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Gisriel CJ, Flesher DA, Long Z, Liu J, Wang J, Bryant DA, Batista VS, Brudvig GW. A quantitative assessment of (bacterio)chlorophyll assignments in the cryo-EM structure of the Chloracidobacterium thermophilum reaction center. PHOTOSYNTHESIS RESEARCH 2023:10.1007/s11120-023-01047-5. [PMID: 37749456 DOI: 10.1007/s11120-023-01047-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/31/2023] [Indexed: 09/27/2023]
Abstract
Chlorophylls and bacteriochlorophylls are the primary pigments used by photosynthetic organisms for light harvesting, energy transfer, and electron transfer. Many molecular structures of (bacterio)chlorophyll-containing protein complexes are available, some of which contain mixtures of different (bacterio)chlorophyll types. Differentiating these, which sometimes are structurally similar, is challenging but is required for leveraging structural data to gain functional insight. The reaction center complex from Chloroacidobacterium thermophilum has a hybrid (bacterio)chlorophyll antenna system containing both chlorophyll a and bacteriochlorophyll a molecules. The recent availability of its cryogenic electron microscopy (cryo-EM) structure provides an opportunity for a quantitative analysis of their identities and chemical environments. Here, we describe a theoretical basis for differentiating chlorophyll a and bacteriochlorophyll a in a cryo-EM map, and apply the approach to the experimental cryo-EM maps of the (bacterio)chlorophyll sites of the chloroacidobacterial reaction center. The comparison reveals that at ~ 2.2-Å resolution, chlorophyll a and bacteriochlorophyll a are easily distinguishable, but the orientation of the bacteriochlorophyll a acetyl moiety is not; however, the latter can confidently be assigned by identifying a hydrogen bond donor from the protein environment. This study reveals the opportunities and challenges in assigning (bacterio)chlorophyll types in structural biology, the accuracy of which is vital for downstream investigations.
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Affiliation(s)
| | - David A Flesher
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Zhuoran Long
- Department of Chemistry, Yale University, New Haven, CT, 06520, USA
| | - Jinchan Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Jimin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Victor S Batista
- Department of Chemistry, Yale University, New Haven, CT, 06520, USA
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, CT, 06520, USA.
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA.
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2
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Kurle-Tucholski P, Köhler L, Zhao Z, Link G, Wiebeler C, Matysik J. Stabilization of a flavoprotein for solid-state photo-CIDNP MAS NMR at room temperature by embedding in a glassy sugar matrix. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 353:107497. [PMID: 37295281 DOI: 10.1016/j.jmr.2023.107497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/26/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023]
Abstract
Hyperpolarization via the solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect can be detected in frozen solutions of electron transfer proteins generating a radical-pair upon illumination. The effect has been observed in various natural photosynthetic reaction centers and in light-oxygen-voltage (LOV) sensing domains incorporating a flavin mononucleotide (FMN) as chromophore. In LOV domains, where a highly conserved cysteine is mutated to a flavin to interrupt its natural photochemistry, a radical-pair is generated by electron transfer from a nearby tryptophan to the photoexcited triplet state of FMN. During the photocycle, both the LOV domain and the chromophore are photochemically degraded, e.g., by the formation of singlet oxygen. This limits the time for collection of hyperpolarized nuclear magnetic resonance (NMR) data. We show that embedding of the protein into a trehalose sugar glass matrix stabilizes the protein for 13C solid-state photo-CIDNP NMR experiments which can be conducted at room temperature in a powder sample. Additionally, this preparation allows for incorporation of high amounts of protein further boosting the intensity of the detected signals from FMN and tryptophan at natural abundance. Signal assignment is aided by quantum chemical calculations of absolute shieldings. The underlying mechanism for the surprising absorption-only signal pattern is not yet understood. Comparison to calculated isotropic hyperfine couplings imply that the enhancement is not due to the classical radical-pair mechanism (RPM). Analysis of the anisotropic hyperfine couplings associated with solid-state photo-CIDNP mechanisms also show no simple correlation, suggesting a more complex underlying mechanism.
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Affiliation(s)
- Patrick Kurle-Tucholski
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Lisa Köhler
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Ziyue Zhao
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Gerhard Link
- Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 21, D-79104 Freiburg, Germany
| | - Christian Wiebeler
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany; Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Linnéstraße 2, D-04103 Leipzig, Germany; Institut für Physik, Universität Augsburg, Universitätsstraße 1, D-86159 Augsburg, Germany
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany.
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Structure of the Acidobacteria homodimeric reaction center bound with cytochrome c. Nat Commun 2022; 13:7745. [PMID: 36517472 PMCID: PMC9751088 DOI: 10.1038/s41467-022-35460-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
Photosynthesis converts light energy to chemical energy to fuel life on earth. Light energy is harvested by antenna pigments and transferred to reaction centers (RCs) to drive the electron transfer (ET) reactions. Here, we present cryo-electron microscopy (cryo-EM) structures of two forms of the RC from the microaerophilic Chloracidobacterium thermophilum (CabRC): one containing 10 subunits, including two different cytochromes; and the other possessing two additional subunits, PscB and PscZ. The larger form contained 2 Zn-bacteriochlorophylls, 16 bacteriochlorophylls, 10 chlorophylls, 2 lycopenes, 2 hemes, 3 Fe4S4 clusters, 12 lipids, 2 Ca2+ ions and 6 water molecules, revealing a type I RC with an ET chain involving two hemes and a hybrid antenna containing bacteriochlorophylls and chlorophylls. Our results provide a structural basis for understanding the excitation energy and ET within the CabRC and offer evolutionary insights into the origin and adaptation of photosynthetic RCs.
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Gisriel CJ, Azai C, Cardona T. Recent advances in the structural diversity of reaction centers. PHOTOSYNTHESIS RESEARCH 2021; 149:329-343. [PMID: 34173168 PMCID: PMC8452559 DOI: 10.1007/s11120-021-00857-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/10/2021] [Indexed: 06/13/2023]
Abstract
Photosynthetic reaction centers (RC) catalyze the conversion of light to chemical energy that supports life on Earth, but they exhibit substantial diversity among different phyla. This is exemplified in a recent structure of the RC from an anoxygenic green sulfur bacterium (GsbRC) which has characteristics that may challenge the canonical view of RC classification. The GsbRC structure is analyzed and compared with other RCs, and the observations reveal important but unstudied research directions that are vital for disentangling RC evolution and diversity. Namely, (1) common themes of electron donation implicate a Ca2+ site whose role is unknown; (2) a previously unidentified lipid molecule with unclear functional significance is involved in the axial ligation of a cofactor in the electron transfer chain; (3) the GsbRC features surprising structural similarities with the distantly-related photosystem II; and (4) a structural basis for energy quenching in the GsbRC can be gleaned that exemplifies the importance of how exposure to oxygen has shaped the evolution of RCs. The analysis highlights these novel avenues of research that are critical for revealing evolutionary relationships that underpin the great diversity observed in extant RCs.
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Affiliation(s)
| | - Chihiro Azai
- College of Life Sciences, Ritsumeikan University, Kusatsu, 525-8577, Japan
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, 525-8577, Japan
| | - Tanai Cardona
- Department of Life Sciences, Imperial College London, London, UK
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Saini MK, Sebastian A, Shirotori Y, Soulier NT, Garcia Costas AM, Drautz-Moses DI, Schuster SC, Albert I, Haruta S, Hanada S, Thiel V, Tank M, Bryant DA. Genomic and Phenotypic Characterization of Chloracidobacterium Isolates Provides Evidence for Multiple Species. Front Microbiol 2021; 12:704168. [PMID: 34220789 PMCID: PMC8245765 DOI: 10.3389/fmicb.2021.704168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 05/21/2021] [Indexed: 11/16/2022] Open
Abstract
Chloracidobacterium is the first and until now the sole genus in the phylum Acidobacteriota (formerly Acidobacteria) whose members perform chlorophyll-dependent phototrophy (i.e., chlorophototrophy). An axenic isolate of Chloracidobacterium thermophilum (strain B T ) was previously obtained by using the inferred genome sequence from an enrichment culture and diel metatranscriptomic profiling analyses in situ to direct adjustments to the growth medium and incubation conditions, and thereby a defined growth medium for Chloracidobacterium thermophilum was developed. These advances allowed eight additional strains of Chloracidobacterium spp. to be isolated from microbial mat samples collected from Mushroom Spring, Yellowstone National Park, United States, at temperatures of 41, 52, and 60°C; an axenic strain was also isolated from Rupite hot spring in Bulgaria. All isolates are obligately photoheterotrophic, microaerophilic, non-motile, thermophilic, rod-shaped bacteria. Chloracidobacterium spp. synthesize multiple types of (bacterio-)chlorophylls and have type-1 reaction centers like those of green sulfur bacteria. Light harvesting is accomplished by the bacteriochlorophyll a-binding, Fenna-Matthews-Olson protein and chlorosomes containing bacteriochlorophyll c. Their genomes are approximately 3.7 Mbp in size and comprise two circular chromosomes with sizes of approximately 2.7 Mbp and 1.0 Mbp. Comparative genomic studies and phenotypic properties indicate that the nine isolates represent three species within the genus Chloracidobacterium. In addition to C. thermophilum, the microbial mats at Mushroom Spring contain a second species, tentatively named Chloracidobacterium aggregatum, which grows as aggregates in liquid cultures. The Bulgarian isolate, tentatively named Chloracidobacterium validum, will be proposed as the type species of the genus, Chloracidobacterium. Additionally, Chloracidobacterium will be proposed as the type genus of a new family, Chloracidobacteriaceae, within the order Blastocatellales, the class Blastocatellia, and the phylum Acidobacteriota.
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Affiliation(s)
- Mohit Kumar Saini
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Japan
| | - Aswathy Sebastian
- The Huck Institutes for the Life Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Yoshiki Shirotori
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Japan
| | - Nathan T. Soulier
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Amaya M. Garcia Costas
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
- Department of Biology, Colorado State University-Pueblo, Pueblo, CO, United States
| | - Daniela I. Drautz-Moses
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Stephan C. Schuster
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Istvan Albert
- The Huck Institutes for the Life Sciences, The Pennsylvania State University, University Park, PA, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Shin Haruta
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Japan
| | - Satoshi Hanada
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Japan
| | - Vera Thiel
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Japan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
- DSMZ – German Culture Collection of Microorganisms and Cell Cultures, GmbH, Braunschweig, Germany
| | - Marcus Tank
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Japan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
- DSMZ – German Culture Collection of Microorganisms and Cell Cultures, GmbH, Braunschweig, Germany
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
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Abstract
Modified tetrapyrroles are large macrocyclic compounds, consisting of diverse conjugation and metal chelation systems and imparting an array of colors to the biological structures that contain them. Tetrapyrroles represent some of the most complex small molecules synthesized by cells and are involved in many essential processes that are fundamental to life on Earth, including photosynthesis, respiration, and catalysis. These molecules are all derived from a common template through a series of enzyme-mediated transformations that alter the oxidation state of the macrocycle and also modify its size, its side-chain composition, and the nature of the centrally chelated metal ion. The different modified tetrapyrroles include chlorophylls, hemes, siroheme, corrins (including vitamin B12), coenzyme F430, heme d1, and bilins. After nearly a century of study, almost all of the more than 90 different enzymes that synthesize this family of compounds are now known, and expression of reconstructed operons in heterologous hosts has confirmed that most pathways are complete. Aside from the highly diverse nature of the chemical reactions catalyzed, an interesting aspect of comparative biochemistry is to see how different enzymes and even entire pathways have evolved to perform alternative chemical reactions to produce the same end products in the presence and absence of oxygen. Although there is still much to learn, our current understanding of tetrapyrrole biogenesis represents a remarkable biochemical milestone that is summarized in this review.
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Affiliation(s)
- Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, United Kingdom
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Charles P, Kalendra V, He Z, Khatami MH, Golbeck JH, van der Est A, Lakshmi KV, Bryant DA. Two-dimensional 67Zn HYSCORE spectroscopy reveals that a Zn-bacteriochlorophyll aP′ dimer is the primary donor (P840) in the type-1 reaction centers of Chloracidobacterium thermophilum. Phys Chem Chem Phys 2020; 22:6457-6467. [DOI: 10.1039/c9cp06556c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Using pulsed EPR spectroscopy and isotopic labeling we demonstrate that reaction centers of Chloracidobacterium thermophilum have an unusual primary donor that is a dimer of Zn-bacteriochlorophyll aP′ molecules.
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Affiliation(s)
- Philip Charles
- Departments of Chemistry and Physics and The Baruch ’60 Center for Biochemical Solar Energy Research
- Rensselaer Polytechnic Institute
- Troy
- USA
| | - Vidmantas Kalendra
- Departments of Chemistry and Physics and The Baruch ’60 Center for Biochemical Solar Energy Research
- Rensselaer Polytechnic Institute
- Troy
- USA
| | - Zhihui He
- Department of Biochemistry and Molecular Biology
- The Pennsylvania State University
- State College
- USA
| | | | - John H. Golbeck
- Department of Biochemistry and Molecular Biology
- The Pennsylvania State University
- State College
- USA
- Department of Chemistry
| | | | - K. V. Lakshmi
- Departments of Chemistry and Physics and The Baruch ’60 Center for Biochemical Solar Energy Research
- Rensselaer Polytechnic Institute
- Troy
- USA
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology
- The Pennsylvania State University
- State College
- USA
- Department of Chemistry and Biochemistry
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8
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Tamiaki H, Fukai K, Nakamura S. Intramolecular interaction of synthetic chlorophyll heterodyads with different π-skeletons. Photochem Photobiol Sci 2020; 19:332-340. [DOI: 10.1039/c9pp00373h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Covalently linked zinc chlorin and zinc porphyrin/bacteriochlorin heterodyads formed methanol-locked conformers with red-shifted Qy bands as models of Chl-a and Chl-c/BChl-a(or g) dimeric species, respectively, in photosynthetic apparatuses.
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Affiliation(s)
- Hitoshi Tamiaki
- Graduate School of Life Sciences
- Ritsumeikan University
- Kusatsu
- Japan
| | - Kazuhiro Fukai
- Graduate School of Life Sciences
- Ritsumeikan University
- Kusatsu
- Japan
| | - Soichi Nakamura
- Graduate School of Life Sciences
- Ritsumeikan University
- Kusatsu
- Japan
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9
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Ding Y, Kiryutin AS, Yurkovskaya AV, Sosnovsky DV, Sagdeev RZ, Bannister S, Kottke T, Kar RK, Schapiro I, Ivanov KL, Matysik J. Nuclear spin-hyperpolarization generated in a flavoprotein under illumination: experimental field-dependence and theoretical level crossing analysis. Sci Rep 2019; 9:18436. [PMID: 31804538 PMCID: PMC6895156 DOI: 10.1038/s41598-019-54671-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/15/2019] [Indexed: 11/25/2022] Open
Abstract
The solid-state photo-chemically induced dynamic nuclear polarization (photo-CIDNP) effect generates non-equilibrium nuclear spin polarization in frozen electron-transfer proteins upon illumination and radical-pair formation. The effect can be observed in various natural photosynthetic reaction center proteins using magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, and in a flavin-binding light-oxygen-voltage (LOV) domain of the blue-light receptor phototropin. In the latter system, a functionally instrumental cysteine has been mutated to interrupt the natural cysteine-involving photochemistry allowing for an electron transfer from a more distant tryptophan to the excited flavin mononucleotide chromophore. We explored the solid-state photo-CIDNP effect and its mechanisms in phototropin-LOV1-C57S from the green alga Chlamydomonas reinhardtii by using field-cycling solution NMR. We observed the 13C and, to our knowledge, for the first time, 15N photo-CIDNP signals from phototropin-LOV1-C57S. Additionally, the 1H photo-CIDNP signals of residual water in the deuterated buffer of the protein were detected. The relative strengths of the photo-CIDNP effect from the three types of nuclei, 1H, 13C and 15N were measured in dependence of the magnetic field, showing their maximum polarizations at different magnetic fields. Theoretical level crossing analysis demonstrates that anisotropic mechanisms play the dominant role at high magnetic fields.
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Affiliation(s)
- Yonghong Ding
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany
| | - Alexey S Kiryutin
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Alexandra V Yurkovskaya
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Denis V Sosnovsky
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Renad Z Sagdeev
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Saskia Bannister
- Physical and Biophysical Chemistry, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Tilman Kottke
- Physical and Biophysical Chemistry, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Rajiv K Kar
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Konstantin L Ivanov
- International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya, 3а, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 1, Novosibirsk, 630090, Russia
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103, Leipzig, Germany.
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Paul S, Roy U, Böckers M, Neugebauer J, Alia A, Matysik J. 15N photo-CIDNP MAS NMR analysis of a bacterial photosynthetic reaction center of Rhodobacter sphaeroides wildtype. J Chem Phys 2019; 151:195101. [PMID: 31757137 DOI: 10.1063/1.5128783] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect has been studied in a quinone-depleted uniformly (u-)13C,15N-labeled photosynthetic reaction center (RC) protein from purple bacterium Rhodobacter (R.) sphaeroides wild type (WT). As a method for investigation, solid-state 15N NMR under magic-angle spinning (MAS) is applied under both continuous illumination (steady state) and nanosecond-laser flashes (time-resolved). While all previous 15N photo-CIDNP MAS NMR studies on the purple bacterial RC used the carotenoid-less mutant R26, this is the first using WT samples. The absence of further photo-CIDNP mechanisms (compared to R26) and various couplings (compared to 13C NMR experiments on 13C-labeled samples) allows the simplification of the spin-system. We report 15N signals of the three cofactors forming the spin-correlated radical pair (SCRP) and, based on density-functional theory calculations, their assignment. The simulation of photo-CIDNP intensities and time-resolved 15N photo-CIDNP MAS NMR data matches well to the frame of the mechanistic interpretation. Three spin-chemical processes, namely, radical pair mechanism, three spin mixing, and differential decay, generate emissive (negative) 15N polarization in the singlet decay channel and absorptive (positive) polarization in the triplet decay channel of the SCRP. The absorptive 15N polarization of the triplet decay channel is transiently obscured during the lifetime of the triplet state of the carotenoid (3Car); therefore, the observed 15N signals are strongly emissive. Upon decay of 3Car, the transiently obscured polarization becomes visible by reducing the excess of emissive polarization. After the decline of 3Car, the remaining nuclear hyperpolarization decays with nuclear T1 relaxation kinetics.
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Affiliation(s)
- Shubhajit Paul
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, D-04103 Leipzig, Germany
| | - Upasana Roy
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, D-04103 Leipzig, Germany
| | - Michael Böckers
- Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Universität Münster, Corrensstraße 40, D-48149 Münster, Germany
| | - Johannes Neugebauer
- Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Universität Münster, Corrensstraße 40, D-48149 Münster, Germany
| | - A Alia
- Institut für Medizinische Physik und Biophysik, Universität Leipzig, Härtelstr. 16, D-04107 Leipzig, Germany
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, D-04103 Leipzig, Germany
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11
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He Z, Ferlez B, Kurashov V, Tank M, Golbeck JH, Bryant DA. Reaction centers of the thermophilic microaerophile, Chloracidobacterium thermophilum (Acidobacteria) I: biochemical and biophysical characterization. PHOTOSYNTHESIS RESEARCH 2019; 142:87-103. [PMID: 31161318 DOI: 10.1007/s11120-019-00650-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 05/27/2019] [Indexed: 06/09/2023]
Abstract
Chloracidobacterium thermophilum is a microaerophilic, anoxygenic member of the green chlorophototrophic bacteria. This bacterium is the first characterized oxygen-requiring chlorophototroph with chlorosomes, the FMO protein, and homodimeric type-1 reaction centers (RCs). The RCs of C. thermophilum are also unique because they contain three types of chlorophylls, bacteriochlorophyll aP esterified with phytol, Chl aPD esterified with Δ2,6-phytadienol, and Zn-BChl aP' esterified with phytol, in the approximate molar ratio 32:24:4. The light-induced difference spectrum of these RCs had a bleaching maximum at 839 nm and also revealed an electrochromic bandshift that is probably derived from a BChl a molecule near P840+. The FX [4Fe-4S] cluster had a midpoint potential of ca. - 581 mV, and the spectroscopic properties of the P+ F X - spin-polarized radical pair were very similar to those of reaction centers of heliobacteria and green sulfur bacteria. The data further indicate that electron transfer occurs directly from A0- to FX, as occurs in other homodimeric type-1 RCs. Washing experiments with isolated membranes suggested that the PscB subunit of these reaction centers is more tightly bound than PshB in heliobacteria. Thus, the reaction centers of C. thermophilum have some properties that resemble other homodimeric reaction centers but also have specific properties that are more similar to those of Photosystem I. These differences probably contribute to protection of the electron transfer chain from oxygen, contributing to the oxygen tolerance of this microaerophile.
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Affiliation(s)
- Zhihui He
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
| | - Bryan Ferlez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
- MSU-DOE Plant Research Laboratory, Michigan State University, 612 Wilson Road, East Lansing, MI, 48824, USA
| | - Vasily Kurashov
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
| | - Marcus Tank
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
- Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo, 192-0397, Japan
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA.
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA.
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Studying hydrogen bonding and dynamics of the acetylate groups of the Special Pair of Rhodobacter sphaeroides WT. Sci Rep 2019; 9:10528. [PMID: 31324886 PMCID: PMC6642110 DOI: 10.1038/s41598-019-46903-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/08/2019] [Indexed: 11/17/2022] Open
Abstract
Although the cofactors in the bacterial reaction centre of Rhodobacter sphaeroides wild type (WT) are arranged almost symmetrically in two branches, the light-induced electron transfer occurs selectively in one branch. As origin of this functional symmetry break, a hydrogen bond between the acetyl group of PL in the primary donor and His-L168 has been discussed. In this study, we investigate the existence and rigidity of this hydrogen bond with solid-state photo-CIDNP MAS NMR methods offering information on the local electronic structure due to highly sensitive and selective NMR experiments. On the time scale of the experiment, the hydrogen bond between PL and His-L168 appears to be stable and not to be affected by illumination confirming a structural asymmetry within the Special Pair.
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Hastings G, Makita H, Agarwala N, Rohani L, Shen G, Bryant DA. Fourier transform visible and infrared difference spectroscopy for the study of P700 in photosystem I from Fischerella thermalis PCC 7521 cells grown under white light and far-red light: Evidence that the A–1 cofactor is chlorophyll f. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:452-460. [DOI: 10.1016/j.bbabio.2019.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 10/27/2022]
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Bielytskyi P, Gräsing D, Zahn S, Mote KR, Alia A, Madhu PK, Matysik J. Assignment of NMR resonances of protons covalently bound to photochemically active cofactors in photosynthetic reaction centers by 13C- 1H photo-CIDNP MAS-J-HMQC experiment. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 298:64-76. [PMID: 30529893 DOI: 10.1016/j.jmr.2018.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 06/09/2023]
Abstract
Modified versions of through-bond heteronuclear correlation (HETCOR) experiments are presented to take advantage of the light-induced hyperpolarization that occurs on 13C nuclei due to the solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect. Such 13C-1H photo-CIDNP MAS-J-HMQC and photo-CIDNP MAS-J-HSQC experiments are applied to acquire the 2D 13C-1H correlation spectra of selectively 13C-labeled photochemically active cofactors in the frozen quinone-blocked photosynthetic reaction center (RC) of the purple bacterium Rhodobacter (R.) sphaeroides wild-type (WT). Resulting spectra contain no correlation peaks arising from the protein backbone, which greatly simplifies the assignment of aliphatic region. Based on the photo-CIDNP MAS-J-HMQC NMR experiment, we obtained assignment of selective 1H NMR resonances of the cofactors involved in the electron transfer process in the RC and compared them with values theoretically predicted by density functional theory (DFT) calculation as well as with the chemical shifts obtained from monomeric cofactors in the solution. We also compared proton chemical shifts obtained by photo-CIDNP MAS-J-HMQC experiment under continuous illumination with the ones obtained in dark by classical cross-polarization (CP) HETCOR. We expect that the proposed approach will become a method of choice for obtaining 1H chemical shift maps of the active cofactors in photosynthetic RCs and will aid the interpretation of heteronuclear spin-torch experiments.
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Affiliation(s)
- Pavlo Bielytskyi
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Daniel Gräsing
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany
| | - Stefan Zahn
- Leibniz Institute of Surface Engineering (IOM), Permoserstraße 15, D-04318 Leipzig, Germany
| | - Kaustubh R Mote
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 36/P Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad 500107, India
| | - A Alia
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2301 RA Leiden, the Netherlands; Institut für Medizinische Physik und Biophysik, Universität Leipzig, Härtelstr. 16-18, D-04107 Leipzig, Germany
| | - P K Madhu
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 36/P Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad 500107, India
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany.
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