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Nishikino T, Sugimoto T, Kandori H. Low-temperature FTIR spectroscopy of the L/Q switch of proteorhodopsin. Phys Chem Chem Phys 2024; 26:22959-22967. [PMID: 39171479 DOI: 10.1039/d4cp02248c] [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: 08/23/2024]
Abstract
Rhodopsins are photoreceptive membrane proteins containing a retinal chromophore, and the color tuning mechanism in rhodopsins is one of the important topics. Color switch is a color-determining residue at the same position, where replacement of red- and blue-shifting amino acids in two wild-type rhodopsins causes spectral blue- and red-shifts, respectively. The first and most famous color switch in microbial rhodopsins is the L/Q switch in proteorhodopsins (PRs). Green- or blue-absorbing PR (GPR or BPR) contains Leu and Gln at position 105 of the C-helix (TM3), respectively, and their replacement converted absorbing colors. The L/Q switch enables bacteria to absorb green or blue light in shallow or deep ocean waters, respectively. Although Gln and Leu are hydrophilic and hydrophobic residues, respectively, a comprehensive mutation study of position 105 in GPR revealed that the λmax correlated with the volume of residues, not the hydropathy index. To gain structural insights into the mechanism, we applied low-temperature FTIR spectroscopy of L105Q GPR, and the obtained spectra were compared with those of GPR and BPR. The difference FTIR spectra of L105Q GPR were similar to those of BPR, not GPR, implying that the L/Q switch converts the GPR structure into a BPR structure in terms of the local environments of the retinal chromophore. It includes retinal skeletal vibration, hydrogen-bonding strength of the protonated Schiff base, amide-A vibration (peptide backbone), and protein-bound water molecules. Consequently color is switched accompanying such structural alterations, and known as the L/Q switch.
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Affiliation(s)
- Tatsuro Nishikino
- 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
| | - Teppei Sugimoto
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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2
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Fujimoto KJ, Minowa F, Nishina M, Nakamura S, Ohashi S, Katayama K, Kandori H, Yanai T. Molecular Mechanism of Spectral Tuning by Chloride Binding in Monkey Green Sensitive Visual Pigment. J Phys Chem Lett 2023; 14:1784-1793. [PMID: 36762971 DOI: 10.1021/acs.jpclett.2c03619] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The visual pigments of the cones perceive red, green, and blue colors. The monkey green (MG) pigment possesses a unique Cl- binding site; however, its relationship to the spectral tuning in green pigments remains elusive. Recently, FTIR spectroscopy revealed the characteristic structural modifications of the retinal binding site by Cl- binding. Herein, we report the computational structural modeling of MG pigments and quantum-chemical simulation to investigate its spectral redshift and physicochemical relevance when Cl- is present. Our protein structures reflect the previously suggested structural changes. AlphaFold2 failed to predict these structural changes. Excited-state calculations successfully reproduced the experimental red-shifted absorption energies, corroborating our protein structures. Electrostatic energy decomposition revealed that the redshift results from the His197 protonation state and conformations of Glu129, Ser202, and Ala308; however, Cl- itself contributes to the blueshift. Site-directed mutagenesis supported our analysis. These modeled structures may provide a valuable foundation for studying cone pigments.
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Affiliation(s)
- Kazuhiro J Fujimoto
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furocho, Chikusa, Nagoya 464-8601, Japan
- Department of Chemistry, Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya, 464-8601, Japan
| | - Fumika Minowa
- Department of Chemistry, Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya, 464-8601, Japan
| | - Michiya Nishina
- Department of Chemistry, Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya, 464-8601, Japan
| | - Shunta Nakamura
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
| | - Sayaka Ohashi
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
| | - Kota Katayama
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
| | - Takeshi Yanai
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furocho, Chikusa, Nagoya 464-8601, Japan
- Department of Chemistry, Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya, 464-8601, Japan
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3
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Scholz L, Neugebauer J. Protein Response Effects on Cofactor Excitation Energies from First Principles: Augmenting Subsystem Time-Dependent Density-Functional Theory with Many-Body Expansion Techniques. J Chem Theory Comput 2021; 17:6105-6121. [PMID: 34524815 DOI: 10.1021/acs.jctc.1c00551] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We investigate the possibility of describing protein response effects on a chromophore excitation by means of subsystem time-dependent density-functional theory (sTDDFT) in combination with a many-body expansion (MBE) approach. While sTDDFT is in principle intrinsically able to include such contributions, addressing cofactor excitations in protein models or entire proteins with full environment-response treatments is currently out of reach. Taking different model structures of the green fluorescent protein (GFP) and bovine rhodopsin as examples, we demonstrate that an embedded-MBE approach based on sTDDFT in its simplest version leads to a good agreement of the predicted protein response effect already at second order. To reproduce reference response effects from nonsubsystem TDDFT calculations quantitatively (error ≤ 5%), however, a third- or even fourth-order MBE may be required. For the latter case, we explore a selective inclusion of fourth-order terms that drastically reduces the computational burden. In addition, we demonstrate how this sTDDFT-MBE treatment can be utilized as an analysis tool to identify residues with dominant response contributions. This, in turn, can be employed to arrive at smaller structural models for light-absorbing proteins, which still feature all of the main characteristics in terms of photoresponse properties.
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Affiliation(s)
- Linus Scholz
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Johannes Neugebauer
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
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4
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Fujimoto KJ. Electronic Couplings and Electrostatic Interactions Behind the Light Absorption of Retinal Proteins. Front Mol Biosci 2021; 8:752700. [PMID: 34604313 PMCID: PMC8480471 DOI: 10.3389/fmolb.2021.752700] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
The photo-functional chromophore retinal exhibits a wide variety of optical absorption properties depending on its intermolecular interactions with surrounding proteins and other chromophores. By utilizing these properties, microbial and animal rhodopsins express biological functions such as ion-transport and signal transduction. In this review, we present the molecular mechanisms underlying light absorption in rhodopsins, as revealed by quantum chemical calculations. Here, symmetry-adapted cluster-configuration interaction (SAC-CI), combined quantum mechanical and molecular mechanical (QM/MM), and transition-density-fragment interaction (TDFI) methods are used to describe the electronic structure of the retinal, the surrounding protein environment, and the electronic coupling between chromophores, respectively. These computational approaches provide successful reproductions of experimentally observed absorption and circular dichroism (CD) spectra, as well as insights into the mechanisms of unique optical properties in terms of chromophore-protein electrostatic interactions and chromophore-chromophore electronic couplings. On the basis of the molecular mechanisms revealed in these studies, we also discuss strategies for artificial design of the optical absorption properties of rhodopsins.
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Affiliation(s)
- Kazuhiro J Fujimoto
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Japan.,Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan
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5
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Broser M, Spreen A, Konold PE, Schiewer E, Adam S, Borin V, Schapiro I, Seifert R, Kennis JTM, Bernal Sierra YA, Hegemann P. NeoR, a near-infrared absorbing rhodopsin. Nat Commun 2020; 11:5682. [PMID: 33173168 PMCID: PMC7655827 DOI: 10.1038/s41467-020-19375-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 10/06/2020] [Indexed: 12/18/2022] Open
Abstract
The Rhizoclosmatium globosum genome encodes three rhodopsin-guanylyl cyclases (RGCs), which are predicted to facilitate visual orientation of the fungal zoospores. Here, we show that RGC1 and RGC2 function as light-activated cyclases only upon heterodimerization with RGC3 (NeoR). RGC1/2 utilize conventional green or blue-light-sensitive rhodopsins (λmax = 550 and 480 nm, respectively), with short-lived signaling states, responsible for light-activation of the enzyme. The bistable NeoR is photoswitchable between a near-infrared-sensitive (NIR, λmax = 690 nm) highly fluorescent state (QF = 0.2) and a UV-sensitive non-fluorescent state, thereby modulating the activity by NIR pre-illumination. No other rhodopsin has been reported so far to be functional as a heterooligomer, or as having such a long wavelength absorption or high fluorescence yield. Site-specific mutagenesis and hybrid quantum mechanics/molecular mechanics simulations support the idea that the unusual photochemical properties result from the rigidity of the retinal chromophore and a unique counterion triad composed of two glutamic and one aspartic acids. These findings substantially expand our understanding of the natural potential and limitations of spectral tuning in rhodopsin photoreceptors.
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Affiliation(s)
- Matthias Broser
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany.
| | - Anika Spreen
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Patrick E Konold
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Enrico Schiewer
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Suliman Adam
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Veniamin Borin
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Reinhard Seifert
- Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | - John T M Kennis
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | | | - Peter Hegemann
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
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6
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Hernández-Rodríguez EW, Escorcia AM, van der Kamp MW, Montero-Alejo AL, Caballero J. Multi-scale simulation reveals that an amino acid substitution increases photosensitizing reaction inputs in Rhodopsins. J Comput Chem 2020; 41:2278-2295. [PMID: 32757375 DOI: 10.1002/jcc.26392] [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: 02/09/2020] [Revised: 06/27/2020] [Accepted: 07/04/2020] [Indexed: 11/11/2022]
Abstract
Evaluating the availability of molecular oxygen (O2 ) and energy of excited states in the retinal binding site of rhodopsin is a crucial challenging first step to understand photosensitizing reactions in wild-type (WT) and mutant rhodopsins by absorbing visible light. In the present work, energies of the ground and excited states related to 11-cis-retinal and the O2 accessibility to the β-ionone ring are evaluated inside WT and human M207R mutant rhodopsins. Putative O2 pathways within rhodopsins are identified by using molecular dynamics simulations, Voronoi-diagram analysis, and implicit ligand sampling while retinal energetic properties are investigated through density functional theory, and quantum mechanical/molecular mechanical methods. Here, the predictions reveal that an amino acid substitution can lead to enough energy and O2 accessibility in the core hosting retinal of mutant rhodopsins to favor the photosensitized singlet oxygen generation, which can be useful in understanding retinal degeneration mechanisms and in designing blue-lighting-absorbing proteic photosensitizers.
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Affiliation(s)
- Erix W Hernández-Rodríguez
- Laboratorio de Bioinformática y Química Computacional, Escuela de Química y Farmacia, Facultad de Medicina, Universidad Católica del Maule, Talca, Chile
| | - Andrés M Escorcia
- School of Biochemistry, University of Bristol, University Walk, Bristol, UK
| | | | - Ana L Montero-Alejo
- Departamento de Física, Facultad de Ciencias Naturales, Matemática y del Medio Ambiente (FCNMM), Universidad Tecnológica Metropolitana, Santiago, Chile
| | - Julio Caballero
- Departamento de Bioinformática, Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería, Universidad de Talca, Talca, Chile
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7
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Patel D, Barnes JE, Davies WIL, Stenkamp DL, Patel JS. Short-wavelength-sensitive 2 (Sws2) visual photopigment models combined with atomistic molecular simulations to predict spectral peaks of absorbance. PLoS Comput Biol 2020; 16:e1008212. [PMID: 33085657 PMCID: PMC7605715 DOI: 10.1371/journal.pcbi.1008212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/02/2020] [Accepted: 09/21/2020] [Indexed: 12/02/2022] Open
Abstract
For many species, vision is one of the most important sensory modalities for mediating essential tasks that include navigation, predation and foraging, predator avoidance, and numerous social behaviors. The vertebrate visual process begins when photons of the light interact with rod and cone photoreceptors that are present in the neural retina. Vertebrate visual photopigments are housed within these photoreceptor cells and are sensitive to a wide range of wavelengths that peak within the light spectrum, the latter of which is a function of the type of chromophore used and how it interacts with specific amino acid residues found within the opsin protein sequence. Minor differences in the amino acid sequences of the opsins are known to lead to large differences in the spectral peak of absorbance (i.e. the λmax value). In our prior studies, we developed a new approach that combined homology modeling and molecular dynamics simulations to gather structural information associated with chromophore conformation, then used it to generate statistical models for the accurate prediction of λmax values for photopigments derived from Rh1 and Rh2 amino acid sequences. In the present study, we test our novel approach to predict the λmax of phylogenetically distant Sws2 cone opsins. To build a model that can predict the λmax using our approach presented in our prior studies, we selected a spectrally-diverse set of 11 teleost Sws2 photopigments for which both amino acid sequence information and experimentally measured λmax values are known. The final first-order regression model, consisting of three terms associated with chromophore conformation, was sufficient to predict the λmax of Sws2 photopigments with high accuracy. This study further highlights the breadth of our approach in reliably predicting λmax values of Sws2 cone photopigments, evolutionary-more distant from template bovine RH1, and provided mechanistic insights into the role of known spectral tuning sites.
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Affiliation(s)
- Dharmeshkumar Patel
- Institute for Modeling Collaboration and Innovation (IMCI), University of Idaho, Moscow, ID, United States of America
| | - Jonathan E. Barnes
- Department of Physics, University of Idaho, Moscow, ID, United States of America
| | - Wayne I. L. Davies
- Umeå Centre for Molecular Medicine (UCMM), Umeå University, Umeå, Sweden
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
- The Oceans Graduate School, University of Western Australia, Perth, WA, Australia
- The Oceans Institute, University of Western Australia, Perth, WA, Australia
- Lions Eye Institute, University of Western Australia, Perth, WA, Australia
| | - Deborah L. Stenkamp
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States of America
- Institute for Bioinformatics and Evolutionary Biology, University of Idaho, Moscow, ID, United States of America
| | - Jagdish Suresh Patel
- Institute for Modeling Collaboration and Innovation (IMCI), University of Idaho, Moscow, ID, United States of America
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States of America
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8
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Orozco-Gonzalez Y, Kabir MP, Gozem S. Electrostatic Spectral Tuning Maps for Biological Chromophores. J Phys Chem B 2019; 123:4813-4824. [DOI: 10.1021/acs.jpcb.9b00489] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | - Mohammad Pabel Kabir
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302, United States
| | - Samer Gozem
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302, United States
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9
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Wiebeler C, Rao AG, Gärtner W, Schapiro I. Die effektive Konjugationslänge ist für die spektrale Verschiebung im rot/grün schaltenden Cyanobakteriochrom Slr1393g3 verantwortlich. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201810266] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Christian Wiebeler
- Fritz Haber Center for Molecular Dynamics Research; Institute of Chemistry; The Hebrew University of Jerusalem; Jerusalem 91904 Israel
| | - Aditya G. Rao
- Fritz Haber Center for Molecular Dynamics Research; Institute of Chemistry; The Hebrew University of Jerusalem; Jerusalem 91904 Israel
| | - Wolfgang Gärtner
- Institut für Analytische Chemie; Fakultät für Chemie und Mineralogie; Universität Leipzig; 04103 Leipzig Germany
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics Research; Institute of Chemistry; The Hebrew University of Jerusalem; Jerusalem 91904 Israel
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10
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Wiebeler C, Rao AG, Gärtner W, Schapiro I. The Effective Conjugation Length Is Responsible for the Red/Green Spectral Tuning in the Cyanobacteriochrome Slr1393g3. Angew Chem Int Ed Engl 2019; 58:1934-1938. [PMID: 30508317 DOI: 10.1002/anie.201810266] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Indexed: 01/19/2023]
Abstract
The origin of the spectral shift from a red- to a green-absorbing form in a cyanobacteriochrome, Slr1393g3, was identified by combined quantum mechanics/molecular mechanics simulations. This protein, related to classical phytochromes, carries the open-chain tetrapyrrole chromophore phycocyanobilin. Our calculations reveal that the effective conjugation length in the chromophore becomes shorter upon conversion from the red to the green form. This is related to the planarity of the entire chromophore. A large distortion was found for the terminal pyrrole rings A and D; however, the D ring contributes more strongly to the photoproduct tuning, despite a larger change in the twist of the A ring. Our findings implicate that the D ring twist can be exploited to regulate the absorption of the photoproduct. Hence, mutations that affect the D ring twist can lead to rational tuning of the photoproduct absorption, allowing the tailoring of cyanobacteriochromes for biotechnological applications such as optogenetics and bioimaging.
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Affiliation(s)
- Christian Wiebeler
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Aditya G Rao
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Wolfgang Gärtner
- Institut für Analytische Chemie, Fakultät für Chemie und Mineralogie, Universität Leipzig, 04103, Leipzig, Germany
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
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11
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Fiedor L, Pilch M. Side Methyl Groups Control the Conformation and Contribute to Symmetry Breaking of Isoprenoid Chromophores. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Leszek Fiedor
- Faculty of Biochemistry, Biophysics and BiotechnologyJagiellonian University Gronostajowa 7 30-387 Kraków Poland
| | - Mariusz Pilch
- Faculty of Biochemistry, Biophysics and BiotechnologyJagiellonian University Gronostajowa 7 30-387 Kraków Poland
- Faculty of ChemistryJagiellonian University Gronostajowa 2 30-387 Kraków Poland
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12
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Fiedor L, Pilch M. Side Methyl Groups Control the Conformation and Contribute to Symmetry Breaking of Isoprenoid Chromophores. Angew Chem Int Ed Engl 2018; 57:6501-6506. [PMID: 29601118 DOI: 10.1002/anie.201802094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Indexed: 01/02/2023]
Abstract
Ab initio DFT computations reveal that the essential structural and photophysical features of the conjugated π-electron system of retinal and carotenoids are dictated by "innocent" methyl substituents. These methyl groups shape the conformation and symmetry of the isoprenoid chromophores by causing a sigmoidal distortion of the polyene skeleton and increasing its flexibility, which facilitates fitting to their binding pockets in proteins. Comparison of in vacuo conformations of the chromophores with their native (protein-bound) conformations showed, surprisingly, that the peripheral groups and interactions with the protein environment are much less significant than the methyl side groups in tuning their structural features. The methyl side groups also contribute to a loss of symmetry elements specific to linear polyenes. In effect, the symmetry-imposed restrictions on the chromophore electronic properties are disabled, which is of tremendous relevance to their photophysics. This is evidenced by their non-negligible permanent dipole moments and by the simulated and experimentally measured circular dichroism spectra, which necessarily reflect the chirality of the conjugated π-electron system.
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Affiliation(s)
- Leszek Fiedor
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Mariusz Pilch
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.,Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
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13
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Patel JS, Brown CJ, Ytreberg FM, Stenkamp DL. Predicting peak spectral sensitivities of vertebrate cone visual pigments using atomistic molecular simulations. PLoS Comput Biol 2018; 14:e1005974. [PMID: 29364888 PMCID: PMC5798944 DOI: 10.1371/journal.pcbi.1005974] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 02/05/2018] [Accepted: 01/13/2018] [Indexed: 11/19/2022] Open
Abstract
Vision is the dominant sensory modality in many organisms for foraging, predator avoidance, and social behaviors including mate selection. Vertebrate visual perception is initiated when light strikes rod and cone photoreceptors within the neural retina of the eye. Sensitivity to individual colors, i.e., peak spectral sensitivities (λmax) of visual pigments, are a function of the type of chromophore and the amino acid sequence of the associated opsin protein in the photoreceptors. Large differences in peak spectral sensitivities can result from minor differences in amino acid sequence of cone opsins. To determine how minor sequence differences could result in large spectral shifts we selected a spectrally-diverse group of 14 teleost Rh2 cone opsins for which sequences and λmax are experimentally known. Classical molecular dynamics simulations were carried out after embedding chromophore-associated homology structures within explicit bilayers and water. These simulations revealed structural features of visual pigments, particularly within the chromophore, that contributed to diverged spectral sensitivities. Statistical tests performed on all the observed structural parameters associated with the chromophore revealed that a two-term, first-order regression model was sufficient to accurately predict λmax over a range of 452-528 nm. The approach was accurate, efficient and simple in that site-by-site molecular modifications or complex quantum mechanics models were not required to predict λmax. These studies identify structural features associated with the chromophore that may explain diverged spectral sensitivities, and provide a platform for future, functionally predictive opsin modeling.
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Affiliation(s)
- Jagdish Suresh Patel
- Center for Modeling Complex Interactions, University of Idaho, Moscow, ID, United States of America
| | - Celeste J. Brown
- Center for Modeling Complex Interactions, University of Idaho, Moscow, ID, United States of America
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States of America
- Department of Physics, University of Idaho, Moscow, ID, United States of America
| | - F. Marty Ytreberg
- Center for Modeling Complex Interactions, University of Idaho, Moscow, ID, United States of America
- Department of Physics, University of Idaho, Moscow, ID, United States of America
- Institute for Bioinformatics and Evolutionary Biology, University of Idaho, Moscow, ID, United States of America
| | - Deborah L. Stenkamp
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States of America
- Institute for Bioinformatics and Evolutionary Biology, University of Idaho, Moscow, ID, United States of America
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14
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Varsano D, Caprasecca S, Coccia E. Theoretical description of protein field effects on electronic excitations of biological chromophores. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:013002. [PMID: 27830666 DOI: 10.1088/0953-8984/29/1/013002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Photoinitiated phenomena play a crucial role in many living organisms. Plants, algae, and bacteria absorb sunlight to perform photosynthesis, and convert water and carbon dioxide into molecular oxygen and carbohydrates, thus forming the basis for life on Earth. The vision of vertebrates is accomplished in the eye by a protein called rhodopsin, which upon photon absorption performs an ultrafast isomerisation of the retinal chromophore, triggering the signal cascade. Many other biological functions start with the photoexcitation of a protein-embedded pigment, followed by complex processes comprising, for example, electron or excitation energy transfer in photosynthetic complexes. The optical properties of chromophores in living systems are strongly dependent on the interaction with the surrounding environment (nearby protein residues, membrane, water), and the complexity of such interplay is, in most cases, at the origin of the functional diversity of the photoactive proteins. The specific interactions with the environment often lead to a significant shift of the chromophore excitation energies, compared with their absorption in solution or gas phase. The investigation of the optical response of chromophores is generally not straightforward, from both experimental and theoretical standpoints; this is due to the difficulty in understanding diverse behaviours and effects, occurring at different scales, with a single technique. In particular, the role played by ab initio calculations in assisting and guiding experiments, as well as in understanding the physics of photoactive proteins, is fundamental. At the same time, owing to the large size of the systems, more approximate strategies which take into account the environmental effects on the absorption spectra are also of paramount importance. Here we review the recent advances in the first-principle description of electronic and optical properties of biological chromophores embedded in a protein environment. We show their applications on paradigmatic systems, such as the light-harvesting complexes, rhodopsin and green fluorescent protein, emphasising the theoretical frameworks which are of common use in solid state physics, and emerging as promising tools for biomolecular systems.
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Affiliation(s)
- Daniele Varsano
- S3 Center, CNR Institute of Nanoscience, Via Campi 213/A, 41125 Modena, Italy
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15
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Melaccio F, del Carmen Marín M, Valentini A, Montisci F, Rinaldi S, Cherubini M, Yang X, Kato Y, Stenrup M, Orozco-Gonzalez Y, Ferré N, Luk HL, Kandori H, Olivucci M. Toward Automatic Rhodopsin Modeling as a Tool for High-Throughput Computational Photobiology. J Chem Theory Comput 2016; 12:6020-6034. [DOI: 10.1021/acs.jctc.6b00367] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Federico Melaccio
- Department
of Biotechnology, Chemistry e Pharmacy, Università di Siena, via A. Moro 2, I-53100 Siena, Italy
| | - María del Carmen Marín
- Department
of Biotechnology, Chemistry e Pharmacy, Università di Siena, via A. Moro 2, I-53100 Siena, Italy
- Department
of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Alessio Valentini
- Department
of Biotechnology, Chemistry e Pharmacy, Università di Siena, via A. Moro 2, I-53100 Siena, Italy
| | - Fabio Montisci
- Department
of Biotechnology, Chemistry e Pharmacy, Università di Siena, via A. Moro 2, I-53100 Siena, Italy
| | - Silvia Rinaldi
- Department
of Biotechnology, Chemistry e Pharmacy, Università di Siena, via A. Moro 2, I-53100 Siena, Italy
| | - Marco Cherubini
- Department
of Biotechnology, Chemistry e Pharmacy, Università di Siena, via A. Moro 2, I-53100 Siena, Italy
| | - Xuchun Yang
- Department
of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Yoshitaka Kato
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Japan
| | - Michael Stenrup
- Aix-Marseille Université, CNRS, ICR, 13284 Marseille, France
| | - Yoelvis Orozco-Gonzalez
- Department
of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
- Institut
de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 Université de Strasbourg-CNRS, F-67034 Strasbourg, France
- USIAS
Institut d’Études Avancées, Université de Strasbourg, 5 allée du Général Rouvillois, F-67083 Strasbourg, France
| | - Nicolas Ferré
- Aix-Marseille Université, CNRS, ICR, 13284 Marseille, France
| | - Hoi Ling Luk
- Department
of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Hideki Kandori
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Japan
| | - Massimo Olivucci
- Department
of Biotechnology, Chemistry e Pharmacy, Università di Siena, via A. Moro 2, I-53100 Siena, Italy
- Department
of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
- Institut
de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 Université de Strasbourg-CNRS, F-67034 Strasbourg, France
- USIAS
Institut d’Études Avancées, Université de Strasbourg, 5 allée du Général Rouvillois, F-67083 Strasbourg, France
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16
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Suomivuori CM, Lang L, Sundholm D, Gamiz-Hernandez AP, Kaila VRI. Tuning the Protein-Induced Absorption Shifts of Retinal in Engineered Rhodopsin Mimics. Chemistry 2016; 22:8254-61. [DOI: 10.1002/chem.201505126] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/23/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Carl-Mikael Suomivuori
- Department of Chemistry; University of Helsinki; A.I. Virtanens plats 1, P.O. Box 55 FI-00014 Helsinki Finland
- Department Chemie; Technische Universität München (TUM); Lichtenbergstrasse 4 85747 Garching Germany
| | - Lucas Lang
- Department Chemie; Technische Universität München (TUM); Lichtenbergstrasse 4 85747 Garching Germany
| | - Dage Sundholm
- Department of Chemistry; University of Helsinki; A.I. Virtanens plats 1, P.O. Box 55 FI-00014 Helsinki Finland
| | - Ana P. Gamiz-Hernandez
- Department Chemie; Technische Universität München (TUM); Lichtenbergstrasse 4 85747 Garching Germany
| | - Ville R. I. Kaila
- Department Chemie; Technische Universität München (TUM); Lichtenbergstrasse 4 85747 Garching Germany
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17
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Srinivasan S, Cordomí A, Ramon E, Garriga P. Beyond spectral tuning: human cone visual pigments adopt different transient conformations for chromophore regeneration. Cell Mol Life Sci 2016; 73:1253-63. [PMID: 26387074 PMCID: PMC11108329 DOI: 10.1007/s00018-015-2043-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 01/01/2023]
Abstract
Human red and green visual pigments are seven transmembrane receptors of cone photoreceptor cells of the retina that mediate color vision. These pigments share a very high degree of homology and have been assumed to feature analogous structural and functional properties. We report on a different regeneration mechanism among red and green cone opsins with retinal analogs using UV-Vis/fluorescence spectroscopic analyses, molecular modeling and site-directed mutagenesis. We find that photoactivated green cone opsin adopts a transient conformation which regenerates via an unprotonated Schiff base linkage with its natural chromophore, whereas red cone opsin forms a typical protonated Schiff base. The chromophore regeneration kinetics is consistent with a secondary retinal uptake by the cone pigments. Overall, our findings reveal, for the first time, structural differences in the photoactivated conformation between red and green cone pigments that may be linked to their molecular evolution, and support the proposal of secondary retinal binding to visual pigments, in addition to binding to the canonical primary site, which may serve as a regulatory mechanism of dark adaptation in the phototransduction process.
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Affiliation(s)
- Sundaramoorthy Srinivasan
- Departament d'Enginyeria Química, Centre de Biotecnologia Molecular, Universitat Politècnica de Catalunya, Rambla de Sant Nebridi 22, 08222, Terrassa, Spain
| | - Arnau Cordomí
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Barcelona, Spain
| | - Eva Ramon
- Departament d'Enginyeria Química, Centre de Biotecnologia Molecular, Universitat Politècnica de Catalunya, Rambla de Sant Nebridi 22, 08222, Terrassa, Spain
| | - Pere Garriga
- Departament d'Enginyeria Química, Centre de Biotecnologia Molecular, Universitat Politècnica de Catalunya, Rambla de Sant Nebridi 22, 08222, Terrassa, Spain.
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18
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Ockenfels A, Schapiro I, Gärtner W. Rhodopsins carrying modified chromophores--the 'making of', structural modelling and their light-induced reactivity. Photochem Photobiol Sci 2016; 15:297-308. [PMID: 26860474 DOI: 10.1039/c5pp00322a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A series of vitamin-A aldehydes (retinals) with modified alkyl group substituents (9-demethyl-, 9-ethyl-, 9-isopropyl-, 10-methyl, 10-methyl-13-demethyl-, and 13-demethyl retinal) was synthesized and their 11-cis isomers were used as chromophores to reconstitute the visual pigment rhodopsin. Structural changes were selectively introduced around the photoisomerizing C11=C12 bond. The effect of these structural changes on rhodopsin formation and bleaching was determined. Global fit of assembly kinetics yielded lifetimes and spectral features of the assembly intermediates. Rhodopsin formation proceeds stepwise with prolonged lifetimes especially for 9-demethyl retinal (longest lifetime τ3 = 7500 s, cf., 3500 s for retinal), and for 10-methyl retinal (τ3 = 7850 s). These slowed-down processes are interpreted as either a loss of fixation (9dm) or an increased steric hindrance (10me) during the conformational adjustment within the protein. Combined quantum mechanics and molecular mechanics (QM/MM) simulations provided structural insight into the retinal analogues-assembled, full-length rhodopsins. Extinction coefficients, quantum yields and kinetics of the bleaching process (μs-to-ms time range) were determined. Global fit analysis yielded lifetimes and spectral features of bleaching intermediates, revealing remarkably altered kinetics: whereas the slowest process of wild-type rhodopsin and of bleached and 11-cis retinal assembled rhodopsin takes place with lifetimes of 7 and 3.8 s, respectively, this process for 10-methyl-13-demethyl retinal was nearly 10 h (34670 s), coming to completion only after ca. 50 h. The structural changes in retinal derivatives clearly identify the precise interactions between chromophore and protein during the light-induced changes that yield the outstanding efficiency of rhodopsin.
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Affiliation(s)
- Andreas Ockenfels
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim, Germany.
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19
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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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20
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Varsano D, Coccia E, Pulci O, Conte AM, Guidoni L. Ground state structures and electronic excitations of biological chromophores at Quantum Monte Carlo/Many Body Green’s Function Theory level. COMPUT THEOR CHEM 2014. [DOI: 10.1016/j.comptc.2014.03.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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21
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22
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Campomanes P, Neri M, Horta BAC, Röhrig UF, Vanni S, Tavernelli I, Rothlisberger U. Origin of the Spectral Shifts among the Early Intermediates of the Rhodopsin Photocycle. J Am Chem Soc 2014; 136:3842-51. [DOI: 10.1021/ja411303v] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Pablo Campomanes
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Marilisa Neri
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Bruno A. C. Horta
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Ute F. Röhrig
- Molecular Modeling
Group, Swiss Institute of
Bioinformatics, CH-1015 Lausanne, Switzerland
| | - Stefano Vanni
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Ivano Tavernelli
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
| | - Ursula Rothlisberger
- Laboratory
of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale Lausanne, CH-1015 Lausanne, Switzerland
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23
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Mehler M, Scholz F, Ullrich SJ, Mao J, Braun M, Brown LJ, Brown RCD, Fiedler SA, Becker-Baldus J, Wachtveitl J, Glaubitz C. The EF loop in green proteorhodopsin affects conformation and photocycle dynamics. Biophys J 2014; 105:385-97. [PMID: 23870260 DOI: 10.1016/j.bpj.2013.06.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 11/20/2022] Open
Abstract
The proteorhodopsin family consists of retinal proteins of marine bacterial origin with optical properties adjusted to their local environments. For green proteorhodopsin, a highly specific mutation in the EF loop, A178R, has been found to cause a surprisingly large redshift of 20 nm despite its distance from the chromophore. Here, we analyze structural and functional consequences of this EF loop mutation by time-resolved optical spectroscopy and solid-state NMR. We found that the primary photoreaction and the formation of the K-like photo intermediate is almost pH-independent and slower compared to the wild-type, whereas the decay of the K-intermediate is accelerated, suggesting structural changes within the counterion complex upon mutation. The photocycle is significantly elongated mainly due to an enlarged lifetime of late photo intermediates. Multidimensional MAS-NMR reveals mutation-induced chemical shift changes propagating from the EF loop to the chromophore binding pocket, whereas dynamic nuclear polarization-enhanced (13)C-double quantum MAS-NMR has been used to probe directly the retinylidene conformation. Our data show a modified interaction network between chromophore, Schiff base, and counterion complex explaining the altered optical and kinetic properties. In particular, the mutation-induced distorted structure in the EF loop weakens interactions, which help reorienting helix F during the reprotonation step explaining the slower photocycle. These data lead to the conclusion that the EF loop plays an important role in proton uptake from the cytoplasm but our data also reveal a clear interaction pathway between the EF loop and retinal binding pocket, which might be an evolutionary conserved communication pathway in retinal proteins.
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Affiliation(s)
- Michaela Mehler
- Institute of Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt, Germany
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24
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Bassolino G, Sovdat T, Liebel M, Schnedermann C, Odell B, Claridge TD, Kukura P, Fletcher SP. Synthetic Control of Retinal Photochemistry and Photophysics in Solution. J Am Chem Soc 2014; 136:2650-8. [DOI: 10.1021/ja4121814] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Giovanni Bassolino
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K
| | - Tina Sovdat
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Matz Liebel
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K
| | - Christoph Schnedermann
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K
| | - Barbara Odell
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Timothy D.W. Claridge
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Philipp Kukura
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K
| | - Stephen P. Fletcher
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
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25
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Ernst OP, Lodowski DT, Elstner M, Hegemann P, Brown L, Kandori H. Microbial and animal rhodopsins: structures, functions, and molecular mechanisms. Chem Rev 2014; 114:126-63. [PMID: 24364740 PMCID: PMC3979449 DOI: 10.1021/cr4003769] [Citation(s) in RCA: 781] [Impact Index Per Article: 78.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Indexed: 12/31/2022]
Affiliation(s)
- Oliver P. Ernst
- Departments
of Biochemistry and Molecular Genetics, University of Toronto, 1 King’s College Circle, Medical Sciences Building, Toronto, Ontario M5S 1A8, Canada
| | - David T. Lodowski
- Center
for Proteomics and Bioinformatics, Case
Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Marcus Elstner
- Institute
for Physical Chemistry, Karlsruhe Institute
of Technology, Kaiserstrasse
12, 76131 Karlsruhe, Germany
| | - Peter Hegemann
- Institute
of Biology, Experimental Biophysics, Humboldt-Universität
zu Berlin, Invalidenstrasse
42, 10115 Berlin, Germany
| | - Leonid
S. Brown
- Department
of Physics and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Hideki Kandori
- Department
of Frontier Materials, Nagoya Institute
of Technology, Showa-ku, Nagoya 466-8555, Japan
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26
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Lasogga L, Bricks J, Merk V, Kneipp J, Rettig W. Electric field effects on donor–acceptor dyes: A model compound study using UV/vis absorption and Raman spectroscopy. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2013.11.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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27
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Rivalta I, Nenov A, Garavelli M. Modelling retinal chromophores photoisomerization: from minimal models in vacuo to ultimate bidimensional spectroscopy in rhodopsins. Phys Chem Chem Phys 2014; 16:16865-79. [DOI: 10.1039/c3cp55211j] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Modelling of retinal photoisomerization in different environments is reviewed and ultimate ultrafast electronic spectroscopy is proposed for obtaining new insights.
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Affiliation(s)
- Ivan Rivalta
- Université de Lyon
- CNRS
- 69364 Lyon, Cedex 07, France
- Dipartimento di Chimica “Giacomo Ciamician”
- Università di Bologna
| | - Artur Nenov
- Dipartimento di Chimica “Giacomo Ciamician”
- Università di Bologna
- 40126 Bologna, Italy
| | - Marco Garavelli
- Université de Lyon
- CNRS
- 69364 Lyon, Cedex 07, France
- Dipartimento di Chimica “Giacomo Ciamician”
- Università di Bologna
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28
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Álvarez R, Vaz B, Gronemeyer H, de Lera ÁR. Functions, therapeutic applications, and synthesis of retinoids and carotenoids. Chem Rev 2013; 114:1-125. [PMID: 24266866 DOI: 10.1021/cr400126u] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Rosana Álvarez
- Departamento de Química Orgánica, Centro de Investigación Biomédica (CINBIO), and Instituto de Investigación Biomédica de Vigo (IBIV), Universidade de Vigo , 36310 Vigo, Spain
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29
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Wang W, Geiger JH, Borhan B. The photochemical determinants of color vision: revealing how opsins tune their chromophore's absorption wavelength. Bioessays 2013; 36:65-74. [PMID: 24323922 DOI: 10.1002/bies.201300094] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The evolution of a variety of important chromophore-dependent biological processes, including microbial light sensing and mammalian color vision, relies on protein modifications that alter the spectral characteristics of a bound chromophore. Three different color opsins share the same chromophore, but have three distinct absorptions that together cover the entire visible spectrum, giving rise to trichromatic vision. The influence of opsins on the absorbance of the chromophore has been studied through methods such as model compounds, opsin mutagenesis, and computational modeling. The recent development of rhodopsin mimic that uses small soluble proteins to recapitulate the binding and wavelength tuning of the native opsins provides a new platform for studying protein-regulated spectral tuning. The ability to achieve far-red shifted absorption in the rhodopsin mimic system was attributed to a combination of the lack of a counteranion proximal to the iminium, and a uniformly neutral electrostatic environment surrounding the chromophore.
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Affiliation(s)
- Wenjing Wang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
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30
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Huntress MM, Gozem S, Malley KR, Jailaubekov AE, Vasileiou C, Vengris M, Geiger JH, Borhan B, Schapiro I, Larsen DS, Olivucci M. Toward an Understanding of the Retinal Chromophore in Rhodopsin Mimics. J Phys Chem B 2013; 117:10053-70. [DOI: 10.1021/jp305935t] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mark M. Huntress
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio
43402, United States
| | - Samer Gozem
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio
43402, United States
| | - Konstantin R. Malley
- Department
of Chemistry, University of California Davis, One Shields Avenure,
Davis, California 95616, United States
| | - Askat E. Jailaubekov
- Department
of Chemistry, University of California Davis, One Shields Avenure,
Davis, California 95616, United States
| | - Chrysoula Vasileiou
- Department of Chemistry, Michigan State University, Lansing, Michigan 48824,
United States
| | - Mikas Vengris
- Department
of Chemistry, University of California Davis, One Shields Avenure,
Davis, California 95616, United States
- Faculty of
Physics, Vilnius University, Sauletekio
10 LT10223 Vilnius,
Lithuania
| | - James H. Geiger
- Department of Chemistry, Michigan State University, Lansing, Michigan 48824,
United States
| | - Babak Borhan
- Department of Chemistry, Michigan State University, Lansing, Michigan 48824,
United States
| | - Igor Schapiro
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio
43402, United States
| | - Delmar S. Larsen
- Department
of Chemistry, University of California Davis, One Shields Avenure,
Davis, California 95616, United States
| | - Massimo Olivucci
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio
43402, United States
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31
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Hernández-Rodríguez EW, Montero-Alejo AL, López R, Sánchez-García E, Montero-Cabrera LA, García de la Vega JM. Electron density deformations provide new insights into the spectral shift of rhodopsins. J Comput Chem 2013; 34:2460-71. [DOI: 10.1002/jcc.23414] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/26/2013] [Accepted: 07/27/2013] [Indexed: 11/08/2022]
Affiliation(s)
| | - Ana Lilian Montero-Alejo
- Laboratorio de Química Computacional y Teórica; Departamento de Química Física; Universidad de La Habana; Havana; 10400; Cuba
| | - Rafael López
- Departamento de Química Física Aplicada; Facultad de Ciencias, Universidad Autónoma de Madrid; Madrid; 28049; Spain
| | - Elsa Sánchez-García
- Max-Planck-Institut für Kohlenforschung; Kaiser-Wilhelm-Platz 1; Mülheim an der Ruhr; 45470; Germany
| | - Luis Alberto Montero-Cabrera
- Laboratorio de Química Computacional y Teórica; Departamento de Química Física; Universidad de La Habana; Havana; 10400; Cuba
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32
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Valsson O, Campomanes P, Tavernelli I, Rothlisberger U, Filippi C. Rhodopsin Absorption from First Principles: Bypassing Common Pitfalls. J Chem Theory Comput 2013; 9:2441-54. [PMID: 26583734 DOI: 10.1021/ct3010408] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bovine rhodopsin is the most extensively studied retinal protein and is considered the prototype of this important class of photosensitive biosystems involved in the process of vision. Many theoretical investigations have attempted to elucidate the role of the protein matrix in modulating the absorption of retinal chromophore in rhodopsin, but, while generally agreeing in predicting the correct location of the absorption maximum, they often reached contradicting conclusions on how the environment tunes the spectrum. To address this controversial issue, we combine here a thorough structural and dynamical characterization of rhodopsin with a careful validation of its excited-state properties via the use of a wide range of state-of-the-art quantum chemical approaches including various flavors of time-dependent density functional theory (TDDFT), different multireference perturbative schemes (CASPT2 and NEVPT2), and quantum Monte Carlo (QMC) methods. Through extensive quantum mechanical/molecular mechanical (QM/MM) molecular dynamics simulations, we obtain a comprehensive structural description of the chromophore-protein system and sample a wide range of thermally accessible configurations. We show that, in order to obtain reliable excitation properties, it is crucial to employ a sufficient number of representative configurations of the system. In fact, the common use of a single, ad hoc structure can easily lead to an incorrect model and an agreement with experimental absorption spectra due to cancelation of errors. Finally, we show that, to properly account for polarization effects on the chromophore and to quench the large blue-shift induced by the counterion on the excitation energies, it is necessary to adopt an enhanced description of the protein environment as given by a large quantum region including as many as 250 atoms.
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Affiliation(s)
- Omar Valsson
- MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Pablo Campomanes
- Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Ivano Tavernelli
- Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Ursula Rothlisberger
- Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Claudia Filippi
- MESA+ Institute for Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
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33
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Ruckenbauer M, Barbatti M, Müller T, Lischka H. Nonadiabatic photodynamics of a retinal model in polar and nonpolar environment. J Phys Chem A 2013; 117:2790-9. [PMID: 23470211 PMCID: PMC3619535 DOI: 10.1021/jp400401f] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The nonadiabatic photodynamics of
the all-trans-2,4-pentadiene-iminium cation (protonated
Schiff base 3, PSB3) and
the all-trans-3-methyl-2,4-pentadiene-iminium cation
(MePSB3) were investigated in the gas phase and in polar (aqueous)
and nonpolar (n-hexane) solutions by means of surface
hopping using a multireference configuration-interaction (MRCI) quantum
mechanical/molecular mechanics (QM/MM) level. Spectra, lifetimes for
radiationless deactivation to the ground state, and structural and
electronic parameters are compared. A strong influence of the polar
solvent on the location of the crossing seam, in particular in the
bond length alternation (BLA) coordinate, is found. Additionally,
inclusion of the polar solvent changes the orientation of the intersection
cone from sloped in the gas phase to peaked, thus enhancing considerably
its efficiency for deactivation of the molecular system to the ground
state. These factors cause, especially for MePSB3, a substantial decrease
in the lifetime of the excited state despite the steric inhibition
by the solvent.
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Affiliation(s)
- Matthias Ruckenbauer
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090 Vienna, Austria
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34
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Falklöf O, Durbeej B. Modeling of phytochrome absorption spectra. J Comput Chem 2013; 34:1363-74. [DOI: 10.1002/jcc.23265] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/31/2013] [Accepted: 02/07/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Olle Falklöf
- Division of Computational Physics; IFM; Linköping University; SE-581 83; Linköping; Sweden
| | - Bo Durbeej
- Division of Computational Physics; IFM; Linköping University; SE-581 83; Linköping; Sweden
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35
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Sekharan S, Wei JN, Batista VS. The Active Site of Melanopsin: The Biological Clock Photoreceptor. J Am Chem Soc 2012; 134:19536-9. [DOI: 10.1021/ja308763b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Sivakumar Sekharan
- Department
of Chemistry, Yale University, New Haven,
Connecticut 06520-8107, United States
| | - Jennifer N. Wei
- Department
of Chemistry, Yale University, New Haven,
Connecticut 06520-8107, United States
| | - Victor S. Batista
- Department
of Chemistry, Yale University, New Haven,
Connecticut 06520-8107, United States
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36
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Sekharan S, Katayama K, Kandori H, Morokuma K. Color vision: "OH-site" rule for seeing red and green. J Am Chem Soc 2012; 134:10706-12. [PMID: 22663599 DOI: 10.1021/ja304820p] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eyes gather information, and color forms an extremely important component of the information, more so in the case of animals to forage and navigate within their immediate environment. By using the ONIOM (QM/MM) (ONIOM = our own N-layer integrated molecular orbital plus molecular mechanics) method, we report a comprehensive theoretical analysis of the structure and molecular mechanism of spectral tuning of monkey red- and green-sensitive visual pigments. We show that interaction of retinal with three hydroxyl-bearing amino acids near the β-ionone ring part of the retinal in opsin, A164S, F261Y, and A269T, increases the electron delocalization, decreases the bond length alternation, and leads to variation in the wavelength of maximal absorbance of the retinal in the red- and green-sensitive visual pigments. On the basis of the analysis, we propose the "OH-site" rule for seeing red and green. This rule is also shown to account for the spectral shifts obtained from hydroxyl-bearing amino acids near the Schiff base in different visual pigments: at site 292 (A292S, A292Y, and A292T) in bovine and at site 111 (Y111) in squid opsins. Therefore, the OH-site rule is shown to be site-specific and not pigment-specific and thus can be used for tracking spectral shifts in any visual pigment.
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Affiliation(s)
- Sivakumar Sekharan
- Cherry L. Emerson Center for Scientific Computation, Department of Chemistry, Emory University, Atlanta Georgia 30322, USA.
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37
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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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38
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Hernández-Rodríguez EW, Sánchez-García E, Crespo-Otero R, Montero-Alejo AL, Montero LA, Thiel W. Understanding Rhodopsin Mutations Linked to the Retinitis pigmentosa Disease: a QM/MM and DFT/MRCI Study. J Phys Chem B 2012; 116:1060-76. [DOI: 10.1021/jp2037334] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Erix Wiliam Hernández-Rodríguez
- Departamento de Bioquímica, Instituto de Ciencias Básicas y Preclínicas “Victoria de Girón”, 11600 Havana City, Cuba, and Charité Centrum für Innere Medizin und Dermatologie, Biomedizinisches Forschungszentrum, Campus Virchow, Charité-Universitätsmedizin, 13353 Berlin, Germany
| | | | | | - Ana Lilian Montero-Alejo
- Laboratorio de Química Computacional y Teórica, Departamento de Química Física, Universidad de La Habana, 10400 Havana City, Cuba
| | - Luis Alberto Montero
- Laboratorio de Química Computacional y Teórica, Departamento de Química Física, Universidad de La Habana, 10400 Havana City, Cuba
| | - Walter Thiel
- Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, 45470 Germany
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39
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Hasegawa JY, Fujimoto KJ, Nakatsuji H. Color tuning in photofunctional proteins. Chemphyschem 2011; 12:3106-15. [PMID: 21990164 DOI: 10.1002/cphc.201100452] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 08/24/2011] [Indexed: 11/11/2022]
Abstract
Depending on protein environment, a single photofunctional chromophore shows a wide variation of photoabsorption/emission energies. This photobiological phenomenon, known as color tuning, is observed in human visual cone pigments, firefly luciferase, and red fluorescent protein. We investigate the origin of color tuning by quantum chemical calculations on the excited states: symmetry-adapted cluster-configuration interaction (SAC-CI) method for excited states and a combined quantum mechanical (QM)/molecular mechanical (MM) method for protein environments. This Minireview summarizes our theoretical studies on the above three systems and explains a common feature of their color-tuning mechanisms. It also discuss the possibility of artificial color tuning toward a rational design of photoabsorption/emission properties.
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Affiliation(s)
- Jun-ya Hasegawa
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan.
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40
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Sekharan S, Yokoyama S, Morokuma K. Quantum mechanical/molecular mechanical structure, enantioselectivity, and spectroscopy of hydroxyretinals and insights into the evolution of color vision in small white butterflies. J Phys Chem B 2011; 115:15380-8. [PMID: 22087641 DOI: 10.1021/jp208107r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Since Vogt's discovery of A(3)-retinal or 3-hydroxyretinal in insects in 1983 and Matsui's discovery of A(4)-retinal or 4-hydroxyretinal in firefly squid in 1988, hydroxyretinal-protein interactions mediating vision have remained largely unexplored. In the present study, A(3)- and A(4)-retinals are theoretically incorporated into squid and bovine visual pigments by use of the hybrid quantum mechanics/molecular mechanics [SORCI+Q//B3LYP/6-31G(d):Amber96] method, and insights into structure, enantioselectivity, and spectroscopy are gathered and presented for the first time. Contrary to general perception, our findings rule out the formation of a hydrogen bond between the hydroxyl-bearing β-ionone ring portion of retinal and opsin. Compared to A(1)-pigments, A(3)- and A(4)-pigments exhibit slightly blue-shifted absorption maxima due to increase in bond-length alternation of the hydroxyretinal. We suggest that (i) the binding site of firefly squid (Watasenia scintillans) opsin is very similar to that of the Japanese common squid (Todarodes pacificus) opsin; (ii) the molecular mechanism of spectral tuning in small white butterflies involve sites S116 and T185 and breaking of a hydrogen bond between sites E180 and T185; and finally (iii) A(3)-retinal may have occurred during the conversion of A(1)- to A(2)-retinal and insects may have acquired them, in order to absorb light in the blue-green wavelength region and to speed up the G-protein signaling cascade.
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Affiliation(s)
- Sivakumar Sekharan
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
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41
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Welke K, Frähmcke JS, Watanabe HC, Hegemann P, Elstner M. Color tuning in binding pocket models of the chlamydomonas-type channelrhodopsins. J Phys Chem B 2011; 115:15119-28. [PMID: 22077286 DOI: 10.1021/jp2085457] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We examined the shift of absorption maxima between the chlamydomonas-type channelrhodopsins (ChRs) and bacteriorhodopsin (BR). Starting from the BR X-ray structure, we modeled the color tuning in the binding pockets of the ChRs by mutating up to 28 amino acids in the vicinity of the chromophore. By applying the efficient self-consistent charge density functional tight binding (SCC-DFTB) method in a quantum mechanical/molecular mechanical (QM/MM) framework, including explicit polarization and calculating excitation energies with the semiempirical OM2/MRCI method and the ab initio SORCI method, we have shown that multiple mutations in the binding pocket of BR causes large hypsochromic shifts that are of the same order as the experimentally observed shifts of the absorption maxima between BR and the ChRs. This study further demonstrates that mutations in the proximity of the Schiff base and complex counterion lead to a stronger but more flexible interaction with the retinal, which could serve as a possible explanation for the spectral patterns found in the ChRs.
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Affiliation(s)
- Kai Welke
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
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42
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Sekharan S, Morokuma K. Why 11-cis-retinal? Why not 7-cis-, 9-cis-, or 13-cis-retinal in the eye? J Am Chem Soc 2011; 133:19052-5. [PMID: 22026715 DOI: 10.1021/ja208789h] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
One of the basic and unresolved puzzles in the chemistry of vision concerns the natural selection of 11-cis-retinal as the light-sensing chromophore in visual pigments. A detailed computational examination of the structure, stability, energetics, and spectroscopy of 7-cis-, 9-cis-, 11-cis-, and 13-cis-retinal isomers in vertebrate (bovine, monkey) and invertebrate (squid) visual pigments was carried out using a hybrid quantum mechanics/molecular mechanics (QM/MM) method. The results show that the electrostatic interaction between retinal and opsin dominates the natural selection of 11-cis-retinal over other cis isomers in the dark state. In all of the pigments, 9-cis-retinal was found to be only slightly higher in energy than 11-cis-retinal, which provides strong evidence for the presence of 9-cis-rhodopsin in nature. 7-cis-Retinal is suggested to be an "upside-down" version of the all-trans isomer because the structural rearrangements observed for 7-cis-rhodopsin from squid were found to be very similar to those for squid bathorhodopsin. The progressive red shift in the calculated absorption wavelength (λ(max)) (431, 456, 490, and 508 nm for the 7-cis-, 9-cis-, 11-cis-, and 13-cis-retinal isomers) is due to the decrease in bond length alternation of the retinal.
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Affiliation(s)
- Sivakumar Sekharan
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
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43
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Rajamani R, Lin YL, Gao J. The opsin shift and mechanism of spectral tuning in rhodopsin. J Comput Chem 2011; 32:854-65. [PMID: 20941732 PMCID: PMC3021771 DOI: 10.1002/jcc.21663] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 08/07/2010] [Indexed: 01/12/2023]
Abstract
Molecular dynamics simulations and combined quantum mechanical and molecular mechanical calculations have been performed to investigate the mechanism of the opsin shift and spectral tuning in rhodopsin. A red shift of -980 cm(-1) was estimated in the transfer of the chromophore from methanol solution environment to the protonated Schiff base (PSB)-binding site of the opsin. The conformational change from a 6-s-cis-all-trans configuration in solution to the 6-s-cis-11-cis conformer contributes additional -200 cm(-1), and the remaining effects were attributed to dispersion interactions with the aromatic residues in the binding site. An opsin shift of 2100 cm(-1) was obtained, in reasonable accord with experiment (2730 cm(-1)). Dynamics simulations revealed that the 6-s-cis bond can occupy two main conformations for the β-ionone ring, resulting in a weighted average dihedral angle of about -50°, which may be compared with the experimental estimate of -28° from solid-state NMR and Raman data. We investigated a series of four single mutations, including E113D, A292S, T118A, and A269T, which are located near the PSB, along the polyene chain of retinal and close to the ionone ring. The computational results on absorption energy shift provided insights into the mechanism of spectral tuning, which involves all means of electronic structural effects, including the stabilization or destabilization of either the ground or the electronically excited state of the retinal PSB.
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Affiliation(s)
| | - Yen-lin Lin
- Department of Chemistry, Digital Technology Center, and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455
| | - Jiali Gao
- Department of Chemistry, Digital Technology Center, and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455
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44
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Sekharan S, Morokuma K. QM/MM study of the structure, energy storage, and origin of the bathochromic shift in vertebrate and invertebrate bathorhodopsins. J Am Chem Soc 2011; 133:4734-7. [PMID: 21391708 PMCID: PMC3075117 DOI: 10.1021/ja200322w] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
By comparing the results from a hybrid quantum mechanics/molecular mechanics method (SORCI+Q//B3LYP/6-31G*:Amber) between vertebrate (bovine) and invertebrate (squid) visual pigments, the mechanism of molecular rearrangements, energy storage, and origin of the bathochromic shift accompanying the transformation of rhodopsin to bathorhodopsin have been evaluated. The analysis reveals that, in the presence of an unrelaxed binding site, bathorhodopsin was found to carry almost 27 kcal/mol energy in both visual pigments and absorb (λ(max)) at 528 nm in bovine and 554 nm in squid. However, when the residues within 4.0 Å radius of the retinal are relaxed during the isomerization event, almost ∼16 kcal/mol energy is lost in squid compared to only ∼8 kcal/mol in bovine. Loss of a larger amount of energy in squid is attributed to the presence of a flexible binding site compared to a rigid binding site in bovine. Structure of the squid bathorhodopsin is characterized by formation of a direct H-bond between the Schiff base and Asn87.
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45
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Frähmcke JS, Wanko M, Phatak P, Mroginski MA, Elstner M. The protonation state of Glu181 in rhodopsin revisited: interpretation of experimental data on the basis of QM/MM calculations. J Phys Chem B 2010; 114:11338-52. [PMID: 20698519 DOI: 10.1021/jp104537w] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The structure and spectroscopy of rhodopsin have been intensely studied in the past decade both experimentally and theoretically; however, important issues still remain unresolved. Of central interest is the protonation state of Glu181, where controversial and contradictory experimental evidence has appeared. While FTIR measurements indicate this residue to be unprotonated, preresonance Raman and UV-vis spectra have been interpreted in favor of a protonated Glu181. Previous computational approaches were not able to resolve this issue, providing contradicting data as well. Here, we perform hybrid QM/MM calculations using DFT methods for the electronic ground state, MRCI methods for the electronically excited states, and a polarization model for the MM part in order to investigate this issue systematically. We constructed various active-site models for protonated as well as unprotonated Glu181, which were evaluated by computing NMR, IR, Raman, and UV-vis spectroscopic data. The resulting differences in the UV-vis and Raman spectra between protonated and unprotonated models are very subtle, which has two major consequences. First, the common interpretation of prior Raman and UV-vis experiments in favor of a neutral Glu181 appears questionable, as it is based on the assumption that a charge at the Glu181 location would have a sizable impact. Second, also theoretical results should be interpreted with care. Spectroscopic differences between the structural models must be related to modeling uncertainties and intrinsic methodological errors. Despite a detailed comparison of various rhodopsins and mutants and consistently favorite results with charged Glu181 models, we find merely weak evidence from UV-vis and Raman calculations. On the contrary, difference FTIR and NMR chemical shift measurements on Rh mutants are indicative of the protonation state of Glu181. Supported by our results, they provide strong and independent evidence for a charged Glu181.
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Affiliation(s)
- Jan S Frähmcke
- Institute for Physical and Theoretical Chemistry, TU Braunschweig, Hans-Sommer-Str. 10, D-38106 Braunschweig, Germany
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46
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Sekharan S, Altun A, Morokuma K. QM/MM study of dehydro and dihydro β-ionone retinal analogues in squid and bovine rhodopsins: implications for vision in salamander rhodopsin. J Am Chem Soc 2010; 132:15856-9. [PMID: 20964383 DOI: 10.1021/ja105050p] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Visual pigment rhodopsin provides a decisive crossing point for interaction between organisms and environment. Naturally occurring visual pigments contain only PSB11 and 3,4-dehydro-PSB11 as chromophores. Therefore, the ability of visual opsin to discriminate between the retinal geometries is investigated by means of QM/MM incorporation of PSB11, 6-s-cis and 6-s-trans forms of 3,4-dehydro-PSB11, and 3,4-dehydro-5,6-dihydro-PSB11 and 5,6-dihydro-PSB11 analogues into squid and bovine rhodopsin environments. The analogue-protein interaction reveals the binding site of squid rhodopsin to be malleable and ductile, while that of bovine rhodopsin is rigid and stiff. On the basis of these studies, a tentative model of the salamander rhodopsin binding site is also proposed.
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Affiliation(s)
- Sivakumar Sekharan
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
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47
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Tsutsui K, Shichida Y. Multiple functions of Schiff base counterion in rhodopsins. Photochem Photobiol Sci 2010; 9:1426-34. [PMID: 20842311 DOI: 10.1039/c0pp00134a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In rhodopsins, visible-light absorption is achieved by the protonation of the chromophore Schiff base. The Schiff base proton is stabilized by the negative charge of an amino acid residue called the Schiff base counterion. Since E113 was identified as the counterion in bovine rhodopsin, there has been growing evidence that the counterion has multiple functions besides proton stabilization. Here, we first introduce generally accepted findings as well as some controversial theories about the identity of the Schiff base counterion in the dark and in intermediate states and then review multiple functions of the counterion in vertebrate visual pigments. Special focus is placed on the recently demonstrated role in photoisomerization efficiency. Finally, differences in the position of the counterion between vertebrate visual pigments and other opsins and its relevance to the molecular evolution of opsins are discussed.
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Affiliation(s)
- Kei Tsutsui
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
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48
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Ruckenbauer M, Barbatti M, Müller T, Lischka H. Nonadiabatic Excited-State Dynamics with Hybrid ab Initio Quantum-Mechanical/Molecular-Mechanical Methods: Solvation of the Pentadieniminium Cation in Apolar Media. J Phys Chem A 2010; 114:6757-65. [DOI: 10.1021/jp103101t] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matthias Ruckenbauer
- Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna, Austria, Institute of Advanced Simulation, Jülich Supercomputer Centre, Research Centre Jülich, D-52425 Jülich, Germany, and Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic
| | - Mario Barbatti
- Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna, Austria, Institute of Advanced Simulation, Jülich Supercomputer Centre, Research Centre Jülich, D-52425 Jülich, Germany, and Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic
| | - Thomas Müller
- Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna, Austria, Institute of Advanced Simulation, Jülich Supercomputer Centre, Research Centre Jülich, D-52425 Jülich, Germany, and Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic
| | - Hans Lischka
- Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna, Austria, Institute of Advanced Simulation, Jülich Supercomputer Centre, Research Centre Jülich, D-52425 Jülich, Germany, and Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic
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Lasogga L, Rettig W, Otto H, Wallat I, Bricks J. Model systems for the investigation of the opsin shift in bacteriorhodopsin. J Phys Chem A 2010; 114:2179-88. [PMID: 20085356 DOI: 10.1021/jp904132f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Donor-acceptor substituted styrenes and phenylbutadienes with substituents varying in donor and acceptor strength and as reconstituted chromophore-protein complexes were investigated as model compounds for the protonated Schiff base chromophore in bacteriorhodopsin (bR) both experimentally and theoretically. Charge distribution, donor-acceptor strength, and the shift of the absorption energy are correlated. The effect of the external electrostatic field was tested with a compound carrying an additional nonconjugated charge. The concept of overpolarization by the external charge, that is, the reversal of the relative importance of the two main resonance structures in S(0) and S(1), has been emphasized and related to a simple qualitative 2 x 2 interaction model. The variable donor approach is a new way for a better understanding of the Opsin shift in Bacteriorhodopsin.
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Affiliation(s)
- Lars Lasogga
- Institut für Chemie, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
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Sekharan S, Altun A, Morokuma K. Photochemistry of visual pigment in a G(q) protein-coupled receptor (GPCR)--insights from structural and spectral tuning studies on squid rhodopsin. Chemistry 2010; 16:1744-9. [PMID: 20066712 DOI: 10.1002/chem.200903194] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sivakumar Sekharan
- Department of Chemistry, Cherry L. Emerson Center for Scientific Computation, Emory University, 1515 Dickey Drive, Atlanta, GA 30322, USA
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