all-trans configuration almost identical to BR over the entire pH range from 3 to 11. Small changes are detected in the retinal ethylenic stretching frequency and Schiff Base (SB) hydrogen bonding strength relative to BR which may be related to a different water structure near the SB. In the case of the AR3 mutant D95N, at neutral pH an all-trans retinal O-like species (O(all-trans)) is found. At higher pH a second 13-cis retinal N-like species (N(13-cis)) is detected which is attributed to a slowly decaying intermediate in the red-light photocycle of D95N. However, the amount of N(13-cis) detected is less in E. coli cells but is restored upon addition of carbonyl cyanide m-chlorophenyl hydrazone (CCCP) or sonication, both of which dissipate the normal negative membrane potential. We postulate that these changes are due to the effect of membrane potential on the N(13-cis) to M(13-cis) levels accumulated in the D95N red-light photocycle and on a molecular level by the effects of the electric field on the protonation/deprotonation of the cytoplasmic accessible SB. This mechanism also provides a possible explanation for the observed fluorescence dependence of AR3 and other microbial rhodopsins on transmembrane potential.
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Affiliation(s)
- Erica C Saint Clair
- Department of Physics, Photonics Center and Molecular Biophysics Laboratory, Boston University, Boston, Massachusetts 02215, USA
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31
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Booth PJ. A successful change of circumstance: a transition state for membrane protein folding. Curr Opin Struct Biol 2012; 22:469-75. [DOI: 10.1016/j.sbi.2012.03.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 03/09/2012] [Accepted: 03/14/2012] [Indexed: 01/02/2023]
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32
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Herz J, Verhoefen MK, Weber I, Bamann C, Glaubitz C, Wachtveitl J. Critical role of Asp227 in the photocycle of proteorhodopsin. Biochemistry 2012; 51:5589-600. [PMID: 22738119 DOI: 10.1021/bi3003764] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photocycle of the proton acceptor complex mutant D227N of the bacterial retinal protein proteorhodopsin is investigated employing steady state pH-titration experiments in the UV-visible range as well as femtosecond-pump-probe spectroscopy and flash photolysis in the visible spectral range. The evaluation of the pH-dependent spectra showed that the neutralization of the charge at position 227 has a remarkable influence on the ground state properties of the protein. Both the pK(a) values of the primary proton acceptor and of the Schiff base are considerably decreased. Femtosecond-time-resolved measurements demonstrate that the general S(1) deactivation pathway; that is, the K-state formation is preserved in the D227N mutant. However, the pH-dependence of the reaction rate is lost by the substitution of Asp227 with an asparagine. Also no significant kinetic differences are observed upon deuteration. This is explained by the lack of a strongly hydrogen-bonded water in the vicinity of Asp97, Asp227, and the Schiff base or a change in the hydrogen bonding of it (Ikeda et al. (2007) Biochemistry 46, 5365-5373). The flash photolysis measurements prove a considerably elongated photocycle with pronounced pH-dependence. Interestingly, at pH 9 the M-state is visible until the end of the reaction cycle, leading to the conclusion that the mutation does not only lower the pK(a) of the Schiff base in the unphotolyzed ground state but also prevents an efficient reprotonation reaction.
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Affiliation(s)
- Julia Herz
- Institute of Physical and Theoretical Chemistry, Johann Wolfgang Goethe-University, Max von Laue-Strasse 7, 60438 Frankfurt am Main, Germany
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33
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Maiti TK, Yamada K, Inoue K, Kandori H. L105K Mutant of Proteorhodopsin. Biochemistry 2012; 51:3198-204. [DOI: 10.1021/bi201916a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tushar Kanti Maiti
- Department
of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555,
Japan
| | - Keisuke Yamada
- Department
of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555,
Japan
| | - Keiichi Inoue
- Department
of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555,
Japan
| | - Hideki Kandori
- Department
of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555,
Japan
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34
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Nack M, Radu I, Schultz BJ, Resler T, Schlesinger R, Bondar AN, del Val C, Abbruzzetti S, Viappiani C, Bamann C, Bamberg E, Heberle J. Kinetics of proton release and uptake by channelrhodopsin-2. FEBS Lett 2012; 586:1344-8. [PMID: 22504075 DOI: 10.1016/j.febslet.2012.03.047] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 03/23/2012] [Indexed: 11/28/2022]
Abstract
Electrophysiological experiments showed that the light-activated cation channel channelrhodopsin-2 (ChR2) pumps protons in the absence of a membrane potential. We determined here the kinetics of transient pH change using a water-soluble pH-indicator. It is shown that ChR2 released protons prior to uptake with a stoichiometry of 0.3 protons per ChR2. Comparison to the photocycle kinetics revealed that proton release and uptake match rise and decay of the P(3)(520) intermediate. As the P(3)(520) state also represents the conductive state of cation channeling, the concurrence of proton pumping and channel gating implies an intimate mechanistic link of the two functional modes. Studies on the E123T and S245E mutants show that these residues are not critically involved in proton translocation.
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Affiliation(s)
- Melanie Nack
- Freie Universität Berlin, Institute for Experimental Physics, Berlin, Germany
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35
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Yoshizawa S, Kawanabe A, Ito H, Kandori H, Kogure K. Diversity and functional analysis of proteorhodopsin in marine Flavobacteria. Environ Microbiol 2012; 14:1240-8. [DOI: 10.1111/j.1462-2920.2012.02702.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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36
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Chow BY, Han X, Boyden ES. Genetically encoded molecular tools for light-driven silencing of targeted neurons. PROGRESS IN BRAIN RESEARCH 2012; 196:49-61. [PMID: 22341320 PMCID: PMC3553588 DOI: 10.1016/b978-0-444-59426-6.00003-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ability to silence, in a temporally precise fashion, the electrical activity of specific neurons embedded within intact brain tissue, is important for understanding the role that those neurons play in behaviors, brain disorders, and neural computations. "Optogenetic" silencers, genetically encoded molecules that, when expressed in targeted cells within neural networks, enable their electrical activity to be quieted in response to pulses of light, are enabling these kinds of causal circuit analyses studies. Two major classes of optogenetic silencer are in broad use in species ranging from worm to monkey: light-driven inward chloride pumps, or halorhodopsins, and light-driven outward proton pumps, such as archaerhodopsins and fungal light-driven proton pumps. Both classes of molecule, when expressed in neurons via viral or other transgenic means, enable the targeted neurons to be hyperpolarized by light. We here review the current status of these sets of molecules, and discuss how they are being discovered and engineered. We also discuss their expression properties, ionic properties, spectral characteristics, and kinetics. Such tools may not only find many uses in the quieting of electrical activity for basic science studies but may also, in the future, find clinical uses for their ability to safely and transiently shut down cellular electrical activity in a precise fashion.
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Affiliation(s)
- Brian Y Chow
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
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37
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Kawanabe A, Furutani Y, Jung KH, Kandori H. An inward proton transport using Anabaena sensory rhodopsin. J Microbiol 2011; 49:1-6. [PMID: 21369972 DOI: 10.1007/s12275-011-0547-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Accepted: 01/14/2011] [Indexed: 11/24/2022]
Abstract
ATP is synthesized by an enzyme that utilizes proton motive force and thus nature creates various proton pumps. The best understood proton pump is bacteriorhodopsin (BR), an outward-directed light-driven proton pump in Halobacterium salinarum. Many archaeal and eubacterial rhodopsins are now known to show similar proton transport activity. Proton pumps must have a specific mechanism to exclude transport in the reverse direction to maintain a proton gradient, and in the case of BR, a highly hydrophobic cytoplasmic domain may constitute such machinery. Although an inward proton pump has neither been created naturally nor artificially, we recently reported that an inward-directed proton transport can be engineered from a bacterial rhodopsin by a single amino acid replacement Anabaena sensory rhodopsin (ASR) is a photochromic sensor in freshwater cyanobacteria, possessing little proton transport activity. When we replace Asp217 at the cytoplasmic domain (distance ∼ 15 Å from the retinal chromophore) to Glu, ASR is converted into an inward proton transport, driven by absorption of a single photon. FTIR spectra clearly show an increased proton affinity for Glu217, which presumably controls the unusual directionality opposite to normal proton pumps.
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Affiliation(s)
- Akira Kawanabe
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
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38
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Chow BY, Chuong AS, Klapoetke NC, Boyden ES. Synthetic physiology strategies for adapting tools from nature for genetically targeted control of fast biological processes. Methods Enzymol 2011; 497:425-43. [PMID: 21601097 DOI: 10.1016/b978-0-12-385075-1.00018-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The life and operation of cells involve many physiological processes that take place over fast timescales of milliseconds to minutes. Genetically encoded technologies for driving or suppressing specific fast physiological processes in intact cells, perhaps embedded within intact tissues in living organisms, are critical for the ability to understand how these physiological processes contribute to emergent cellular and organismal functions and behaviors. Such "synthetic physiology" tools are often incredibly complex molecular machines, in part because they must operate at high speeds, without causing side effects. We here explore how synthetic physiology molecules can be identified and deployed in cells, and how the physiology of these molecules in cellular contexts can be assessed and optimized. For concreteness, we discuss these methods in the context of the "optogenetic" light-gated ion channels and pumps that we have developed over the past few years as synthetic physiology tools and widely disseminated for use in neuroscience for probing the role of specific brain cell types in neural computations, behaviors, and pathologies. We anticipate that some of the insights revealed here may be of general value for the field of synthetic physiology, as they raise issues that will be of importance for the development and use of high-performance, high-speed, side-effect free physiological control tools in heterologous expression systems.
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Affiliation(s)
- Brian Y Chow
- Synthetic Neurobiology Group, The Media Laboratory and McGovern Institute, Departments of Biological Engineering and Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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39
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Song L, El-Sayed MA, Lanyi JK. Protein catalysis of the retinal subpicosecond photoisomerization in the primary process of bacteriorhodopsin photosynthesis. Science 2010; 261:891-4. [PMID: 17783735 DOI: 10.1126/science.261.5123.891] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The rate of retinal photoisomerization in wild-type bacteriorhodopsin (wt bR) is compared with that in a number of mutants in which a positively charged (Arg(82)), a negatively charged (Asp(85) or Asp(212)), or neutral hydrogen bonding (Asp(115) or Tyr(185)) amino acid residue known to be functionally important within the retinal cavity is replaced by a neutral, non-hydrogen bonding one. Only the replacements of the charged residues reduced the photoisomerization rate of the 13-cis and all-trans isomers present in these mutants by factors of approximately 1/4 and approximately 1/20, respectively. Retinal photo- and thermal isomerization catalysis and selectivity in wt bR by charged residues is discussed in terms of the known protein structure, the valence-bond wave functions of the ground and excited state of the retinal, and the electrostatic stabilization interactions within the retinal cavity.
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40
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Milder SJ. Correlation between absorption maxima and thermal isomerization rates in bacteriorhodopsin. Biophys J 2010; 60:440-6. [PMID: 19431800 DOI: 10.1016/s0006-3495(91)82070-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The reported rates of thermal 13-cis to all-trans isomerization of the protonated Schiff base of retinal (PSBR) in solution and in bacteriorhodopsin (BR) are shown to be correlated with the red shift in the absorption maximum of the chromophore, though the linear fit is different for BR and for a model PSBR in solution. Because the red shift in the absorption has been previously shown to be correlated with pi-electron delocalization in the chromophore, this suggests that the thermal isomerization rate is largely regulated by the amount of double bond character in the chromophore. Because the linear fit of isomerization rates with absorption maxima is different for BR and the model PSBR, specific interactions of the protein with the chromophore must also be a factor in determining thermal isomerization rates in BR. A model of the later steps in the photocycle of BR is presented in which the 13-cis to all-trans thermal isomerization occurs during the O intermediate.
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Affiliation(s)
- S J Milder
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973 USA
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41
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Yamada K, Kawanabe A, Kandori H. Importance of Alanine at Position 178 in Proteorhodopsin for Absorption of Prevalent Ambient Light in the Marine Environment. Biochemistry 2010; 49:2416-23. [DOI: 10.1021/bi9020204] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Keisuke Yamada
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Akira Kawanabe
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Hideki Kandori
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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42
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Kawanabe A, Furutani Y, Jung KH, Kandori H. Engineering an inward proton transport from a bacterial sensor rhodopsin. J Am Chem Soc 2010; 131:16439-44. [PMID: 19848403 DOI: 10.1021/ja904855g] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
ATP is synthesized by an enzyme that utilizes proton motive force, and thus, nature has created various proton pumps. The best-understood proton pump is bacteriorhodopsin (BR), an outward-directed, light-driven proton pump in Halobacterium salinarum. Many archaeal and eubacterial rhodopsins are now known to show similar proton transport activity. We previously converted BR into an inward-directed chloride ion pump, but an inward proton pump has never been created. Proton pumps must have a specific mechanism to exclude transport in the reverse direction in order to maintain a proton gradient, and in the case of BR, a highly hydrophobic cytoplasmic domain may constitute such machinery. Here we report that an inward-directed proton transport can be engineered from a bacterial rhodopsin by a single amino acid replacement. Anabaena sensory rhodopsin (ASR) is a photochromic sensor in freshwater cyanobacteria that possesses little proton pump activity. When we replaced Asp217 in the cytoplasmic domain (a distance of approximately 15 A from the retinal chromophore) by Glu, ASR exhibited an inward proton transport activity driven by absorption of a single photon. FTIR spectra clearly showed an increased proton affinity for Glu217, which presumably controls the unusual directionality opposite to that in normal proton pumps.
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Affiliation(s)
- Akira Kawanabe
- Department of Materials Science and Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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43
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Verhoefen MK, Lenz MO, Amarie S, Klare JP, Tittor J, Oesterhelt D, Engelhard M, Wachtveitl J. Primary Reaction of Sensory Rhodopsin II Mutant D75N and the Influence of Azide. Biochemistry 2009; 48:9677-83. [DOI: 10.1021/bi901197c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mirka-Kristin Verhoefen
- Institute of Physical and Theoretical Chemistry, Institute of Biophysics, Johann Wolfgang Goethe-University Frankfurt, Max von Laue-Strasse 7, 60438 Frankfurt am Main, Germany
| | - Martin O. Lenz
- Institute of Physical and Theoretical Chemistry, Institute of Biophysics, Johann Wolfgang Goethe-University Frankfurt, Max von Laue-Strasse 7, 60438 Frankfurt am Main, Germany
| | - Sergiu Amarie
- Institute of Physical and Theoretical Chemistry, Institute of Biophysics, Johann Wolfgang Goethe-University Frankfurt, Max von Laue-Strasse 7, 60438 Frankfurt am Main, Germany
| | - Johann P. Klare
- Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44139 Dortmund, Germany
| | - Jörg Tittor
- Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Dieter Oesterhelt
- Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Martin Engelhard
- Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44139 Dortmund, Germany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical Chemistry, Institute of Biophysics, Johann Wolfgang Goethe-University Frankfurt, Max von Laue-Strasse 7, 60438 Frankfurt am Main, Germany
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44
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Electron transfer processes in subunit I mutants of cytochrome bo quinol oxidase in Escherichia coli. Biosci Biotechnol Biochem 2009; 73:1599-603. [PMID: 19584547 DOI: 10.1271/bbb.90105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cytochrome bo is a terminal quinol oxidase in the aerobic respiratory chain of Escherichia coli. Subunit I binds all four redox centers, and electrons are transferred from quinols to high-spin heme o and Cu(B) through a bound uniquinone-8 and low-spin heme b. To explore the role of conserved charged amino acid residues, we examined the one-electron transfer processes in subunit I mutants. We found that all the mutants examined increased the electron transfer rate from the bound quinone to heme b more than 40-fold. Tyr288 and Lys362 are key residues in the K-channel for charge compensation of the heme o-Cu(B) binuclear center with protons. The Tyr288Phe and Lys362Gln mutants showed 100-fold decreases in heme b-to-heme o electron transfer, accompanied by large increases in the redox potential of heme o. Our results indicate that electromagnetic coupling of hemes is important for facilitated heme-heme electron transfer in cytochrome bo.
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45
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Yoshitsugu M, Yamada J, Kandori H. Color-changing mutation in the E-F loop of proteorhodopsin. Biochemistry 2009; 48:4324-30. [PMID: 19334675 DOI: 10.1021/bi900228a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is usually assumed that only amino acids located near the retinal chromophore are responsible for color tuning of rhodopsins. However, we recently found that replacement of Ala178 with Arg in the E-F loop of proteorhodopsin (PR), an archaeal-type rhodopsin in marine bacteria, shifts the lambda(max) from 525 to 545 nm at neutral pH [Yoshitsugu, M., Shibata, M., Ikeda, D., Furutani, Y., and Kandori, H. (2008) Angew. Chem., Int. Ed. 47, 3923-3926]. Since the location of Ala178 is distant from the retinal chromophore (approximately 25 A), the molecular mechanism of the unusual mutation effect on color tuning is intriguing. Here we studied this mechanism by using additional mutations and some analytical methods. Introduction of Arg into the corresponding amino acid in bacteriorhodopsin (BR, M163R mutant) does not change the absorption spectra, indicating that the effect is specific to PR. Introduction of Arg into the A-B or C-D loop yields little (3 nm) or no color change, respectively. T177R and P180R mutants exhibited absorption spectra identical to that of the wild type, while N176R and S179R mutants exhibit lambda(max) values of 528 and 535 nm, respectively. Therefore, the observed color change is position-specific, being fully effective at position 178 and half-effective at position 179. Salt affects the absorption spectra of wild-type and A178R PR similarly. FTIR spectroscopy at 77 K indicated similar chromophore structures for wild-type and A178R PR, and A178R PR pumps protons normally. We infer that the E-F loop has a unique structure in PR and the mutation of Ala178 disrupts the structure that includes the transmembrane region, leading to the observed changes in color and pK(a).
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Affiliation(s)
- Maiko Yoshitsugu
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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46
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Sugiyama Y, Wang H, Hikima T, Sato M, Kuroda J, Takahashi T, Ishizuka T, Yawo H. Photocurrent attenuation by a single polar-to-nonpolar point mutation of channelrhodopsin-2. Photochem Photobiol Sci 2009; 8:328-36. [DOI: 10.1039/b815762f] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Yoshitsugu M, Shibata M, Ikeda D, Furutani Y, Kandori H. Color change of proteorhodopsin by a single amino acid replacement at a distant cytoplasmic loop. Angew Chem Int Ed Engl 2008; 47:3923-6. [PMID: 18404767 DOI: 10.1002/anie.200705989] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Maiko Yoshitsugu
- Department of Materials Science and Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
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Borisov VB, Belevich I, Bloch DA, Mogi T, Verkhovsky MI. Glutamate 107 in Subunit I of Cytochrome bd from Escherichia coli Is Part of a Transmembrane Intraprotein Pathway Conducting Protons from the Cytoplasm to the Heme b595/Heme d Active Site. Biochemistry 2008; 47:7907-14. [DOI: 10.1021/bi800435a] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vitaliy B. Borisov
- Department of Molecular Energetics of Microorganisms, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russian Federation, Helsinki Bioenergetics Group, Institute of Biotechnology, University of Helsinki, PB 65 (Viikinkaari 1), 00014, Helsinki, Finland, and Department of Biomedical Chemistry, Graduate School of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ilya Belevich
- Department of Molecular Energetics of Microorganisms, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russian Federation, Helsinki Bioenergetics Group, Institute of Biotechnology, University of Helsinki, PB 65 (Viikinkaari 1), 00014, Helsinki, Finland, and Department of Biomedical Chemistry, Graduate School of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Dmitry A. Bloch
- Department of Molecular Energetics of Microorganisms, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russian Federation, Helsinki Bioenergetics Group, Institute of Biotechnology, University of Helsinki, PB 65 (Viikinkaari 1), 00014, Helsinki, Finland, and Department of Biomedical Chemistry, Graduate School of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tatsushi Mogi
- Department of Molecular Energetics of Microorganisms, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russian Federation, Helsinki Bioenergetics Group, Institute of Biotechnology, University of Helsinki, PB 65 (Viikinkaari 1), 00014, Helsinki, Finland, and Department of Biomedical Chemistry, Graduate School of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Michael I. Verkhovsky
- Department of Molecular Energetics of Microorganisms, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russian Federation, Helsinki Bioenergetics Group, Institute of Biotechnology, University of Helsinki, PB 65 (Viikinkaari 1), 00014, Helsinki, Finland, and Department of Biomedical Chemistry, Graduate School of Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Yoshitsugu M, Shibata M, Ikeda D, Furutani Y, Kandori H. Color Change of Proteorhodopsin by a Single Amino Acid Replacement at a Distant Cytoplasmic Loop. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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