1
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Pinto M, Saliminasab M, Harris A, Lazaratos M, Bondar AN, Ladizhansky V, Brown LS. The retinal chromophore environment in an inward light-driven proton pump studied by solid-state NMR and hydrogen-bond network analysis. Phys Chem Chem Phys 2024; 26:24090-24108. [PMID: 39248601 DOI: 10.1039/d4cp02611j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2024]
Abstract
Inward proton pumping is a relatively new function for microbial rhodopsins, retinal-binding light-driven membrane proteins. So far, it has been demonstrated for two unrelated subgroups of microbial rhodopsins, xenorhodopsins and schizorhodopsins. A number of recent studies suggest unique retinal-protein interactions as being responsible for the reversed direction of proton transport in the latter group. Here, we use solid-state NMR to analyze the retinal chromophore environment and configuration in an inward proton-pumping Antarctic schizorhodopsin. Using fully 13C-labeled retinal, we have assigned chemical shifts for every carbon atom and, assisted by structure modelling and molecular dynamics simulations, made a comparison with well-studied outward proton pumps, identifying locations of the unique protein-chromophore interactions for this functional subclass of microbial rhodopsins. Both the NMR results and molecular dynamics simulations point to the distinctive polar environment in the proximal part of the retinal, which may result in a hydration pattern dramatically different from that of the outward proton pumps, causing the reversed proton transport.
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Affiliation(s)
- Marie Pinto
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
| | - Maryam Saliminasab
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
| | - Andrew Harris
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
| | - Michalis Lazaratos
- Freie Universität Berlin, Physics Department, Theoretical Molecular Biophysics Group, D-14195 Berlin, Germany
| | - Ana-Nicoleta Bondar
- University of Bucharest, Faculty of Physics, Măgurele 077125, Romania
- Forschungszentrum Jülich, Institute for Computational Biomedicine (IAS-5/INM-9), 52428 Jülich, Germany
| | - Vladimir Ladizhansky
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
| | - Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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2
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Bertalan É, Konno M, Del Carmen Marín M, Bagherzadeh R, Nagata T, Brown L, Inoue K, Bondar AN. Hydrogen-Bonding and Hydrophobic Interaction Networks as Structural Determinants of Microbial Rhodopsin Function. J Phys Chem B 2024; 128:7407-7426. [PMID: 39024507 DOI: 10.1021/acs.jpcb.4c02946] [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: 07/20/2024]
Abstract
Microbial pump rhodopsins are highly versatile light-driven membrane proteins that couple protein conformational dynamics with ion translocation across the cell membranes. Understanding how microbial pump rhodopsins use specific amino acid residues at key functional sites to control ion selectivity and ion pumping direction is of general interest for membrane transporters, and could guide site-directed mutagenesis for optogenetics applications. To enable direct comparisons between proteins with different sequences we implement, for the first time, a unique numbering scheme for the microbial pump rhodopsin residues, NS-mrho. We use NS-mrho to show that distinct microbial pump rhodopsins typically have hydrogen-bond networks that are less conserved than anticipated from the amino acid residue conservation, whereas their hydrophobic interaction networks are largely conserved. To illustrate the role of the hydrogen-bond networks as structural elements that determine the functionality of microbial pump rhodopsins, we performed experiments, atomic-level simulations, and hydrogen bond network analyses on GR, the outward proton pump from Gloeobacter violaceus, and KR2, the outward sodium pump from Krokinobacter eikastus. The experiments indicate that multiple mutations that recover KR2 amino acid residues in GR not only fail to convert it into a sodium pump, but completely inactivate GR by abolishing photoisomerization of the retinal chromophore. This observation could be attributed to the drastically altered hydrogen-bond interaction network identified with simulations and network analyses. Taken together, our findings suggest that functional specificity could be encoded in the collective hydrogen-bond network of microbial pump rhodopsins.
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Affiliation(s)
- Éva Bertalan
- Department of Mathematics and Natural Sciences, RWTH Aachen University, Templergraben 59, 52062 Aachen, Germany
| | - Masae Konno
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwano-ha, Kashiwa 277-8581, Chiba, Japan
| | - María Del Carmen Marín
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwano-ha, Kashiwa 277-8581, Chiba, Japan
| | - Reza Bagherzadeh
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwano-ha, Kashiwa 277-8581, Chiba, Japan
| | - Takashi Nagata
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwano-ha, Kashiwa 277-8581, Chiba, Japan
| | - Leonid Brown
- Department of Physics, University of Guelph, 488 Gordon Street, Guelph, Ontario N1G 2W1, Canada
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwano-ha, Kashiwa 277-8581, Chiba, Japan
| | - Ana-Nicoleta Bondar
- Institute of Computational Biomedicine, Forschungszentrum Jülich, IAS-5/INM-9, Wilhelm-Johnen Straße, 5428 Jülich, Germany
- Faculty of Physics, University of Bucharest, Atomiştilor 405, 077125 Măgurele, Romania
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3
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Urui T, Shionoya T, Mizuno M, Inoue K, Kandori H, Mizutani Y. Chromophore-Protein Interactions Affecting the Polyene Twist and π-π* Energy Gap of the Retinal Chromophore in Schizorhodopsins. J Phys Chem B 2024; 128:2389-2397. [PMID: 38433395 DOI: 10.1021/acs.jpcb.3c08465] [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: 03/05/2024]
Abstract
The properties of a prosthetic group are broadened by interactions with its neighboring residues in proteins. The retinal chromophore in rhodopsins absorbs light, undergoes structural changes, and drives functionally important structural changes in proteins during the photocycle. It is therefore crucial to understand how chromophore-protein interactions regulate the molecular structure and electronic state of chromophores in rhodopsins. Schizorhodopsin is a newly discovered subfamily of rhodopsins found in the genomes of Asgard archaea, which are extant prokaryotes closest to the last common ancestor of eukaryotes and of other microbial species. Here, we report the effects of a hydrogen bond between a retinal Schiff base and its counterion on the twist of the polyene chain and the color of the retinal chromophore. Correlations between spectral features revealed the unexpected fact that the twist of the polyene chain is reduced as the hydrogen bond becomes stronger, suggesting that the twist is caused by tight atomic contacts between the chromophore and nearby residues. In addition, the strength of the hydrogen bond is the primary factor affecting the color-tuning of the retinal chromophore in schizorhodopsins. The findings of this study are valuable for manipulating the molecular structure and electronic state of the chromophore by controlling chromophore-protein interactions.
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Affiliation(s)
- Taito Urui
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Tomomi Shionoya
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Misao Mizuno
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Yasuhisa Mizutani
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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4
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Urui T, Hayashi K, Mizuno M, Inoue K, Kandori H, Mizutani Y. Cis- Trans Reisomerization Preceding Reprotonation of the Retinal Chromophore Is Common to the Schizorhodopsin Family: A Simple and Rational Mechanism for Inward Proton Pumping. J Phys Chem B 2024; 128:744-754. [PMID: 38204413 DOI: 10.1021/acs.jpcb.3c07510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The creation of unidirectional ion transporters across membranes represents one of the greatest challenges in chemistry. Proton-pumping rhodopsins are composed of seven transmembrane helices with a retinal chromophore bound to a lysine side chain via a Schiff base linkage and provide valuable insights for designing such transporters. What makes these transporters particularly intriguing is the discovery of both outward and inward proton-pumping rhodopsins. Surprisingly, despite sharing identical overall structures and membrane topologies, these proteins facilitate proton transport in opposite directions, implying an underlying rational mechanism that can transport protons in different directions within similar protein structures. In this study, we unraveled this mechanism by examining the chromophore structures of deprotonated intermediates in schizorhodopsins, a recently discovered subfamily of inward proton-pumping rhodopsins, using time-resolved resonance Raman spectroscopy. The photocycle of schizorhodopsins revealed the cis-trans thermal isomerization that precedes reprotonation at the Schiff base of the retinal chromophore. Notably, this order has not been observed in other proton-pumping rhodopsins, but here, it was observed in all seven schizorhodopsins studied across the archaeal domain, strongly suggesting that cis-trans thermal isomerization preceding reprotonation is a universal feature of the schizorhodopsin family. Based on these findings, we propose a structural basis for the remarkable order of events crucial for facilitating inward proton transport. The mechanism underlying inward proton transport by schizorhodopsins is straightforward and rational. The insights obtained from this study hold great promise for the design of transmembrane unidirectional ion transporters.
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Affiliation(s)
- Taito Urui
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Kouhei Hayashi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Misao Mizuno
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Yasuhisa Mizutani
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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5
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Schubert L, Chen JL, Fritz T, Marxer F, Langner P, Hoffmann K, Gamiz-Hernandez AP, Kaila VRI, Schlesinger R, Heberle J. Proton Release Reactions in the Inward H + Pump NsXeR. J Phys Chem B 2023; 127:8358-8369. [PMID: 37729557 DOI: 10.1021/acs.jpcb.3c04100] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Directional ion transport across biological membranes plays a central role in many cellular processes. Elucidating the molecular determinants for vectorial ion transport is key to understanding the functional mechanism of membrane-bound ion pumps. The extensive investigation of the light-driven proton pump bacteriorhodopsin from Halobacterium salinarum(HsBR) enabled a detailed description of outward proton transport. Although the structure of inward-directed proton pumping rhodopsins is very similar to HsBR, little is known about their protonation pathway, and hence, the molecular reasons for the vectoriality of proton translocation remain unclear. Here, we employ a combined experimental and theoretical approach to tracking protonation steps in the light-driven inward proton pump xenorhodopsin from Nanosalina sp. (NsXeR). Time-resolved infrared spectroscopy reveals the transient deprotonation of D220 concomitantly with deprotonation of the retinal Schiff base. Our molecular dynamics simulations support a proton release pathway from the retinal Schiff base via a hydrogen-bonded water wire leading to D220 that could provide a putative gating point for the proton release and with allosteric interactions to the retinal Schiff base. Our findings support the key role of D220 in mediating proton release to the cytoplasmic side and provide evidence that this residue is not the primary proton acceptor of the proton transiently released by the retinal Schiff base.
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Affiliation(s)
- Luiz Schubert
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195Berlin, Germany
| | - Jheng-Liang Chen
- Genetic Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195Berlin, Germany
| | - Tobias Fritz
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Florina Marxer
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195Berlin, Germany
| | - Pit Langner
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195Berlin, Germany
| | - Kirsten Hoffmann
- Genetic Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195Berlin, Germany
| | - Ana P Gamiz-Hernandez
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ramona Schlesinger
- Genetic Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195Berlin, Germany
| | - Joachim Heberle
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195Berlin, Germany
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6
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Saliminasab M, Yamazaki Y, Palmateer A, Harris A, Schubert L, Langner P, Heberle J, Bondar AN, Brown LS. A Proteorhodopsin-Related Photosensor Expands the Repertoire of Structural Motifs Employed by Sensory Rhodopsins. J Phys Chem B 2023; 127:7872-7886. [PMID: 37694950 PMCID: PMC10519204 DOI: 10.1021/acs.jpcb.3c04032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/09/2023] [Indexed: 09/12/2023]
Abstract
Microbial rhodopsins are light-activated retinal-binding membrane proteins that perform a variety of ion transport and photosensory functions. They display several cases of convergent evolution where the same function is present in unrelated or very distant protein groups. Here we report another possible case of such convergent evolution, describing the biophysical properties of a new group of sensory rhodopsins. The first representative of this group was identified in 2004 but none of the members had been expressed and characterized. The well-studied haloarchaeal sensory rhodopsins interacting with methyl-accepting Htr transducers are close relatives of the halobacterial proton pump bacteriorhodopsin. In contrast, the sensory rhodopsins we describe here are relatives of proteobacterial proton pumps, proteorhodopsins, but appear to interact with Htr-like transducers likewise, even though they do not conserve the residues important for the interaction of haloarchaeal sensory rhodopsins with their transducers. The new sensory rhodopsins display many unusual amino acid residues, including those around the retinal chromophore; most strikingly, a tyrosine in place of a carboxyl counterion of the retinal Schiff base on helix C. To characterize their unique sequence motifs, we augment the spectroscopy and biochemistry data by structural modeling of the wild-type and three mutants. Taken together, the experimental data, bioinformatics sequence analyses, and structural modeling suggest that the tyrosine/aspartate complex counterion contributes to a complex water-mediated hydrogen-bonding network that couples the protonated retinal Schiff base to an extracellular carboxylic dyad.
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Affiliation(s)
- Maryam Saliminasab
- Department
of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Yoichi Yamazaki
- Division
of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Alyssa Palmateer
- Department
of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Andrew Harris
- Department
of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Luiz Schubert
- Experimental
Molecular Biophysics Group, Department of Physics, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Pit Langner
- Experimental
Molecular Biophysics Group, Department of Physics, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Joachim Heberle
- Experimental
Molecular Biophysics Group, Department of Physics, Freie Universität Berlin, D-14195 Berlin, Germany
| | - Ana-Nicoleta Bondar
- University
of Bucharest, Faculty of Physics, Atomiştilor 405, Măgurele 077125, Romania
- Forschungszentrum
Jülich, Institute for Neuroscience and Medicine and Institute
for Advanced Simulations (IAS-5/INM-9), Computational Biomedicine, Wilhelm-Johnen Straße, 52428 Jülich, Germany
| | - Leonid S. Brown
- Department
of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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7
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Bondar AN, Barboiu M. Protons at bio-interfaces. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184139. [PMID: 36775006 DOI: 10.1016/j.bbamem.2023.184139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023]
Affiliation(s)
- Ana-Nicoleta Bondar
- University of Bucharest, Faculty of Physics, Atomiștilor 405, Măgurele 077125, Romania; Forschungszentrum Jülich, Institute of Computational Biomedicine, IAS-5/INM-9, Wilhelm-Johnen Straße, 5428 Jülich, Germany.
| | - Mihail Barboiu
- Université de Montpelier, Institut Europeen de Membranes, Adaptive Supramolecular Nanosystems Group, ENSCM-CNRS, Place E. Bataillon CC047, 34095 Motpellier, France.
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8
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Govorunova EG, Sineshchekov OA, Spudich JL. Potassium-selective channelrhodopsins. Biophys Physicobiol 2023; 20:e201011. [PMID: 38362336 PMCID: PMC10865875 DOI: 10.2142/biophysico.bppb-v20.s011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 02/03/2023] [Indexed: 02/05/2023] Open
Abstract
Since their discovery 21 years ago, channelrhodopsins have come of age and have become indispensable tools for optogenetic control of excitable cells such as neurons and myocytes. Potential therapeutic utility of channelrhodopsins has been proven by partial vision restoration in a human patient. Previously known channelrhodopsins are either proton channels, non-selective cation channels almost equally permeable to Na+ and K+ besides protons, or anion channels. Two years ago, we discovered a group of channelrhodopsins that exhibit over an order of magnitude higher selectivity for K+ than for Na+. These proteins, known as "kalium channelrhodopsins" or KCRs, lack the canonical tetrameric selectivity filter found in voltage- and ligand-gated K+ channels, and use a unique selectivity mechanism intrinsic to their individual protomers. Mutant analysis has revealed that the key residues responsible for K+ selectivity in KCRs are located at both ends of the putative cation conduction pathway, and their role has been confirmed by high-resolution KCR structures. Expression of KCRs in mouse neurons and human cardiomyocytes enabled optical inhibition of these cells' electrical activity. In this minireview we briefly discuss major results of KCR research obtained during the last two years and suggest some directions of future research.
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Affiliation(s)
- Elena G. Govorunova
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, USA
| | - Oleg A. Sineshchekov
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, USA
| | - John L. Spudich
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, USA
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9
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Kawasaki Y, Konno M, Inoue K. Kinetic study on the molecular mechanism of light-driven inward proton transport by schizorhodopsins. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:184016. [PMID: 35931184 DOI: 10.1016/j.bbamem.2022.184016] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/28/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Schizorhodopsins (SzRs) are light-driven inward proton pumping membrane proteins. A H+ is released to the cytoplasmic solvent from the chromophore, retinal Schiff base (RSB), after light absorption, and then another H+ is bound to the RSB at the end of photocyclic reaction. However, the mechanistic detail of H+ transfers in SzR is almost unknown. Here we studied the deuterium isotope effect and the temperature dependence of the reaction rate constants of elementary steps in the photocycles of SzRs. The former indicated that deprotonation and reprotonation of RSB is mainly accomplished by H+ hopping between heavy atoms with similar H+ affinity. Furthermore, the temperature dependence of the rate constants revealed that most of H+ transfer events have a high entropy barrier. In contrast, the activation enthalpy and entropy of extremely thermostable SzR (MsSzR) are significantly higher than other types of SzRs (SzR1 and MtSzR) suggesting that its highly thermostable structure is optimized with at the cost of slower reaction rates at ambient temperatures.
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Affiliation(s)
- Yuma Kawasaki
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Masae Konno
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan; PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
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10
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Hososhima S, Mizutori R, Abe-Yoshizumi R, Rozenberg A, Shigemura S, Pushkarev A, Konno M, Katayama K, Inoue K, Tsunoda SP, Béjà O, Kandori H. Proton-transporting heliorhodopsins from marine giant viruses. eLife 2022; 11:e78416. [PMID: 36065640 PMCID: PMC9448325 DOI: 10.7554/elife.78416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 08/07/2022] [Indexed: 12/02/2022] Open
Abstract
Rhodopsins convert light into signals and energy in animals and microbes. Heliorhodopsins (HeRs), a recently discovered new rhodopsin family, are widely present in archaea, bacteria, unicellular eukaryotes, and giant viruses, but their function remains unknown. Here, we report that a viral HeR from Emiliania huxleyi virus 202 (V2HeR3) is a light-activated proton transporter. V2HeR3 absorbs blue-green light, and the active intermediate contains the deprotonated retinal Schiff base. Site-directed mutagenesis study revealed that E191 in TM6 constitutes the gate together with the retinal Schiff base. E205 and E215 form a PAG of the Schiff base, and mutations at these positions converted the protein into an outward proton pump. Three environmental viral HeRs from the same group as well as a more distantly related HeR exhibited similar proton-transport activity, indicating that HeR functions might be diverse similarly to type-1 microbial rhodopsins. Some strains of E. huxleyi contain one HeR that is related to the viral HeRs, while its viruses EhV-201 and EhV-202 contain two and three HeRs, respectively. Except for V2HeR3 from EhV-202, none of these proteins exhibit ion transport activity. Thus, when expressed in the E. huxleyi cell membranes, only V2HeR3 has the potential to depolarize the host cells by light, possibly to overcome the host defense mechanisms or to prevent superinfection. The neuronal activity generated by V2HeR3 suggests that it can potentially be used as an optogenetic tool, similarly to type-1 microbial rhodopsins.
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Affiliation(s)
- Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyShowa-kuJapan
| | - Ritsu Mizutori
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyShowa-kuJapan
| | - Rei Abe-Yoshizumi
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyShowa-kuJapan
| | - Andrey Rozenberg
- Faculty of Biology, Technion-Israel Institute of TechnologyHaifaIsrael
| | - Shunta Shigemura
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyShowa-kuJapan
| | - Alina Pushkarev
- Faculty of Biology, Technion-Israel Institute of TechnologyHaifaIsrael
| | - Masae Konno
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyShowa-kuJapan
| | - Kota Katayama
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyShowa-kuJapan
- OptoBioTechnology Research Center, Nagoya Institute of TechnologyShowa-kuJapan
| | - Keiichi Inoue
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyShowa-kuJapan
| | - Satoshi P Tsunoda
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyShowa-kuJapan
- OptoBioTechnology Research Center, Nagoya Institute of TechnologyShowa-kuJapan
| | - Oded Béjà
- Faculty of Biology, Technion-Israel Institute of TechnologyHaifaIsrael
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyShowa-kuJapan
- OptoBioTechnology Research Center, Nagoya Institute of TechnologyShowa-kuJapan
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11
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Malakar P, Das I, Bhattacharya S, Harris A, Sheves M, Brown LS, Ruhman S. Bidirectional Photochemistry of Antarctic Microbial Rhodopsin: Emerging Trend of Ballistic Photoisomerization from the 13- cis Resting State. J Phys Chem Lett 2022; 13:8134-8140. [PMID: 36000820 PMCID: PMC9442786 DOI: 10.1021/acs.jpclett.2c01974] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
The decades-long ultrafast examination of nearly a dozen microbial retinal proteins, ion pumps, and sensory photoreceptors has not identified structure-function indicators which predict photoisomerization dynamics, whether it will be sub-picosecond and ballistic or drawn out with complex curve-crossing kinetics. Herein, we report the emergence of such an indicator. Using pH control over retinal isomer ratios, photoinduced transient absorption is recorded in an inward proton pumping Antarctic microbial rhodopsin (AntR) for 13-cis and all-trans retinal resting states. The all-trans fluorescent state decays with 1 ps exponential kinetics. In contrast, in 13-cis it decays within ∼300 fs accompanied by continuous spectral evolution, indicating ballistic internal conversion. The coherent wave packet nature of 13-cis isomerization in AntR matches published results for bacteriorhodopsin (BR) and Anabaena sensory rhodopsin (ASR), which also accommodate both all-trans and 13-cis retinal resting states, marking the emergence of a first structure-photodynamics indicator which holds for all three tested pigments.
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Affiliation(s)
- Partha Malakar
- Institute
of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Ishita Das
- Department
of Molecular Chemistry and Materials Science, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sudeshna Bhattacharya
- Department
of Molecular Chemistry and Materials Science, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Andrew Harris
- Department
of Physics, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Mordechai Sheves
- Department
of Molecular Chemistry and Materials Science, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Leonid S. Brown
- Department
of Physics, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Sanford Ruhman
- Institute
of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
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12
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Bondar AN. Graphs of Hydrogen-Bond Networks to Dissect Protein Conformational Dynamics. J Phys Chem B 2022; 126:3973-3984. [PMID: 35639610 DOI: 10.1021/acs.jpcb.2c00200] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Dynamic hydrogen bonds and hydrogen-bond networks are ubiquitous in proteins and protein complexes. Functional roles that have been assigned to hydrogen-bond networks include structural plasticity for protein function, allosteric conformational coupling, long-distance proton transfers, and transient storage of protons. Advances in structural biology provide invaluable insights into architectures of large proteins and protein complexes of direct interest to human physiology and disease, including G Protein Coupled Receptors (GPCRs) and the SARS-Covid-19 spike protein S, and give rise to the challenge of how to identify those interactions that are more likely to govern protein dynamics. This Perspective discusses applications of graph-based algorithms to dissect dynamical hydrogen-bond networks of protein complexes, with illustrations for GPCRs and spike protein S. H-bond graphs provide an overview of sites in GPCR structures where hydrogen-bond dynamics would be required to assemble longer-distance networks between functionally important motifs. In the case of spike protein S, graphs identify regions of the protein where hydrogen bonds rearrange during the reaction cycle and where local hydrogen-bond networks likely change in a virus variant of concern.
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Affiliation(s)
- Ana-Nicoleta Bondar
- University of Bucharest, Faculty of Physics, Str. Atomiştilor 405, 077125 Bucharest-Măgurele, Romania.,Institute for Neuroscience and Medicine and Institute for Advanced Simulations (IAS-5/INM-9), Computational Biomedicine, Forschungszentrum Jülich, 52425 Jülich, Germany
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13
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Brown LS. Light-driven proton transfers and proton transport by microbial rhodopsins - A biophysical perspective. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183867. [PMID: 35051382 DOI: 10.1016/j.bbamem.2022.183867] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/30/2021] [Accepted: 01/10/2022] [Indexed: 12/31/2022]
Abstract
In the last twenty years, our understanding of the rules and mechanisms for the outward light-driven proton transport (and underlying proton transfers) by microbial rhodopsins has been changing dramatically. It transitioned from a very detailed atomic-level understanding of proton transport by bacteriorhodopsin, the prototypical proton pump, to a confounding variety of sequence motifs, mechanisms, directions, and modes of transport in its newly found homologs. In this review, we will summarize and discuss experimental data obtained on new microbial rhodopsin variants, highlighting their contribution to the refinement and generalization of the ideas crystallized in the previous century. In particular, we will focus on the proton transport (and transfers) vectoriality and their structural determinants, which, in many cases, remain unidentified.
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Affiliation(s)
- Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Ontario N1G 2W1, Canada.
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14
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Karathanou K, Bondar AN. Algorithm to catalogue topologies of dynamic lipid hydrogen-bond networks. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183859. [PMID: 34999081 DOI: 10.1016/j.bbamem.2022.183859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/21/2021] [Accepted: 12/31/2021] [Indexed: 06/14/2023]
Abstract
Lipid membrane interfaces host reactions essential for the functioning of cells. The hydrogen-bonding environment at the membrane interface is particularly important for binding of proteins, drug molecules, and ions. We present here the implementation and applications of a depth-first search algorithm that analyzes dynamic lipid interaction networks. Lipid hydrogen-bond networks sampled transiently during simulations of lipid bilayers are clustered according to main types of topologies that characterize three-dimensional arrangements of lipids connected to each other via short water bridges. We characterize the dynamics of hydrogen-bonded lipid clusters in simulations of model POPE and POPE:POPG membranes that are often used for bacterial membrane proteins, in a model of the Escherichia coli membrane with six different lipid types, and in POPS membranes. We find that all lipids sample dynamic hydrogen-bonded networks with linear, star, or circular arrangements of the lipid headgroups, and larger networks with combinations of these three types of topologies. Overall, linear lipid-water bridges tend to be short. Water-mediated lipid clusters in all membranes with PE lipids tend to be somewhat small, with about four lipids in all membranes studied here. POPS membranes allow circular arrangements of three POPS lipids to be sampled frequently, and complex arrangements of linear, star, and circular paths may also be sampled. These findings suggest a molecular picture of the membrane interface whereby lipid molecules transiently connect in clusters with somewhat small spatial extension.
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Affiliation(s)
- Konstantina Karathanou
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany; University of Bucharest, Faculty of Physics, Str. Atomiştilor 405, Bucharest-Măgurele 077125, Romania; Institute for Neuroscience and Medicine and Institute for Advanced Simulations (IAS-5/INM-9), Computational Biomedicine, Forschungszentrum Jülich, 52425 Jülich, Germany.
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15
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Pedraza-González L, Barneschi L, Padula D, De Vico L, Olivucci M. Evolution of the Automatic Rhodopsin Modeling (ARM) Protocol. Top Curr Chem (Cham) 2022; 380:21. [PMID: 35291019 PMCID: PMC8924150 DOI: 10.1007/s41061-022-00374-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/29/2022] [Indexed: 10/27/2022]
Abstract
In recent years, photoactive proteins such as rhodopsins have become a common target for cutting-edge research in the field of optogenetics. Alongside wet-lab research, computational methods are also developing rapidly to provide the necessary tools to analyze and rationalize experimental results and, most of all, drive the design of novel systems. The Automatic Rhodopsin Modeling (ARM) protocol is focused on providing exactly the necessary computational tools to study rhodopsins, those being either natural or resulting from mutations. The code has evolved along the years to finally provide results that are reproducible by any user, accurate and reliable so as to replicate experimental trends. Furthermore, the code is efficient in terms of necessary computing resources and time, and scalable in terms of both number of concurrent calculations as well as features. In this review, we will show how the code underlying ARM achieved each of these properties.
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Affiliation(s)
- Laura Pedraza-González
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy. .,Department of Chemistry and Industrial Chemistry, University of Pisa, Via Moruzzi 13, 56124, Pisa, Italy.
| | - Leonardo Barneschi
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy
| | - Daniele Padula
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy
| | - Luca De Vico
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy.
| | - Massimo Olivucci
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy. .,Department of Chemistry, Bowling Green State University, Bowling Green, OH, 43403, USA.
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16
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Gordeliy V, Kovalev K, Bamberg E, Rodriguez-Valera F, Zinovev E, Zabelskii D, Alekseev A, Rosselli R, Gushchin I, Okhrimenko I. Microbial Rhodopsins. Methods Mol Biol 2022; 2501:1-52. [PMID: 35857221 DOI: 10.1007/978-1-0716-2329-9_1] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The first microbial rhodopsin, a light-driven proton pump bacteriorhodopsin from Halobacterium salinarum (HsBR), was discovered in 1971. Since then, this seven-α-helical protein, comprising a retinal molecule as a cofactor, became a major driver of groundbreaking developments in membrane protein research. However, until 1999 only a few archaeal rhodopsins, acting as light-driven proton and chloride pumps and also photosensors, were known. A new microbial rhodopsin era started in 2000 when the first bacterial rhodopsin, a proton pump, was discovered. Later it became clear that there are unexpectedly many rhodopsins, and they are present in all the domains of life and even in viruses. It turned out that they execute such a diversity of functions while being "nearly the same." The incredible evolution of the research area of rhodopsins and the scientific and technological potential of the proteins is described in the review with a focus on their function-structure relationships.
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Affiliation(s)
- Valentin Gordeliy
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France.
| | - Kirill Kovalev
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Institute of Crystallography, University of Aachen (RWTH), Aachen, Germany
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Francisco Rodriguez-Valera
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Alicante, Spain
| | - Egor Zinovev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Dmitrii Zabelskii
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Alexey Alekseev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Riccardo Rosselli
- Departamento de Fisiología, Genetica y Microbiología. Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | - Ivan Gushchin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Ivan Okhrimenko
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
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17
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Bertalan É, Lesca E, Schertler GFX, Bondar AN. C-Graphs Tool with Graphical User Interface to Dissect Conserved Hydrogen-Bond Networks: Applications to Visual Rhodopsins. J Chem Inf Model 2021; 61:5692-5707. [PMID: 34670076 DOI: 10.1021/acs.jcim.1c00827] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Dynamic hydrogen-bond networks provide proteins with structural plasticity required to translate signals such as ligand binding into a cellular response or to transport ions and larger solutes across membranes and, thus, are of central interest to understand protein reaction mechanisms. Here, we present C-Graphs, an efficient tool with graphical user interface that analyzes data sets of static protein structures or of independent numerical simulations to identify conserved, vs unique, hydrogen bonds and hydrogen-bond networks. For static structures, which may belong to the same protein or to proteins with different sequences, C-Graphs uses a clustering algorithm to identify sites of the hydrogen-bond network where waters are conserved among the structures. Using C-Graphs, we identify an internal protein-water hydrogen-bond network common to static structures of visual rhodopsins and adenosine A2A G protein-coupled receptors (GPCRs). Molecular dynamics simulations of a visual rhodopsin indicate that the conserved hydrogen-bond network from static structure can recruit dynamic hydrogen bonds and extend throughout most of the receptor. We release with this work the code for C-Graphs and its graphical user interface.
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Affiliation(s)
- Éva Bertalan
- Theoretical Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Elena Lesca
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, ETH Zürich, 5303 Villigen-PSI, Switzerland.,Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Gebhard F X Schertler
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, ETH Zürich, 5303 Villigen-PSI, Switzerland.,Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Ana-Nicoleta Bondar
- Theoretical Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.,Faculty of Physics, University of Bucharest, Strada Atomiştilor Nr. 405, Măgurele 077125, Romania.,Computational Biomedicine, IAS-5/INM-9, Institute for Neuroscience and Medicine and Institute for Advanced Simulations, Forschungszentrum Jülich, 52425 Jülich, Germany
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18
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Abstract
Rhodopsins are photoreceptive membrane proteins consisting of a common heptahelical transmembrane architecture that contains a retinal chromophore. Rhodopsin was first discovered in the animal retina in 1876, but a different type of rhodopsin, bacteriorhodopsin, was reported to be present in the cell membrane of an extreme halophilic archaeon, Halobacterium salinarum, 95 years later. Although these findings were made by physiological observation of pigmented tissue and cell bodies, recent progress in genomic and metagenomic analyses has revealed that there are more than 10,000 microbial rhodopsins and 9000 animal rhodopsins with large diversity and tremendous new functionality. In this Cell Science at a Glance article and accompanying poster, we provide an overview of the diversity of functions, structures, color discrimination mechanisms and optogenetic applications of these two rhodopsin families, and will also highlight the third distinctive rhodopsin family, heliorhodopsin.
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Affiliation(s)
- Takashi Nagata
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.,PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
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19
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20
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Abstract
Microbial rhodopsins are diverse photoreceptive proteins containing a retinal chromophore and are found in all domains of cellular life and are even encoded in genomes of viruses. These rhodopsins make up two families: type 1 rhodopsins and the recently discovered heliorhodopsins. These families have seven transmembrane helices with similar structures but opposing membrane orientation. Microbial rhodopsins participate in a portfolio of light-driven energy and sensory transduction processes. In this review we present data collected over the last two decades about these rhodopsins and describe their diversity, functions, and biological and ecological roles. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Andrey Rozenberg
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel; ,
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan;
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya 466-8555, Japan;
| | - Oded Béjà
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel; ,
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21
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Siemers M, Bondar AN. Interactive Interface for Graph-Based Analyses of Dynamic H-Bond Networks: Application to Spike Protein S. J Chem Inf Model 2021; 61:2998-3014. [PMID: 34133162 DOI: 10.1021/acs.jcim.1c00306] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Dynamic hydrogen-bond networks are key determinants of protein conformational dynamics. In the case of macromolecular protein complexes, which can have a large number of hydrogen bonds giving rise to extensive hydrogen-bond networks, efficient algorithms are required to analyze interactions that could be important for the dynamics and biological function of the complex. We present here a highly efficient, standalone interface designed for analyses of dynamical hydrogen-bond networks of biomolecules and macromolecular complexes. To facilitate a comprehensive description of protein dynamics, the interface includes analyses of hydrophobic interactions. We illustrate the usefulness and workflow of the interface by dissecting the dynamics of the ectodomain of SARS-CoV-2 protein S in its closed conformation. We find that protein S contains numerous local clusters of dynamic hydrogen bonds and identify hydrogen bonds that are sampled persistently. The receptor binding domain of the spike protein hosts only a handful of persistent hydrogen-bond clusters, suggesting structural plasticity. Our data analysis interface is released here for open use.
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Affiliation(s)
- Malte Siemers
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
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22
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23
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Abstract
Schizorhodopsins (SzRs), a new rhodopsin family identified in Asgard archaea, are phylogenetically located at an intermediate position between type-1 microbial rhodopsins and heliorhodopsins. SzRs work as light-driven inward H+ pumps as xenorhodopsins in bacteria. Although E81 plays an essential role in inward H+ release, the H+ is not metastably trapped in such a putative H+ acceptor, unlike the other H+ pumps. It remains elusive why SzR exhibits different kinetic behaviors in H+ release. Here, we report the crystal structure of SzR AM_5_00977 at 2.1 Å resolution. The SzR structure superimposes well on that of bacteriorhodopsin rather than heliorhodopsin, suggesting that SzRs are classified with type-1 rhodopsins. The structure-based mutagenesis study demonstrated that the residues N100 and V103 around the β-ionone ring are essential for color tuning in SzRs. The cytoplasmic parts of transmembrane helices 2, 6, and 7 are shorter than those in the other microbial rhodopsins, and thus E81 is located near the cytosol and easily exposed to the solvent by light-induced structural change. We propose a model of untrapped inward H+ release; H+ is released through the water-mediated transport network from the retinal Schiff base to the cytosol by the side of E81. Moreover, most residues on the H+ transport pathway are not conserved between SzRs and xenorhodopsins, suggesting that they have entirely different inward H+ release mechanisms.
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24
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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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25
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Bertalan É, Lešnik S, Bren U, Bondar AN. Protein-water hydrogen-bond networks of G protein-coupled receptors: Graph-based analyses of static structures and molecular dynamics. J Struct Biol 2020; 212:107634. [DOI: 10.1016/j.jsb.2020.107634] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 09/06/2020] [Accepted: 09/24/2020] [Indexed: 12/15/2022]
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26
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Lokiarchaeota archaeon schizorhodopsin-2 (LaSzR2) is an inward proton pump displaying a characteristic feature of acid-induced spectral blue-shift. Sci Rep 2020; 10:20857. [PMID: 33257762 PMCID: PMC7704677 DOI: 10.1038/s41598-020-77936-9] [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: 04/06/2020] [Accepted: 10/29/2020] [Indexed: 11/25/2022] Open
Abstract
The photoreactive protein rhodopsin is widespread in microorganisms and has a variety of photobiological functions. Recently, a novel phylogenetically distinctive group named ‘schizorhodopsin (SzR)’ has been identified as an inward proton pump. We performed functional and spectroscopic studies on an uncharacterised schizorhodopsin from the phylum Lokiarchaeota archaeon. The protein, LaSzR2, having an all-trans-retinal chromophore, showed inward proton pump activity with an absorption maximum at 549 nm. The pH titration experiments revealed that the protonated Schiff base of the retinal chromophore (Lys188, pKa = 12.3) is stabilised by the deprotonated counterion (presumably Asp184, pKa = 3.7). The flash-photolysis experiments revealed the presence of two photointermediates, K and M. A proton was released and uptaken from bulk solution upon the formation and decay of the M intermediate. During the M-decay, the Schiff base was reprotonated by the proton from a proton donating residue (presumably Asp172). These properties were compared with other inward (SzRs and xenorhodopsins, XeRs) and outward proton pumps. Notably, LaSzR2 showed acid-induced spectral ‘blue-shift’ due to the protonation of the counterion, whereas outward proton pumps showed opposite shifts (red-shifts). Thus, we can distinguish between inward and outward proton pumps by the direction of the acid-induced spectral shift.
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27
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Karathanou K, Lazaratos M, Bertalan É, Siemers M, Buzar K, Schertler GFX, Del Val C, Bondar AN. A graph-based approach identifies dynamic H-bond communication networks in spike protein S of SARS-CoV-2. J Struct Biol 2020; 212:107617. [PMID: 32919067 PMCID: PMC7481144 DOI: 10.1016/j.jsb.2020.107617] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 09/03/2020] [Accepted: 09/06/2020] [Indexed: 02/07/2023]
Abstract
Corona virus spike protein S is a large homo-trimeric protein anchored in the membrane of the virion particle. Protein S binds to angiotensin-converting-enzyme 2, ACE2, of the host cell, followed by proteolysis of the spike protein, drastic protein conformational change with exposure of the fusion peptide of the virus, and entry of the virion into the host cell. The structural elements that govern conformational plasticity of the spike protein are largely unknown. Here, we present a methodology that relies upon graph and centrality analyses, augmented by bioinformatics, to identify and characterize large H-bond clusters in protein structures. We apply this methodology to protein S ectodomain and find that, in the closed conformation, the three protomers of protein S bring the same contribution to an extensive central network of H-bonds, and contribute symmetrically to a relatively large H-bond cluster at the receptor binding domain, and to a cluster near a protease cleavage site. Markedly different H-bonding at these three clusters in open and pre-fusion conformations suggest dynamic H-bond clusters could facilitate structural plasticity and selection of a protein S protomer for binding to the host receptor, and proteolytic cleavage. From analyses of spike protein sequences we identify patches of histidine and carboxylate groups that could be involved in transient proton binding.
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Affiliation(s)
- Konstantina Karathanou
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Michalis Lazaratos
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Éva Bertalan
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Malte Siemers
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Krzysztof Buzar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Gebhard F X Schertler
- Paul Scherrer Institut, Department of Biology and Chemistry, Laboratory of Biomolecular Research, CH-5303 Villigen-PSI, Switzerland; ETH Zürich, Department of Biology, 8093 Zürich, Switzerland
| | - Coral Del Val
- University of Granada, Department of Computer Science and Artificial Intelligence, E-18071 Granada, Spain; Instituto de Investigación Biosanitaria ibs.GRANADA, 18012 Granada, Spain; Andalusian Research Institute in Data Science and Computational Intelligence (DaSCI Institute), 18014 Granada, Spain
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany.
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His57 controls the efficiency of ESR, a light-driven proton pump from Exiguobacterium sibiricum at low and high pH. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148328. [PMID: 33075275 DOI: 10.1016/j.bbabio.2020.148328] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/06/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022]
Abstract
ESR, a light-driven proton pump from Exiguobacterium sibiricum, contains a lysine residue (Lys96) in the proton donor site. Substitution of Lys96 with a nonionizable residue greatly slows reprotonation of the retinal Schiff base. The recent study of electrogenicity of the K96A mutant revealed that overall efficiency of proton transport is decreased in the mutant due to back reactions (Siletsky et al., BBA, 2019). Similar to members of the proteorhodopsin and xanthorhodopsin families, in ESR the primary proton acceptor from the Schiff base, Asp85, closely interacts with His57. To examine the role of His57 in the efficiency of proton translocation by ESR, we studied the effects of H57N and H57N/K96A mutations on the pH dependence of light-induced pH changes in suspensions of Escherichia coli cells, kinetics of absorption changes and electrogenic proton transfer reactions during the photocycle. We found that at low pH (<5) the proton pumping efficiency of the H57N mutant in E. coli cells and its electrogenic efficiency in proteoliposomes is substantially higher than in the WT, suggesting that interaction of His57 with Asp85 sets the low pH limit for H+ pumping in ESR. The electrogenic components that correspond to proton uptake were strongly accelerated at low pH in the mutant indicating that Lys96 functions as a very efficient proton donor at low pH. In the H57N/K96A mutant, a higher H+ pumping efficiency compared with K96A was observed especially at high pH, apparently from eliminating back reactions between Asp85 and the Schiff base by the H57N mutation.
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RubyACRs, nonalgal anion channelrhodopsins with highly red-shifted absorption. Proc Natl Acad Sci U S A 2020; 117:22833-22840. [PMID: 32873643 DOI: 10.1073/pnas.2005981117] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Channelrhodopsins are light-gated ion channels widely used to control neuronal firing with light (optogenetics). We report two previously unknown families of anion channelrhodopsins (ACRs), one from the heterotrophic protists labyrinthulea and the other from haptophyte algae. Four closely related labyrinthulea ACRs, named RubyACRs here, exhibit a unique retinal-binding pocket that creates spectral sensitivities with maxima at 590 to 610 nm, the most red-shifted channelrhodopsins known, long-sought for optogenetics, and more broadly the most red-shifted microbial rhodopsins thus far reported. We identified three spectral tuning residues critical for the red-shifted absorption. Photocurrents recorded from the RubyACR from Aurantiochytrium limacinum (designated AlACR1) under single-turnover excitation exhibited biphasic decay, the rate of which was only weakly voltage dependent, in contrast to that in previously characterized cryptophyte ACRs, indicating differences in channel gating mechanisms between the two ACR families. Moreover, in A. limacinum we identified three ACRs with absorption maxima at 485, 545, and 590 nm, indicating color-sensitive photosensing with blue, green, and red spectral variation of ACRs within individual species of the labyrinthulea family. We also report functional energy transfer from a cytoplasmic fluorescent protein domain to the retinal chromophore bound within RubyACRs.
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