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Charette BJ, King SR, Chen J, Holm AR, Malme JT, Cook RD, Schaller RD, Jackson NE, Olshansky L. Excited State Dynamics of a Conformationally Fluxional Copper Coordination Complex. J Phys Chem A 2023; 127:7747-7755. [PMID: 37672011 DOI: 10.1021/acs.jpca.3c04269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
The conversion of solar energy into chemical fuel represents a capstone goal of the 21st century and has the potential to supply terawatts of power in a globally distributed manner. However, the disparate time scales of photodriven charge separation (∼fs) and steps in chemical reactions (∼μs) represent an inherent bottleneck in solar-to-fuels technology. To address this discrepancy, we are developing earth-abundant coordination complexes that undergo light-induced conformational rearrangements such that charge separation (CS) is hastened, while charge recombination (CR) is slowed. To these ends, we report the preparation and characterization of a new series of conformationally fluxional copper coordination complexes that contain a twisted intramolecular charge transfer (TICT) fluorophore as part of their ligand scaffold. Structural and spectroscopic characterization of the Cu(I) and Cu(II) complexes formed with these ligands in their ground states establish oxidation state-dependent conformational dynamicity, while time-resolved emission and transient absorption spectroscopies define the photophysical parameters of photo-induced excited states. Building on initial reports with a related set of molecules, the improved ligand design presented here greatly simplifies the observed photophysics, effectively shutting down unwanted ligand-centered excited states previously observed. Time-dependent density functional theory (TDDFT) analyses reveal an unusual metal-to-TICT electronic transition only reported once before, and though the formation of a CS state is not observed directly through experiments, TDDFT geometry optimizations in the excited states support the formation of transient Cu(II) CS species, lending credence to the potential success of our approach. These studies establish a clear model for the excited state dynamics at play in proof-of-concept systems and clarify key design parameters for future optimizations toward achieving long-lived CS via photoinduced conformational gating.
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Affiliation(s)
- Bronte J Charette
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Shelby R King
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Jiaqi Chen
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Annika R Holm
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Justin T Malme
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Robert D Cook
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Richard D Schaller
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Nicholas E Jackson
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Lisa Olshansky
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
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Fatima S, Boggs DG, Ali N, Thompson PJ, Thielges MC, Bridwell-Rabb J, Olshansky L. Engineering a Conformationally Switchable Artificial Metalloprotein. J Am Chem Soc 2022; 144:21606-21616. [DOI: 10.1021/jacs.2c08885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Saman Fatima
- Department of Chemistry, University of Illinois Urbana−Champaign, 600 S. Mathews Avenue, Urbana, Illinois61801, United States
| | - David G. Boggs
- Department of Chemistry, University of Michigan, 930 N. University Avenue, Ann Arbor, Michigan48109, United States
| | - Noor Ali
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana47405, United States
| | - Peter J. Thompson
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana−Champaign, 600 S. Mathews Avenue, Urbana, Illinois61801, United States
| | - Megan C. Thielges
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana47405, United States
| | - Jennifer Bridwell-Rabb
- Department of Chemistry, University of Michigan, 930 N. University Avenue, Ann Arbor, Michigan48109, United States
| | - Lisa Olshansky
- Department of Chemistry, University of Illinois Urbana−Champaign, 600 S. Mathews Avenue, Urbana, Illinois61801, United States
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana−Champaign, 600 S. Mathews Avenue, Urbana, Illinois61801, United States
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Golub M, Moldenhauer M, Schmitt FJ, Lohstroh W, Maksimov EG, Friedrich T, Pieper J. Solution Structure and Conformational Flexibility in the Active State of the Orange Carotenoid Protein. Part II: Quasielastic Neutron Scattering. J Phys Chem B 2019; 123:9536-9545. [PMID: 31550157 DOI: 10.1021/acs.jpcb.9b05073] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Orange carotenoid proteins (OCPs), which are protecting cyanobacterial light-harvesting antennae from photodamage, undergo a pronounced structural change upon light absorption. In addition, the active state is anticipated to boost a significantly higher molecular flexibility similar to a "molten globule" state. Here, we used quasielastic neutron scattering to directly characterize the vibrational and conformational molecular dynamics of OCP in its ground and active states, respectively, on the picosecond time scale. At a temperature of 100 K, we observe mainly (vibronic) inelastic features with peak energies at 5 and 6 meV (40 and 48 cm-1, respectively). At physiological temperatures, however, two (Lorentzian) quasielastic components represent localized protein motions, that is, stochastic structural fluctuations of protein side chains between various conformational substates of the protein. Global diffusion of OCP is not observed on the given time scale. The slower Lorentzian component is affected by illumination and can be well-characterized by a jump-diffusion model. While the jump diffusion constant D is (2.82 ± 0.01) × 10-5 cm2/s at 300 K in the ground state, it is increased by ∼20% to (3.48 ± 0.01) × 10-5 cm2/s in the active state, revealing a strong enhancement of molecular mobility. The increased mobility is also reflected in the average atomic mean square displacement ⟨u2⟩; we determine a ⟨u2⟩ of 1.47 ± 0.05 Å in the ground state, but 1.86 ± 0.05 Å in the active state (at 300 K). This effect is assigned to two factors: (i) the elongated structure of the active state with two widely separated protein domains is characterized by a larger number of surface residues with a concomitantly higher degree of motional freedom and (ii) a larger number of hydration water molecules bound at the surface of the protein. We thus conclude that the active state of the orange carotenoid protein displays an enhanced conformational dynamics. The higher degree of flexibility may provide additional channels for nonradiative decay so that harmful excess energy can be more efficiently converted to heat.
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Affiliation(s)
- Maksym Golub
- Institute of Physics , University of Tartu , 50411 Tartu , Estonia
| | - Marcus Moldenhauer
- Technische Universität Berlin , Institute of Chemistry, Physical Chemistry , 10623 Berlin , Germany
| | - Franz-Josef Schmitt
- Technische Universität Berlin , Institute of Chemistry, Physical Chemistry , 10623 Berlin , Germany
| | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum , Technische Universität München , Garching , Germany
| | - Eugene G Maksimov
- Department of Biophysics , M. V. Lomonosov Moscow State University , Moscow , Russia
| | - Thomas Friedrich
- Technische Universität Berlin , Institute of Chemistry, Physical Chemistry , 10623 Berlin , Germany
| | - Jörg Pieper
- Institute of Physics , University of Tartu , 50411 Tartu , Estonia
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Kaftan D, Bína D, Koblížek M. Temperature dependence of photosynthetic reaction centre activity in Rhodospirillum rubrum. PHOTOSYNTHESIS RESEARCH 2019; 142:181-193. [PMID: 31267356 PMCID: PMC6848049 DOI: 10.1007/s11120-019-00652-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/03/2019] [Indexed: 06/09/2023]
Abstract
The influence of temperature on photosynthetic reactions was investigated by a combination of time-resolved bacteriochlorophyll fluorescence, steady-state and differential absorption spectroscopy, and polarographic respiration measurements in intact cells of purple non-sulphur bacterium Rhodospirillum rubrum. Using variable bacteriochlorophyll fluorescence, it was found that the electron-transport activity increased with the increasing temperature up to 41 °C. The fast and medium components of the fluorescence decay kinetics followed the ideal Arrhenius equation. The calculated activation energy for the fast component was Ea1 = 16 kJ mol-1, while that of the medium component was more than double, with Ea2 = 38 kJ mol-1. At temperatures between 41 and 59 °C, the electron transport was gradually, irreversibly inhibited. Interestingly, the primary charge separation remained fully competent from 20 to 59 °C as documented by both BChl fluorescence and differential absorption spectroscopy of the P870+ signal. At temperatures above 60 °C, the primary photochemistry became reversibly inhibited, which was manifested by an increase in minimal fluorescence, F0, whereas maximal fluorescence, FM, slowly declined. Finally, above 71 °C, the photosynthetic complexes began to disassemble as seen in the decline of all fluorometric parameters and the disappearance of the LH1 absorption band at 880 nm. The extended optimal temperature of photosynthetic reaction centre in a model species of Rhodospirillales adds on the evidence that the good thermostability of the photosynthetic reaction centres is present across all Alphaproteobacteria.
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Affiliation(s)
- David Kaftan
- Center Algatech, Institute of Microbiology CAS, 37981, Třeboň, Czech Republic.
- Faculty of Science, University of South Bohemia, 37005, Ceske Budejovice, Czech Republic.
| | - David Bína
- Faculty of Science, University of South Bohemia, 37005, Ceske Budejovice, Czech Republic
- Biology Centre, Czech Academy of Sciences, Branišovská 31, Ceske Budejovice, Czech Republic
| | - Michal Koblížek
- Center Algatech, Institute of Microbiology CAS, 37981, Třeboň, Czech Republic
- Faculty of Science, University of South Bohemia, 37005, Ceske Budejovice, Czech Republic
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Dynamics Properties of Photosynthetic Microorganisms Probed by Incoherent Neutron Scattering. Biophys J 2019; 116:1759-1768. [PMID: 31003761 DOI: 10.1016/j.bpj.2019.03.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/18/2019] [Accepted: 03/20/2019] [Indexed: 01/06/2023] Open
Abstract
Studies on the dynamical properties of photosynthetic membranes of land plants and purple bacteria have been previously performed by neutron spectroscopy, revealing a tight coupling between specific photochemical reactions and macromolecular dynamics. Here, we probed the intrinsic dynamics of biotechnologically useful mutants of the green alga Chlamydomonas reinhardtii by incoherent neutron scattering coupled with prompt chlorophyll fluorescence experiments. We brought to light that single amino acid replacements in the plastoquinone (PQ)-binding niche of the photosystem II D1 protein impair electron transport (ET) efficiency between quinones and confer increased flexibility to the host membranes, expanding to the entire cells. Hence, a more flexible environment in the PQ-binding niche has been associated to a less efficient ET. A similar function/dynamics relationship was also demonstrated in Rhodobacter sphaeroides reaction centers having inhibited ET, indicating that flexibility at the quinones region plays a crucial role in evolutionarily distant organisms. Instead, a different functional/dynamical correlation was observed in algal mutants hosting a single amino acid replacement residing in a D1 domain far from the PQ-binding niche. Noteworthy, this mutant displayed the highest degree of flexibility, and besides having a nativelike ET efficiency in physiological conditions, it acquired novel, to our knowledge, phenotypic traits enabling it to preserve a high maximal quantum yield of photosystem II photochemistry in extreme habitats. Overall, in the nanosecond timescale, the degree of the observed flexibility is related to the mutation site; in the picosecond timescale, we highlighted the presence of a more pronounced dynamic heterogeneity in all mutants compared to the native cells, which could be related to a marked chemically heterogeneous environment.
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Antonacci A, Lambreva MD, Margonelli A, Sobolev AP, Pastorelli S, Bertalan I, Johanningmeier U, Sobolev V, Samish I, Edelman M, Havurinne V, Tyystjärvi E, Giardi MT, Mattoo AK, Rea G. Photosystem-II D1 protein mutants of Chlamydomonas reinhardtii in relation to metabolic rewiring and remodelling of H-bond network at Q B site. Sci Rep 2018; 8:14745. [PMID: 30283151 PMCID: PMC6170454 DOI: 10.1038/s41598-018-33146-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 09/21/2018] [Indexed: 12/21/2022] Open
Abstract
Photosystem II (PSII) reaction centre D1 protein of oxygenic phototrophs is pivotal for sustaining photosynthesis. Also, it is targeted by herbicides and herbicide-resistant weeds harbour single amino acid substitutions in D1. Conservation of D1 primary structure is seminal in the photosynthetic performance in many diverse species. In this study, we analysed built-in and environmentally-induced (high temperature and high photon fluency – HT/HL) phenotypes of two D1 mutants of Chlamydomonas reinhardtii with Ala250Arg (A250R) and Ser264Lys (S264K) substitutions. Both mutations differentially affected efficiency of electron transport and oxygen production. In addition, targeted metabolomics revealed that the mutants undergo specific differences in primary and secondary metabolism, namely, amino acids, organic acids, pigments, NAD, xanthophylls and carotenes. Levels of lutein, β-carotene and zeaxanthin were in sync with their corresponding gene transcripts in response to HT/HL stress treatment in the parental (IL) and A250R strains. D1 structure analysis indicated that, among other effects, remodelling of H-bond network at the QB site might underpin the observed phenotypes. Thus, the D1 protein, in addition to being pivotal for efficient photosynthesis, may have a moonlighting role in rewiring of specific metabolic pathways, possibly involving retrograde signalling.
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Affiliation(s)
- Amina Antonacci
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29,3 00015, Monterotondo Stazione, Rome, Italy
| | - Maya D Lambreva
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29,3 00015, Monterotondo Stazione, Rome, Italy
| | - Andrea Margonelli
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29,3 00015, Monterotondo Stazione, Rome, Italy
| | - Anatoly P Sobolev
- Institute of Chemical Methodologies, National Research Council of Italy, Via Salaria km 29,3 00015, Monterotondo Stazione, Rome, Italy
| | - Sandro Pastorelli
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29,3 00015, Monterotondo Stazione, Rome, Italy.,Neotron S.p.a., Santa Maria di Mugnano, Modena, Italy
| | - Ivo Bertalan
- Martin-Luther-University, Plant Physiology Institute, Weinbergweg 10, D-06120, Halle Saale, Germany
| | - Udo Johanningmeier
- Martin-Luther-University, Plant Physiology Institute, Weinbergweg 10, D-06120, Halle Saale, Germany
| | - Vladimir Sobolev
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Ilan Samish
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel.,Amai Proteins Ltd., 2 Bergman St., Rehovot, Israel
| | - Marvin Edelman
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Vesa Havurinne
- Department of Biochemistry/Molecular Plant Biology, FI-20014, University of Turku, Turku, Finland
| | - Esa Tyystjärvi
- Department of Biochemistry/Molecular Plant Biology, FI-20014, University of Turku, Turku, Finland
| | - Maria T Giardi
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29,3 00015, Monterotondo Stazione, Rome, Italy
| | - Autar K Mattoo
- The Henry A Wallace Beltsville Agricultural Research Centre, United States Department of Agriculture, Sustainable Agricultural Systems Laboratory, Beltsville, Maryland, 20705, USA.
| | - Giuseppina Rea
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29,3 00015, Monterotondo Stazione, Rome, Italy.
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Golub M, Rusevich L, Irrgang KD, Pieper J. Rigid versus Flexible Protein Matrix: Light-Harvesting Complex II Exhibits a Temperature-Dependent Phonon Spectral Density. J Phys Chem B 2018; 122:7111-7121. [DOI: 10.1021/acs.jpcb.8b02948] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maksym Golub
- Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu, Estonia
| | - Leonid Rusevich
- Institute of Physical Energetics, Krivu 11, LV-1006 Riga, Latvia
- Institute of Solid State Physics, University of Latvia, Kengaraga 8, LV-1063 Riga, Latvia
| | - Klaus-Dieter Irrgang
- Department of Life Science & Technology, Laboratory of Biochemistry, University for Applied Sciences, 10318 Berlin, Germany
| | - Jörg Pieper
- Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu, Estonia
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Sipka G, Kis M, Maróti P. Characterization of mercury(II)-induced inhibition of photochemistry in the reaction center of photosynthetic bacteria. PHOTOSYNTHESIS RESEARCH 2018; 136:379-392. [PMID: 29285578 DOI: 10.1007/s11120-017-0474-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/20/2017] [Indexed: 06/07/2023]
Abstract
Mercuric contamination of aqueous cultures results in impairment of viability of photosynthetic bacteria primarily by inhibition of the photochemistry of the reaction center (RC) protein. Isolated reaction centers (RCs) from Rhodobacter sphaeroides were exposed to Hg2+ ions up to saturation concentration (~ 103 [Hg2+]/[RC]) and the gradual time- and concentration-dependent loss of the photochemical activity was monitored. The vast majority of Hg2+ ions (about 500 [Hg2+]/[RC]) had low affinity for the RC [binding constant Kb ~ 5 mM-1] and only a few (~ 1 [Hg2+]/[RC]) exhibited strong binding (Kb ~ 50 μM-1). Neither type of binding site had specific and harmful effects on the photochemistry of the RC. The primary charge separation was preserved even at saturation mercury(II) concentration, but essential further steps of stabilization and utilization were blocked already in the 5 < [Hg2+]/[RC] < 50 range whose locations were revealed. (1) The proton gate at the cytoplasmic site had the highest affinity for Hg2+ binding (Kb ~ 0.2 μM-1) and blocked the proton uptake. (2) Reduced affinity (Kb ~ 0.05 μM-1) was measured for the mercury(II)-binding site close to the secondary quinone that resulted in inhibition of the interquinone electron transfer. (3) A similar affinity was observed close to the bacteriochlorophyll dimer causing slight energetic changes as evidenced by a ~ 30 nm blue shift of the red absorption band, a 47 meV increase in the redox midpoint potential, and a ~ 20 meV drop in free energy gap of the primary charge pair. The primary quinone was not perturbed upon mercury(II) treatment. Although the Hg2+ ions attack the RC in large number, the exertion of the harmful effect on photochemistry is not through mass action but rather a couple of well-defined targets. Bound to these sites, the Hg2+ ions can destroy H-bond structures, inhibit protein dynamics, block conformational gating mechanisms, and modify electrostatic profiles essential for electron and proton transfer.
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Affiliation(s)
- Gábor Sipka
- Department of Medical Physics, University of Szeged, Rerrich Béla tér 1, Szeged, 6720, Hungary
- Department of Plant Biology, Hungarian Academy of Science, Biological Research Centre, Szeged, Hungary
| | - Mariann Kis
- Department of Medical Physics, University of Szeged, Rerrich Béla tér 1, Szeged, 6720, Hungary
| | - Péter Maróti
- Department of Medical Physics, University of Szeged, Rerrich Béla tér 1, Szeged, 6720, Hungary.
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