1
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Vasilev C, Nguyen J, Bowie AGM, Mayneord GE, Martin EC, Hitchcock A, Pogorelov TV, Singharoy A, Hunter CN, Johnson MP. Single-Molecule Detection of the Encounter and Productive Electron Transfer Complexes of a Photosynthetic Reaction Center. J Am Chem Soc 2024; 146:20019-20032. [PMID: 38991108 PMCID: PMC11273609 DOI: 10.1021/jacs.4c03913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 07/02/2024] [Accepted: 07/03/2024] [Indexed: 07/13/2024]
Abstract
Small, diffusible redox proteins play an essential role in electron transfer (ET) in respiration and photosynthesis, sustaining life on Earth by shuttling electrons between membrane-bound complexes via finely tuned and reversible interactions. Ensemble kinetic studies show transient ET complexes form in two distinct stages: an "encounter" complex largely mediated by electrostatic interactions, which subsequently, through subtle reorganization of the binding interface, forms a "productive" ET complex stabilized by additional hydrophobic interactions around the redox-active cofactors. Here, using single-molecule force spectroscopy (SMFS) we dissected the transient ET complexes formed between the photosynthetic reaction center-light harvesting complex 1 (RC-LH1) of Rhodobacter sphaeroides and its native electron donor cytochrome c2 (cyt c2). Importantly, SMFS resolves the distribution of interaction forces into low (∼150 pN) and high (∼330 pN) components, with the former more susceptible to salt concentration and to alteration of key charged residues on the RC. Thus, the low force component is suggested to reflect the contribution of electrostatic interactions in forming the initial encounter complex, whereas the high force component reflects the additional stabilization provided by hydrophobic interactions to the productive ET complex. Employing molecular dynamics simulations, we resolve five intermediate states that comprise the encounter, productive ET and leaving complexes, predicting a weak interaction between cyt c2 and the LH1 ring near the RC-L subunit that could lie along the exit path for oxidized cyt c2. The multimodal nature of the interactions of ET complexes captured here may have wider implications for ET in all domains of life.
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Affiliation(s)
- Cvetelin Vasilev
- Plants,
Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
| | - Jon Nguyen
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
| | - Adam G. M. Bowie
- Plants,
Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
| | - Guy E. Mayneord
- Plants,
Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
| | - Elizabeth C. Martin
- Plants,
Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
| | - Andrew Hitchcock
- Plants,
Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
| | - Taras V. Pogorelov
- Department
of Chemistry, Center for Biophysics and Quantitative Biology, Beckman
Institute for Advanced Science and Technology, National Center for
Supercomputing Applications, School of Chemical Sciences, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Abhishek Singharoy
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
| | - C. Neil Hunter
- Plants,
Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
| | - Matthew P. Johnson
- Plants,
Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, U.K.
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2
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Martin EC, Bowie AG, Wellfare Reid T, Neil Hunter C, Hitchcock A, Swainsbury DJ. Sulfoquinovosyl diacylglycerol is required for dimerisation of the Rhodobacter sphaeroides reaction centre-light harvesting 1 core complex. Biochem J 2024; 481:823-838. [PMID: 38780411 PMCID: PMC11346425 DOI: 10.1042/bcj20240125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 05/25/2024]
Abstract
The reaction centre-light harvesting 1 (RC-LH1) core complex is indispensable for anoxygenic photosynthesis. In the purple bacterium Rhodobacter (Rba.) sphaeroides RC-LH1 is produced both as a monomer, in which 14 LH1 subunits form a C-shaped antenna around 1 RC, and as a dimer, where 28 LH1 subunits form an S-shaped antenna surrounding 2 RCs. Alongside the five RC and LH1 subunits, an additional polypeptide known as PufX provides an interface for dimerisation and also prevents LH1 ring closure, introducing a channel for quinone exchange that is essential for photoheterotrophic growth. Structures of Rba. sphaeroides RC-LH1 complexes revealed several new components; protein-Y, which helps to form the quinone channel; protein-Z, of unknown function and seemingly unique to dimers; and a tightly bound sulfoquinovosyl diacylglycerol (SQDG) lipid that interacts with two PufX arginine residues. This lipid lies at the dimer interface alongside weak density for a second molecule, previously proposed to be an ornithine lipid. In this work we have generated strains of Rba. sphaeroides lacking protein-Y, protein-Z, SQDG or ornithine lipids to assess the roles of these previously unknown components in the assembly and activity of RC-LH1. We show that whilst the removal of either protein-Y, protein-Z or ornithine lipids has only subtle effects, SQDG is essential for the formation of RC-LH1 dimers but its absence has no functional effect on the monomeric complex.
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Affiliation(s)
- Elizabeth C. Martin
- Plants, Photosynthesis and Soil, School of Bioscience, University of Sheffield, Sheffield, U.K
| | - Adam G.M. Bowie
- Plants, Photosynthesis and Soil, School of Bioscience, University of Sheffield, Sheffield, U.K
| | - Taylor Wellfare Reid
- Plants, Photosynthesis and Soil, School of Bioscience, University of Sheffield, Sheffield, U.K
| | - C. Neil Hunter
- Plants, Photosynthesis and Soil, School of Bioscience, University of Sheffield, Sheffield, U.K
| | - Andrew Hitchcock
- Plants, Photosynthesis and Soil, School of Bioscience, University of Sheffield, Sheffield, U.K
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3
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Ennist NM, Wang S, Kennedy MA, Curti M, Sutherland GA, Vasilev C, Redler RL, Maffeis V, Shareef S, Sica AV, Hua AS, Deshmukh AP, Moyer AP, Hicks DR, Swartz AZ, Cacho RA, Novy N, Bera AK, Kang A, Sankaran B, Johnson MP, Phadkule A, Reppert M, Ekiert D, Bhabha G, Stewart L, Caram JR, Stoddard BL, Romero E, Hunter CN, Baker D. De novo design of proteins housing excitonically coupled chlorophyll special pairs. Nat Chem Biol 2024; 20:906-915. [PMID: 38831036 PMCID: PMC11213709 DOI: 10.1038/s41589-024-01626-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 04/15/2024] [Indexed: 06/05/2024]
Abstract
Natural photosystems couple light harvesting to charge separation using a 'special pair' of chlorophyll molecules that accepts excitation energy from the antenna and initiates an electron-transfer cascade. To investigate the photophysics of special pairs independently of the complexities of native photosynthetic proteins, and as a first step toward creating synthetic photosystems for new energy conversion technologies, we designed C2-symmetric proteins that hold two chlorophyll molecules in closely juxtaposed arrangements. X-ray crystallography confirmed that one designed protein binds two chlorophylls in the same orientation as native special pairs, whereas a second designed protein positions them in a previously unseen geometry. Spectroscopy revealed that the chlorophylls are excitonically coupled, and fluorescence lifetime imaging demonstrated energy transfer. The cryo-electron microscopy structure of a designed 24-chlorophyll octahedral nanocage with a special pair on each edge closely matched the design model. The results suggest that the de novo design of artificial photosynthetic systems is within reach of current computational methods.
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Affiliation(s)
- Nathan M Ennist
- Institute for Protein Design, University of Washington, Seattle, WA, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
| | - Shunzhi Wang
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Madison A Kennedy
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Mariano Curti
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), Barcelona Institute of Science and Technology (BIST), Tarragona, Spain
| | | | | | - Rachel L Redler
- Department of Cell Biology and Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
| | - Valentin Maffeis
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), Barcelona Institute of Science and Technology (BIST), Tarragona, Spain
| | - Saeed Shareef
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), Barcelona Institute of Science and Technology (BIST), Tarragona, Spain
- Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona, Spain
| | - Anthony V Sica
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Ash Sueh Hua
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Arundhati P Deshmukh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Adam P Moyer
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Derrick R Hicks
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Avi Z Swartz
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Ralph A Cacho
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Nathan Novy
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Asim K Bera
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Alex Kang
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Banumathi Sankaran
- Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Amala Phadkule
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Mike Reppert
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Damian Ekiert
- Department of Cell Biology and Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Gira Bhabha
- Department of Cell Biology and Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
| | - Lance Stewart
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Justin R Caram
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Elisabet Romero
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), Barcelona Institute of Science and Technology (BIST), Tarragona, Spain
| | - C Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - David Baker
- Institute for Protein Design, University of Washington, Seattle, WA, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA.
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4
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Huang X, Vasilev C, Swainsbury D, Hunter C. Excitation energy transfer in proteoliposomes reconstituted with LH2 and RC-LH1 complexes from Rhodobacter sphaeroides. Biosci Rep 2024; 44:BSR20231302. [PMID: 38227291 PMCID: PMC10876425 DOI: 10.1042/bsr20231302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/30/2023] [Accepted: 01/16/2024] [Indexed: 01/17/2024] Open
Abstract
Light-harvesting 2 (LH2) and reaction-centre light-harvesting 1 (RC-LH1) complexes purified from the photosynthetic bacterium Rhodobacter (Rba.) sphaeroides were reconstituted into proteoliposomes either separately, or together at three different LH2:RC-LH1 ratios, for excitation energy transfer studies. Atomic force microscopy (AFM) was used to investigate the distribution and association of the complexes within the proteoliposome membranes. Absorption and fluorescence emission spectra were similar for LH2 complexes in detergent and liposomes, indicating that reconstitution retains the structural and optical properties of the LH2 complexes. Analysis of fluorescence emission shows that when LH2 forms an extensive series of contacts with other such complexes, fluorescence is quenched by 52.6 ± 1.4%. In mixed proteoliposomes, specific excitation of carotenoids in LH2 donor complexes resulted in emission of fluorescence from acceptor RC-LH1 complexes engineered to assemble with no carotenoids. Extents of energy transfer were measured by fluorescence lifetime microscopy; the 0.72 ± 0.08 ns lifetime in LH2-only membranes decreases to 0.43 ± 0.04 ns with a ratio of 2:1 LH2 to RC-LH1, and to 0.35 ± 0.05 ns for a 1:1 ratio, corresponding to energy transfer efficiencies of 40 ± 14% and 51 ± 18%, respectively. No further improvement is seen with a 0.5:1 LH2 to RC-LH1 ratio. Thus, LH2 and RC-LH1 complexes perform their light harvesting and energy transfer roles when reconstituted into proteoliposomes, providing a way to integrate native, non-native, engineered and de novo designed light-harvesting complexes into functional photosynthetic systems.
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Affiliation(s)
- Xia Huang
- Department of Biological Sciences, Xi’an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123, China
- Jinan Guoke Medical Technology Development Co., Ltd, Jinan, Shandong 250101, China
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - Cvetelin Vasilev
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - David J.K. Swainsbury
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
| | - C. Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
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5
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Qi CH, Wang GL, Wang FF, Wang J, Wang XP, Zou MJ, Ma F, Madigan MT, Kimura Y, Wang-Otomo ZY, Yu LJ. Structural insights into the unusual core photocomplex from a triply extremophilic purple bacterium, Halorhodospira halochloris. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2024. [PMID: 38411333 DOI: 10.1111/jipb.13628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/17/2024] [Accepted: 02/03/2024] [Indexed: 02/28/2024]
Abstract
Halorhodospira (Hlr.) halochloris is a triply extremophilic phototrophic purple sulfur bacterium, as it is thermophilic, alkaliphilic, and extremely halophilic. The light-harvesting-reaction center (LH1-RC) core complex of this bacterium displays an LH1-Qy transition at 1,016 nm, which is the lowest-energy wavelength absorption among all known phototrophs. Here we report the cryo-EM structure of the LH1-RC at 2.42 Å resolution. The LH1 complex forms a tricyclic ring structure composed of 16 αβγ-polypeptides and one αβ-heterodimer around the RC. From the cryo-EM density map, two previously unrecognized integral membrane proteins, referred to as protein G and protein Q, were identified. Both of these proteins are single transmembrane-spanning helices located between the LH1 ring and the RC L-subunit and are absent from the LH1-RC complexes of all other purple bacteria of which the structures have been determined so far. Besides bacteriochlorophyll b molecules (B1020) located on the periplasmic side of the Hlr. halochloris membrane, there are also two arrays of bacteriochlorophyll b molecules (B800 and B820) located on the cytoplasmic side. Only a single copy of a carotenoid (lycopene) was resolved in the Hlr. halochloris LH1-α3β3 and this was positioned within the complex. The potential quinone channel should be the space between the LH1-α3β3 that accommodates the single lycopene but does not contain a γ-polypeptide, B800 and B820. Our results provide a structural explanation for the unusual Qy red shift and carotenoid absorption in the Hlr. halochloris spectrum and reveal new insights into photosynthetic mechanisms employed by a species that thrives under the harshest conditions of any phototrophic microorganism known.
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Affiliation(s)
- Chen-Hui Qi
- Key Laboratory of Photobiology, Photosynthesis Research Center, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guang-Lei Wang
- Key Laboratory of Photobiology, Photosynthesis Research Center, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fang-Fang Wang
- Zhangjiang Lab, National Facility for Protein Science in Shanghai, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China
| | - Jie Wang
- Key Laboratory of Photobiology, Photosynthesis Research Center, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiang-Ping Wang
- Key Laboratory of Photobiology, Photosynthesis Research Center, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mei-Juan Zou
- Key Laboratory of Photobiology, Photosynthesis Research Center, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Fei Ma
- Key Laboratory of Photobiology, Photosynthesis Research Center, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Michael T Madigan
- Department of Microbiology, School of Biological Sciences, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Yukihiro Kimura
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Nada, Kobe, 657-8501, Japan
| | | | - Long-Jiang Yu
- Key Laboratory of Photobiology, Photosynthesis Research Center, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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6
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Liu LN, Bracun L, Li M. Structural diversity and modularity of photosynthetic RC-LH1 complexes. Trends Microbiol 2024; 32:38-52. [PMID: 37380557 DOI: 10.1016/j.tim.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/03/2023] [Accepted: 06/05/2023] [Indexed: 06/30/2023]
Abstract
Bacterial photosynthesis is essential for sustaining life on Earth as it aids in carbon assimilation, atmospheric composition, and ecosystem maintenance. Many bacteria utilize anoxygenic photosynthesis to convert sunlight into chemical energy while producing organic matter. The core machinery of anoxygenic photosynthesis performed by purple photosynthetic bacteria and Chloroflexales is the reaction center-light-harvesting 1 (RC-LH1) pigment-protein supercomplex. In this review, we discuss recent structural studies of RC-LH1 core complexes based on the advancement in structural biology techniques. These studies have provided fundamental insights into the assembly mechanisms, structural variations, and modularity of RC-LH1 complexes across different bacterial species, highlighting their functional adaptability. Understanding the natural architectures of RC-LH1 complexes will facilitate the design and engineering of artificial photosynthetic systems, which can enhance photosynthetic efficiency and potentially find applications in sustainable energy production and carbon capture.
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Affiliation(s)
- Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK; College of Marine Life Sciences and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266003, China.
| | - Laura Bracun
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Mei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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7
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Timpmann K, Rätsep M, Freiberg A. Dominant role of excitons in photosynthetic color-tuning and light-harvesting. Front Chem 2023; 11:1231431. [PMID: 37908232 PMCID: PMC10613661 DOI: 10.3389/fchem.2023.1231431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 10/03/2023] [Indexed: 11/02/2023] Open
Abstract
Photosynthesis is a vital process that converts sunlight into energy for the Earth's ecosystems. Color adaptation is crucial for different photosynthetic organisms to thrive in their ecological niches. Although the presence of collective excitons in light-harvesting complexes is well known, the role of delocalized excited states in color tuning and excitation energy transfer remains unclear. This study evaluates the characteristics of photosynthetic excitons in sulfur and non-sulfur purple bacteria using advanced optical spectroscopic techniques at reduced temperatures. The exciton effects in these bacteriochlorophyll a-containing species are generally much stronger than in plant systems that rely on chlorophylls. Their exciton bandwidth varies based on multiple factors such as chromoprotein structure, surroundings of the pigments, carotenoid content, hydrogen bonding, and metal ion inclusion. The study nevertheless establishes a linear relationship between the exciton bandwidth and Qy singlet exciton absorption peak, which in case of LH1 core complexes from different species covers almost 130 nm. These findings provide important insights into bacterial color tuning and light-harvesting, which can inspire sustainable energy strategies and devices.
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Affiliation(s)
- Kõu Timpmann
- Institute of Physics, University of Tartu, Tartu, Estonia
| | - Margus Rätsep
- Institute of Physics, University of Tartu, Tartu, Estonia
| | - Arvi Freiberg
- Institute of Physics, University of Tartu, Tartu, Estonia
- Estonian Academy of Sciences, Tallinn, Estonia
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8
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Xin J, Shi Y, Zhang X, Yuan X, Xin Y, He H, Shen J, Blankenship RE, Xu X. Carotenoid assembly regulates quinone diffusion and the Roseiflexus castenholzii reaction center-light harvesting complex architecture. eLife 2023; 12:e88951. [PMID: 37737710 PMCID: PMC10516601 DOI: 10.7554/elife.88951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/16/2023] [Indexed: 09/23/2023] Open
Abstract
Carotenoid (Car) pigments perform central roles in photosynthesis-related light harvesting (LH), photoprotection, and assembly of functional pigment-protein complexes. However, the relationships between Car depletion in the LH, assembly of the prokaryotic reaction center (RC)-LH complex, and quinone exchange are not fully understood. Here, we analyzed native RC-LH (nRC-LH) and Car-depleted RC-LH (dRC-LH) complexes in Roseiflexus castenholzii, a chlorosome-less filamentous anoxygenic phototroph that forms the deepest branch of photosynthetic bacteria. Newly identified exterior Cars functioned with the bacteriochlorophyll B800 to block the proposed quinone channel between LHαβ subunits in the nRC-LH, forming a sealed LH ring that was disrupted by transmembrane helices from cytochrome c and subunit X to allow quinone shuttling. dRC-LH lacked subunit X, leading to an exposed LH ring with a larger opening, which together accelerated the quinone exchange rate. We also assigned amino acid sequences of subunit X and two hypothetical proteins Y and Z that functioned in forming the quinone channel and stabilizing the RC-LH interactions. This study reveals the structural basis by which Cars assembly regulates the architecture and quinone exchange of bacterial RC-LH complexes. These findings mark an important step forward in understanding the evolution and diversity of prokaryotic photosynthetic apparatus.
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Affiliation(s)
- Jiyu Xin
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences and The Affiliated Hospital of Hangzhou Normal UniversityHangzhouChina
| | - Yang Shi
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence & Department of Neurobiology and Department of Pathology of the First Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang UniversityHangzhouChina
| | - Xin Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences and The Affiliated Hospital of Hangzhou Normal UniversityHangzhouChina
- Photosynthesis Research Center, College of Life and Environmental Sciences, Hangzhou Normal UniversityHangzhouChina
| | - Xinyi Yuan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences and The Affiliated Hospital of Hangzhou Normal UniversityHangzhouChina
- Photosynthesis Research Center, College of Life and Environmental Sciences, Hangzhou Normal UniversityHangzhouChina
| | - Yueyong Xin
- Photosynthesis Research Center, College of Life and Environmental Sciences, Hangzhou Normal UniversityHangzhouChina
| | - Huimin He
- Photosynthesis Research Center, College of Life and Environmental Sciences, Hangzhou Normal UniversityHangzhouChina
| | - Jiejie Shen
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences and The Affiliated Hospital of Hangzhou Normal UniversityHangzhouChina
| | - Robert E Blankenship
- Departments of Biology and Chemistry, Washington University in St. LouisSt. LouisUnited States
| | - Xiaoling Xu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences and The Affiliated Hospital of Hangzhou Normal UniversityHangzhouChina
- Photosynthesis Research Center, College of Life and Environmental Sciences, Hangzhou Normal UniversityHangzhouChina
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9
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Qi CH, Wang GL, Wang FF, Xin Y, Zou MJ, Madigan MT, Wang-Otomo ZY, Ma F, Yu LJ. New insights on the photocomplex of Roseiflexus castenholzii revealed from comparisons of native and carotenoid-depleted complexes. J Biol Chem 2023; 299:105057. [PMID: 37468106 PMCID: PMC10432797 DOI: 10.1016/j.jbc.2023.105057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/08/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023] Open
Abstract
In wild-type phototrophic organisms, carotenoids (Crts) are primarily packed into specific pigment-protein complexes along with (Bacterio)chlorophylls and play important roles in the photosynthesis. Diphenylamine (DPA) inhibits carotenogenesis but not phototrophic growth of anoxygenic phototrophs and eliminates virtually all Crts from photocomplexes. To investigate the effect of Crts on assembly of the reaction center-light-harvesting (RC-LH) complex from the filamentous anoxygenic phototroph Roseiflexus (Rfl.) castenholzii, we generated carotenoidless (Crt-less) RC-LH complexes by growing cells in the presence of DPA. Here, we present cryo-EM structures of the Rfl. castenholzii native and Crt-less RC-LH complexes with resolutions of 2.86 Å and 2.85 Å, respectively. From the high-quality map obtained, several important but previously unresolved details in the Rfl. castenholzii RC-LH structure were determined unambiguously including the assignment and likely function of three small polypeptides, and the content and spatial arrangement of Crts with bacteriochlorophyll molecules. The overall structures of Crt-containing and Crt-less complexes are similar. However, structural comparisons showed that only five Crts remain in complexes from DPA-treated cells and that the subunit X (TMx) flanked on the N-terminal helix of the Cyt-subunit is missing. Based on these results, the function of Crts in the assembly of the Rfl. castenholzii RC-LH complex and the molecular mechanism of quinone exchange is discussed. These structural details provide a fresh look at the photosynthetic apparatus of an evolutionary ancient phototroph as well as new insights into the importance of Crts for proper assembly and functioning of the RC-LH complex.
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Affiliation(s)
- Chen-Hui Qi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Guang-Lei Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Fang-Fang Wang
- National Facility for Protein Science in Shanghai, Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Science, Shanghai, China
| | - Yueyong Xin
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Mei-Juan Zou
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Michael T Madigan
- Department of Microbiology, School of Biological Sciences, Southern Illinois University, Carbondale, Illinois, USA
| | | | - Fei Ma
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
| | - Long-Jiang Yu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
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10
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Gardiner AT, Mujakić I, Bína D, Gardian Z, Kopejtka K, Nupur, Qian P, Koblížek M. Characterisation of the photosynthetic complexes from the marine gammaproteobacterium Congregibacter litoralis KT71. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148946. [PMID: 36455648 DOI: 10.1016/j.bbabio.2022.148946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 11/02/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022]
Abstract
Possibly the most abundant group of anoxygenic phototrophs are marine photoheterotrophic Gammaproteobacteria belonging to the NOR5/OM60 clade. As little is known about their photosynthetic apparatus, the photosynthetic complexes from the marine phototrophic bacterium Congregibacter litoralis KT71 were purified and spectroscopically characterised. The intra-cytoplasmic membranes contain a smaller amount of photosynthetic complexes when compared with anaerobic purple bacteria. Moreover, the intra-cytoplasmic membranes contain only a minimum amount of peripheral LH2 complexes. The complexes are populated by bacteriochlorophyll a, spirilloxanthin and two novel ketocarotenoids, with biophysical and biochemical properties similar to previously characterised complexes from purple bacteria. The organization of the RC-LH1 complex has been further characterised using cryo-electron microscopy. The overall organisation is similar to the complex from the gammaproteobacterium Thermochromatium tepidum, with the type-II reaction centre surrounded by a slightly elliptical LH1 antenna ring composed of 16 αβ-subunits with no discernible gap or pore. The RC-LH1 and LH2 apoproteins are phylogenetically related to other halophilic species but LH2 also to some alphaproteobacterial species. It seems that the reduction of light-harvesting apparatus and acquisition of novel ketocarotenoids in Congregibacter litoralis KT71 represent specific adaptations for operating the anoxygenic photosynthesis under aerobic conditions at sea.
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Affiliation(s)
- Alastair T Gardiner
- Institute of Microbiology of the Czech Academy of Sciences, 379 81 Třeboň, Czech Republic
| | - Izabela Mujakić
- Institute of Microbiology of the Czech Academy of Sciences, 379 81 Třeboň, Czech Republic; Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic
| | - David Bína
- Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic; Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Zdenko Gardian
- Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic; Biology Centre, Czech Academy of Sciences, Institute of Parasitology, Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Karel Kopejtka
- Institute of Microbiology of the Czech Academy of Sciences, 379 81 Třeboň, Czech Republic
| | - Nupur
- Institute of Microbiology of the Czech Academy of Sciences, 379 81 Třeboň, Czech Republic
| | - Pu Qian
- Materials and Structure Analysis, Thermofisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
| | - Michal Koblížek
- Institute of Microbiology of the Czech Academy of Sciences, 379 81 Třeboň, Czech Republic; Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic.
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11
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Bracun L, Yamagata A, Christianson BM, Shirouzu M, Liu LN. Cryo-EM structure of a monomeric RC-LH1-PufX supercomplex with high-carotenoid content from Rhodobacter capsulatus. Structure 2023; 31:318-328.e3. [PMID: 36738736 DOI: 10.1016/j.str.2023.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/30/2022] [Accepted: 01/11/2023] [Indexed: 02/05/2023]
Abstract
In purple photosynthetic bacteria, the photochemical reaction center (RC) and light-harvesting complex 1 (LH1) assemble to form monomeric or dimeric RC-LH1 membrane complexes, essential for bacterial photosynthesis. Here, we report a 2.59-Å resolution cryoelectron microscopy (cryo-EM) structure of the RC-LH1 supercomplex from Rhodobacter capsulatus. We show that Rba. capsulatus RC-LH1 complexes are exclusively monomers in which the RC is surrounded by a 15-subunit LH1 ring. Incorporation of a transmembrane polypeptide PufX leads to a large opening within the LH1 ring. Each LH1 subunit associates two carotenoids and two bacteriochlorophylls, which is similar to Rba. sphaeroides RC-LH1 but more than one carotenoid per LH1 in Rba. veldkampii RC-LH1 monomer. Collectively, the unique Rba. capsulatus RC-LH1-PufX represents an intermediate structure between Rba. sphaeroides and Rba. veldkampii RC-LH1-PufX. Comparison of PufX from the three Rhodobacter species indicates the important residues involved in dimerization of RC-LH1.
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Affiliation(s)
- Laura Bracun
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK; Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Atsushi Yamagata
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Bern M Christianson
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Mikako Shirouzu
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK; College of Marine Life Sciences and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266003, China.
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12
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Tani K, Kanno R, Ji XC, Satoh I, Kobayashi Y, Hall M, Yu LJ, Kimura Y, Mizoguchi A, Humbel BM, Madigan MT, Wang-Otomo ZY. Rhodobacter capsulatus forms a compact crescent-shaped LH1-RC photocomplex. Nat Commun 2023; 14:846. [PMID: 36792596 PMCID: PMC9932092 DOI: 10.1038/s41467-023-36460-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 02/01/2023] [Indexed: 02/17/2023] Open
Abstract
Rhodobacter (Rba.) capsulatus has been a favored model for studies of all aspects of bacterial photosynthesis. This purple phototroph contains PufX, a polypeptide crucial for dimerization of the light-harvesting 1-reaction center (LH1-RC) complex, but lacks protein-U, a U-shaped polypeptide in the LH1-RC of its close relative Rba. sphaeroides. Here we present a cryo-EM structure of the Rba. capsulatus LH1-RC purified by DEAE chromatography. The crescent-shaped LH1-RC exhibits a compact structure containing only 10 LH1 αβ-subunits. Four αβ-subunits corresponding to those adjacent to protein-U in Rba. sphaeroides were absent. PufX in Rba. capsulatus exhibits a unique conformation in its N-terminus that self-associates with amino acids in its own transmembrane domain and interacts with nearby polypeptides, preventing it from interacting with proteins in other complexes and forming dimeric structures. These features are discussed in relation to the minimal requirements for the formation of LH1-RC monomers and dimers, the spectroscopic behavior of both the LH1 and RC, and the bioenergetics of energy transfer from LH1 to the RC.
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Affiliation(s)
- Kazutoshi Tani
- Graduate School of Medicine, Mie University, Tsu, Japan.
| | - Ryo Kanno
- Scientific Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-Son, Kunigami-Gun, Okinawa, Japan.,Quantum wave microscopy unit, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-Son, Kunigami-Gun, Okinawa, Japan
| | | | | | | | - Malgorzata Hall
- Scientific Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-Son, Kunigami-Gun, Okinawa, Japan
| | - Long-Jiang Yu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Yukihiro Kimura
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe, Japan
| | | | - Bruno M Humbel
- Scientific Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-Son, Kunigami-Gun, Okinawa, Japan.,Department of Cell Biology and Neuroscience, Juntendo University, Graduate School of Medicine, Tokyo, Japan
| | - Michael T Madigan
- School of Biological Sciences, Department of Microbiology, Southern Illinois University, Carbondale, IL, USA
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13
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Kimura Y, Tani K, Madigan MT, Wang-Otomo ZY. Advances in the Spectroscopic and Structural Characterization of Core Light-Harvesting Complexes from Purple Phototrophic Bacteria. J Phys Chem B 2023; 127:6-17. [PMID: 36594654 DOI: 10.1021/acs.jpcb.2c06638] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Purple phototrophic bacteria are ancient anoxygenic phototrophs and attractive research tools because they capture light energy in the near-infrared (NIR) region of the spectrum and transform it into chemical energy by way of uphill energy transfers. The heart of this reaction occurs in light-harvesting 1-reaction center (LH1-RC) complexes, which are the simplest model systems for understanding basic photosynthetic reactions within type-II (quinone-utilizing) reaction centers. In this Perspective, we highlight structure-function relationships concerning unresolved fundamental processes in purple bacterial photosynthesis, including the diversified light-harvesting capacity of LH1-associated BChl molecules, energies necessary for photoelectric conversion in the RC special pairs, and quinone transport mechanisms. Based on recent progress in the spectroscopic and structural analysis of LH1-RC complexes from a variety of purple phototrophs, we discuss several key factors for understanding how purple bacteria resource light energy in the inherently energy-poor NIR region of the electromagnetic spectrum.
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Affiliation(s)
- Yukihiro Kimura
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
| | - Kazutoshi Tani
- Graduate School of Medicine, Mie University, Tsu 514-8507, Japan
| | - Michael T Madigan
- Department of Microbiology, School of Biological Sciences, Southern Illinois University, Carbondale, Illinois 62901, United States
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14
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Liu XL, Hu YY, Li K, Chen MQ, Wang P. Reconstituted LH2 in multilayer membranes induced by poly-L-lysine: structure of supramolecular and electronic states. ARAB J CHEM 2023. [DOI: 10.1016/j.arabjc.2023.104600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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15
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The role of the γ subunit in the photosystem of the lowest-energy phototrophs. Biochem J 2022; 479:2449-2463. [PMID: 36534468 PMCID: PMC9788563 DOI: 10.1042/bcj20220508] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022]
Abstract
Purple phototrophic bacteria use a 'photosystem' consisting of light harvesting complex 1 (LH1) surrounding the reaction centre (RC) that absorbs far-red-near-infrared light and converts it to chemical energy. Blastochloris species, which harvest light >1000 nm, use bacteriochlorophyll b rather than the more common bacteriochlorophyll a as their major photopigment, and assemble LH1 with an additional polypeptide subunit, LH1γ, encoded by multiple genes. To assign a role to γ, we deleted the four encoding genes in the model Blastochloris viridis. Interestingly, growth under halogen bulbs routinely used for cultivation yielded cells displaying an absorption maximum of 825 nm, similar to that of the RC only, but growth under white light yielded cells with an absorption maximum at 972 nm. HPLC analysis of pigment composition and sucrose gradient fractionation demonstrate that the white light-grown mutant assembles RC-LH1, albeit with an absorption maximum blue-shifted by 46 nm. Wavelengths between 900-1000 nm transmit poorly through the atmosphere due to absorption by water, so our results provide an evolutionary rationale for incorporation of γ; this polypeptide red-shifts absorption of RC-LH1 to a spectral range in which photons are of lower energy but are more abundant. Finally, we transformed the mutant with plasmids encoding natural LH1γ variants and demonstrate that the polypeptide found in the wild type complex red-shifts absorption back to 1018 nm, but incorporation of a distantly related variant results in only a moderate shift. This result suggests that tuning the absorption of RC-LH1 is possible and may permit photosynthesis past its current low-energy limit.
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16
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Elvers I, Nguyen-Phan TC, Gardiner AT, Hunter CN, Cogdell RJ, Köhler J. Phasor Analysis Reveals Multicomponent Fluorescence Kinetics in the LH2 Complex from Marichromatium purpuratum. J Phys Chem B 2022; 126:10335-10346. [PMID: 36449272 DOI: 10.1021/acs.jpcb.2c04983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
We investigated the fluorescence kinetics of LH2 complexes from Marichromatium purpuratum, the cryo-EM structure of which has been recently elucidated with 2.4 Å resolution. The experiments have been carried out as a function of the excitation density by varying both the excitation fluence and the repetition rate of the laser excitation. Instead of the usual multiexponential fitting procedure, we applied the less common phasor formalism for evaluating the transients because this allows for a model-free analysis of the data without a priori knowledge about the number of processes that contribute to a particular decay. For the various excitation conditions, this analysis reproduces consistently three lifetime components with decay times below 100 ps, 500 ps, and 730 ps, which were associated with the quenched state, singlet-triplet annihilation, and fluorescence decay, respectively. Moreover, it reveals that the number of decay components that contribute to the transients depends on whether the excitation wavelength is in resonance with the B800 BChl a molecules or with the carotenoids. Based on the mutual arrangement of the chromophores in their binding pockets, this leads us to conclude that the energy transfer pathways within the LH2 complex of this species differ significantly from each other for exciting either the B800 BChl molecules or the carotenoids. Finally, we speculate whether the illumination with strong laser light converts the LH2 complexes studied here into a quenched conformation that might be related to the development of the non-photochemical quenching mechanism that occurs in higher plants.
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Affiliation(s)
- Inga Elvers
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstr. 30, D-95440 Bayreuth, Germany
| | - Tu C Nguyen-Phan
- School of Infection and Immunity, Glasgow University, Glasgow G12 8TA, U.K
| | - Alastair T Gardiner
- Laboratory of Anoxygenic Phototrophs, Institute of Microbiology, Czech Academy of Sciences, 379 81 Třeboň, Czech Republic
| | - C Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - Richard J Cogdell
- School of Molecular Biosciences, Glasgow University, Glasgow G12 8QQ, U.K
| | - Jürgen Köhler
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstr. 30, D-95440 Bayreuth, Germany.,Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, Universitätsstr. 30, D-95440 Bayreuth, Germany.,Bavarian Polymer Institute, University of Bayreuth, Universitätsstr. 30, D-95440 Bayreuth, Germany
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17
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Tani K, Kanno R, Kurosawa K, Takaichi S, Nagashima KVP, Hall M, Yu LJ, Kimura Y, Madigan MT, Mizoguchi A, Humbel BM, Wang-Otomo ZY. An LH1–RC photocomplex from an extremophilic phototroph provides insight into origins of two photosynthesis proteins. Commun Biol 2022; 5:1197. [DOI: 10.1038/s42003-022-04174-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/26/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractRhodopila globiformis is the most acidophilic of anaerobic purple phototrophs, growing optimally in culture at pH 5. Here we present a cryo-EM structure of the light-harvesting 1–reaction center (LH1–RC) complex from Rhodopila globiformis at 2.24 Å resolution. All purple bacterial cytochrome (Cyt, encoded by the gene pufC) subunit-associated RCs with known structures have their N-termini truncated. By contrast, the Rhodopila globiformis RC contains a full-length tetra-heme Cyt with its N-terminus embedded in the membrane forming an α-helix as the membrane anchor. Comparison of the N-terminal regions of the Cyt with PufX polypeptides widely distributed in Rhodobacter species reveals significant structural similarities, supporting a longstanding hypothesis that PufX is phylogenetically related to the N-terminus of the RC-bound Cyt subunit and that a common ancestor of phototrophic Proteobacteria contained a full-length tetra-heme Cyt subunit that evolved independently through partial deletions of its pufC gene. Eleven copies of a novel γ-like polypeptide were also identified in the bacteriochlorophyll a-containing Rhodopila globiformis LH1 complex; γ-polypeptides have previously been found only in the LH1 of bacteriochlorophyll b-containing species. These features are discussed in relation to their predicted functions of stabilizing the LH1 structure and regulating quinone transport under the warm acidic conditions.
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18
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Du J, Xin J, Liu M, Zhang X, He H, Wu J, Xu X. Preparation of Photo-Bioelectrochemical Cells With the RC-LH Complex From Roseiflexus castenholzii. Front Microbiol 2022; 13:928046. [PMID: 35783423 PMCID: PMC9243436 DOI: 10.3389/fmicb.2022.928046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/30/2022] [Indexed: 11/13/2022] Open
Abstract
Roseiflexus castenholzii is an ancient green non-sulfur bacteria that absorbs the solar energy through bacteriochlorophylls (BChls) bound in the only light harvesting (LH) complex, and transfers to the reaction center (RC), wherein primary charge separation occurs and transforms the energy into electrochemical potentials. In contrast to purple bacteria, R. castenholzii RC-LH (rcRC-LH) does not contain an H subunit. Instead, a tightly bound tetraheme cytochrome c subunit is exposed on the P-side of the RC, which contains three BChls, three bacteriopheophytins (BPheos), two menaquinones, and one iron for electron transfer. These novel structural features of the rcRC-LH are advantageous for enhancing the electron transfer efficiency and subsequent photo-oxidation of the c-type hemes. However, the photochemical properties of rcRC-LH and its applications in developing the photo-bioelectrochemical cells (PBECs) have not been characterized. Here, we prepared a PBEC using overlapped fluorine-doped tin oxide (FTO) glass and Pt-coated glass as electrodes, and rcRC-LH mixed with varying mediators as the electrolyte. Absence of the H subunit allows rcRC-LH to be selectively adhered onto the hydrophilic surface of the front electrode with its Q-side. Upon illumination, the photogenerated electrons directly enter the front electrode and transfer to the counter electrode, wherein the accepted electrons pass through the exposed c-type hemes to reduce the excited P+, generating a steady-state current of up to 320 nA/cm2 when using 1-Methoxy-5-methylphenazinium methyl sulfate (PMS) as mediator. This study demonstrated the novel photoelectric properties of rcRC-LH and its advantages in preparing effective PBECs, showcasing a potential of this complex in developing new type PBECs.
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Affiliation(s)
- Jinsong Du
- Photosynthesis Research Center, Hangzhou Normal University, Hangzhou, China
| | - Jiyu Xin
- Photosynthesis Research Center, Hangzhou Normal University, Hangzhou, China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China
| | - Menghua Liu
- Photosynthesis Research Center, Hangzhou Normal University, Hangzhou, China
| | - Xin Zhang
- Photosynthesis Research Center, Hangzhou Normal University, Hangzhou, China
| | - Huimin He
- Photosynthesis Research Center, Hangzhou Normal University, Hangzhou, China
| | - Jingyi Wu
- Photosynthesis Research Center, Hangzhou Normal University, Hangzhou, China
| | - Xiaoling Xu
- Photosynthesis Research Center, Hangzhou Normal University, Hangzhou, China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China
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19
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Båth P, Banacore A, Börjesson P, Bosman R, Wickstrand C, Safari C, Dods R, Ghosh S, Dahl P, Ortolani G, Björg Ulfarsdottir T, Hammarin G, García Bonete MJ, Vallejos A, Ostojić L, Edlund P, Linse JB, Andersson R, Nango E, Owada S, Tanaka R, Tono K, Joti Y, Nureki O, Luo F, James D, Nass K, Johnson PJM, Knopp G, Ozerov D, Cirelli C, Milne C, Iwata S, Brändén G, Neutze R. Lipidic cubic phase serial femtosecond crystallography structure of a photosynthetic reaction centre. Acta Crystallogr D Struct Biol 2022; 78:698-708. [PMID: 35647917 PMCID: PMC9159286 DOI: 10.1107/s2059798322004144] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/19/2022] [Indexed: 03/28/2024] Open
Abstract
Serial crystallography is a rapidly growing method that can yield structural insights from microcrystals that were previously considered to be too small to be useful in conventional X-ray crystallography. Here, conditions for growing microcrystals of the photosynthetic reaction centre of Blastochloris viridis within a lipidic cubic phase (LCP) crystallization matrix that employ a seeding protocol utilizing detergent-grown crystals with a different crystal packing are described. LCP microcrystals diffracted to 2.25 Å resolution when exposed to XFEL radiation, which is an improvement of 0.15 Å over previous microcrystal forms. Ubiquinone was incorporated into the LCP crystallization media and the resulting electron density within the mobile QB pocket is comparable to that of other cofactors within the structure. As such, LCP microcrystallization conditions will facilitate time-resolved diffraction studies of electron-transfer reactions to the mobile quinone, potentially allowing the observation of structural changes associated with the two electron-transfer reactions leading to complete reduction of the ubiquinone ligand.
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Affiliation(s)
- Petra Båth
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Analia Banacore
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Per Börjesson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Robert Bosman
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Cecilia Wickstrand
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Cecilia Safari
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Robert Dods
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Swagatha Ghosh
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Peter Dahl
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Giorgia Ortolani
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Tinna Björg Ulfarsdottir
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Greger Hammarin
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - María-José García Bonete
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Adams Vallejos
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Lucija Ostojić
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Petra Edlund
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Johanna-Barbara Linse
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Rebecka Andersson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Eriko Nango
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Shigeki Owada
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Rie Tanaka
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Kensuke Tono
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Yasumasa Joti
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Fangjia Luo
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Daniel James
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Karol Nass
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Philip J. M. Johnson
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Gregor Knopp
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Dmitry Ozerov
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Claudio Cirelli
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Christopher Milne
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - So Iwata
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Gisela Brändén
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
| | - Richard Neutze
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundbergslaboratoriet Box 462, 405 30 Göteborg, Sweden
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20
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Zhang Y, Qi CH, Yamano N, Wang P, Yu LJ, Wang-Otomo ZY, Zhang JP. Carotenoid Single-Molecular Singlet Fission and the Photoprotection of a Bacteriochlorophyll b-Type Core Light-Harvesting Antenna. J Phys Chem Lett 2022; 13:3534-3541. [PMID: 35420425 DOI: 10.1021/acs.jpclett.2c00519] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Carotenoid (Car) in photosynthesis plays the major roles of accessary light harvesting and photoprotection, and the underlying structure-function relationship attracts continuing research interests. We have attempted to explore the dynamics of Car triplet excitation (3Car*) in the bacteriochlorophyll b (BChl b)-type light harvesting reaction center complex (LH1-RC) of photosynthetic bacterium Halorhodospira halochloris. We show that the LH1 antenna binds a single Car that was identified as a lycopene derivative. Although the Car is hardly visible in the LH1-RC stationary absorption, it shows up conspicuously in the triplet excitation profile with distinct vibronic features. This and the ultrafast formation of 3Car* on direct photoexcitation of Car unequivocally manifest the unimolecular singlet fission reaction of the Car. Moreover, the Car with even one molecule per complex is found to be rather effective in quenching 3BChl b*. The implications of different 3Car* formation mechanisms are discussed, and the self-photoprotection role of BChl b are proposed for this extremophilic species.
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Affiliation(s)
- Yan Zhang
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing 1000872, P. R. China
| | - Chen-Hui Qi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, P. R. China
| | - Nami Yamano
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing 1000872, P. R. China
| | - Peng Wang
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing 1000872, P. R. China
| | - Long-Jiang Yu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, P. R. China
| | | | - Jian-Ping Zhang
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing 1000872, P. R. China
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21
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Structural basis for the assembly and quinone transport mechanisms of the dimeric photosynthetic RC-LH1 supercomplex. Nat Commun 2022; 13:1977. [PMID: 35418573 PMCID: PMC9007983 DOI: 10.1038/s41467-022-29563-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 03/22/2022] [Indexed: 12/15/2022] Open
Abstract
The reaction center (RC) and light-harvesting complex 1 (LH1) form a RC-LH1 core supercomplex that is vital for the primary reactions of photosynthesis in purple phototrophic bacteria. Some species possess the dimeric RC-LH1 complex with a transmembrane polypeptide PufX, representing the largest photosynthetic complex in anoxygenic phototrophs. However, the details of the architecture and assembly mechanism of the RC-LH1 dimer are unclear. Here we report seven cryo-electron microscopy (cryo-EM) structures of RC-LH1 supercomplexes from Rhodobacter sphaeroides. Our structures reveal that two PufX polypeptides are positioned in the center of the S-shaped RC-LH1 dimer, interlocking association between the components and mediating RC-LH1 dimerization. Moreover, we identify another transmembrane peptide, designated PufY, which is located between the RC and LH1 subunits near the LH1 opening. PufY binds a quinone molecule and prevents LH1 subunits from completely encircling the RC, creating a channel for quinone/quinol exchange. Genetic mutagenesis, cryo-EM structures, and computational simulations provide a mechanistic understanding of the assembly and electron transport pathways of the RC-LH1 dimer and elucidate the roles of individual components in ensuring the structural and functional integrity of the photosynthetic supercomplex.
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22
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Tani K, Kanno R, Kikuchi R, Kawamura S, Nagashima KVP, Hall M, Takahashi A, Yu LJ, Kimura Y, Madigan MT, Mizoguchi A, Humbel BM, Wang-Otomo ZY. Asymmetric structure of the native Rhodobacter sphaeroides dimeric LH1-RC complex. Nat Commun 2022; 13:1904. [PMID: 35393413 PMCID: PMC8991256 DOI: 10.1038/s41467-022-29453-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 03/08/2022] [Indexed: 11/18/2022] Open
Abstract
Rhodobacter sphaeroides is a model organism in bacterial photosynthesis, and its light-harvesting-reaction center (LH1-RC) complex contains both dimeric and monomeric forms. Here we present cryo-EM structures of the native LH1-RC dimer and an LH1-RC monomer lacking protein-U (ΔU). The native dimer reveals several asymmetric features including the arrangement of its two monomeric components, the structural integrity of protein-U, the overall organization of LH1, and rigidities of the proteins and pigments. PufX plays a critical role in connecting the two monomers in a dimer, with one PufX interacting at its N-terminus with another PufX and an LH1 β-polypeptide in the other monomer. One protein-U was only partially resolved in the dimeric structure, signaling different degrees of disorder in the two monomers. The ΔU LH1-RC monomer was half-moon-shaped and contained 11 α- and 10 β-polypeptides, indicating a critical role for protein-U in controlling the number of αβ-subunits required for dimer assembly and stabilization. These features are discussed in relation to membrane topology and an assembly model proposed for the native dimeric complex.
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Affiliation(s)
- Kazutoshi Tani
- Graduate School of Medicine, Mie University, Tsu, 514-8507, Japan.
| | - Ryo Kanno
- Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Riku Kikuchi
- Faculty of Science, Ibaraki University, Mito, 310-8512, Japan
| | - Saki Kawamura
- Faculty of Science, Ibaraki University, Mito, 310-8512, Japan
| | - Kenji V P Nagashima
- Research Institute for Integrated Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa, 259-1293, Japan
| | - Malgorzata Hall
- Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Ai Takahashi
- Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Long-Jiang Yu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Yukihiro Kimura
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe, 657-8501, Japan
| | - Michael T Madigan
- School of Biological Sciences, Department of Microbiology, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Akira Mizoguchi
- Graduate School of Medicine, Mie University, Tsu, 514-8507, Japan
| | - Bruno M Humbel
- Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
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23
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Qian P, Gardiner AT, Šímová I, Naydenova K, Croll TI, Jackson PJ, Nupur, Kloz M, Čubáková P, Kuzma M, Zeng Y, Castro-Hartmann P, van Knippenberg B, Goldie KN, Kaftan D, Hrouzek P, Hájek J, Agirre J, Siebert CA, Bína D, Sader K, Stahlberg H, Sobotka R, Russo CJ, Polívka T, Hunter CN, Koblížek M. 2.4-Å structure of the double-ring Gemmatimonas phototrophica photosystem. SCIENCE ADVANCES 2022; 8:eabk3139. [PMID: 35171663 PMCID: PMC8849296 DOI: 10.1126/sciadv.abk3139] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 12/22/2021] [Indexed: 07/21/2023]
Abstract
Phototrophic Gemmatimonadetes evolved the ability to use solar energy following horizontal transfer of photosynthesis-related genes from an ancient phototrophic proteobacterium. The electron cryo-microscopy structure of the Gemmatimonas phototrophica photosystem at 2.4 Å reveals a unique, double-ring complex. Two unique membrane-extrinsic polypeptides, RC-S and RC-U, hold the central type 2 reaction center (RC) within an inner 16-subunit light-harvesting 1 (LH1) ring, which is encircled by an outer 24-subunit antenna ring (LHh) that adds light-gathering capacity. Femtosecond kinetics reveal the flow of energy within the RC-dLH complex, from the outer LHh ring to LH1 and then to the RC. This structural and functional study shows that G. phototrophica has independently evolved its own compact, robust, and highly effective architecture for harvesting and trapping solar energy.
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Affiliation(s)
- Pu Qian
- Materials and Structural Analysis, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Alastair T. Gardiner
- Center Algatech, Institute of Microbiology, Czech Academy of Sciences, 37981 Třeboň, Czechia
| | - Ivana Šímová
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czechia
| | - Katerina Naydenova
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Tristan I. Croll
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Philip J. Jackson
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Nupur
- Center Algatech, Institute of Microbiology, Czech Academy of Sciences, 37981 Třeboň, Czechia
| | - Miroslav Kloz
- ELI Beamlines, Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 21 Prague, Czechia
| | - Petra Čubáková
- ELI Beamlines, Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 21 Prague, Czechia
| | - Marek Kuzma
- Lab of Molecular Structure, Institute of Microbiology, Czech Academy of Sciences, Prague, Czechia
| | - Yonghui Zeng
- Department of Plant and Environmental Sciences, University of Copenhagen, Nørregade 10, DK-1165 Copenhagen, Denmark
| | - Pablo Castro-Hartmann
- Materials and Structural Analysis, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
| | - Bart van Knippenberg
- Materials and Structural Analysis, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
| | - Kenneth N. Goldie
- BioEM lab, Biozentrum, University of Basel, Mattenstrasse 26, 4058 Basel, Switzerland
| | - David Kaftan
- Center Algatech, Institute of Microbiology, Czech Academy of Sciences, 37981 Třeboň, Czechia
| | - Pavel Hrouzek
- Center Algatech, Institute of Microbiology, Czech Academy of Sciences, 37981 Třeboň, Czechia
| | - Jan Hájek
- Center Algatech, Institute of Microbiology, Czech Academy of Sciences, 37981 Třeboň, Czechia
| | - Jon Agirre
- Department of Chemistry, University of York, York YO10 5DD, UK
| | | | - David Bína
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czechia
| | - Kasim Sader
- Materials and Structural Analysis, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
| | - Henning Stahlberg
- Laboratory of Biological Electron Microscopy, Institute of Physics, SB, EPFL, and Faculty of Biology and Medicine, Uni Lausanne, CH-1015 Lausanne, Switzerland
| | - Roman Sobotka
- Center Algatech, Institute of Microbiology, Czech Academy of Sciences, 37981 Třeboň, Czechia
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czechia
| | - Christopher J. Russo
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Tomáš Polívka
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czechia
| | - C. Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Michal Koblížek
- Center Algatech, Institute of Microbiology, Czech Academy of Sciences, 37981 Třeboň, Czechia
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24
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Vasilev C, Swainsbury DJK, Cartron ML, Martin EC, Kumar S, Hobbs JK, Johnson MP, Hitchcock A, Hunter CN. FRET measurement of cytochrome bc 1 and reaction centre complex proximity in live Rhodobacter sphaeroides cells. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148508. [PMID: 34793767 DOI: 10.1016/j.bbabio.2021.148508] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/27/2021] [Accepted: 11/09/2021] [Indexed: 11/30/2022]
Abstract
In the model purple phototrophic bacterium Rhodobacter (Rba.) sphaeroides, solar energy is converted via coupled electron and proton transfer reactions within the intracytoplasmic membranes (ICMs), infoldings of the cytoplasmic membrane that form spherical 'chromatophore' vesicles. These bacterial 'organelles' are ideal model systems for studying how the organisation of the photosynthetic complexes therein shape membrane architecture. In Rba. sphaeroides, light-harvesting 2 (LH2) complexes transfer absorbed excitation energy to dimeric reaction centre (RC)-LH1-PufX complexes. The PufX polypeptide creates a channel that allows the lipid soluble electron carrier quinol, produced by RC photochemistry, to diffuse to the cytochrome bc1 complex, where quinols are oxidised to quinones, with the liberated protons used to generate a transmembrane proton gradient and the electrons returned to the RC via cytochrome c2. Proximity between cytochrome bc1 and RC-LH1-PufX minimises quinone/quinol/cytochrome c2 diffusion distances within this protein-crowded membrane, however this distance has not yet been measured. Here, we tag the RC and cytochrome bc1 with yellow or cyan fluorescent proteins (YFP/CFP) and record the lifetimes of YFP/CFP Förster resonance energy transfer (FRET) pairs in whole cells. FRET analysis shows that that these complexes lie on average within 6 nm of each other. Complementary high-resolution atomic force microscopy (AFM) of intact, purified chromatophores verifies the close association of cytochrome bc1 complexes with RC-LH1-PufX dimers. Our results provide a structural basis for the close kinetic coupling between RC-LH1-PufX and cytochrome bc1 observed by spectroscopy, and explain how quinols/quinones and cytochrome c2 shuttle on a millisecond timescale between these complexes, sustaining efficient photosynthetic electron flow.
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Affiliation(s)
- Cvetelin Vasilev
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
| | - David J K Swainsbury
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Michael L Cartron
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Elizabeth C Martin
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Sandip Kumar
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7HR, United Kingdom; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Jamie K Hobbs
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7HR, United Kingdom
| | - Matthew P Johnson
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Andrew Hitchcock
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - C Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
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25
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Sutherland GA, Qian P, Hunter CN, Swainsbury DJ, Hitchcock A. Engineering purple bacterial carotenoid biosynthesis to study the roles of carotenoids in light-harvesting complexes. Methods Enzymol 2022; 674:137-184. [DOI: 10.1016/bs.mie.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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26
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Cryo-EM structure of the dimeric Rhodobacter sphaeroides RC-LH1 core complex at 2.9 Å: the structural basis for dimerisation. Biochem J 2021; 478:3923-3937. [PMID: 34622934 PMCID: PMC8652583 DOI: 10.1042/bcj20210696] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/07/2021] [Accepted: 10/07/2021] [Indexed: 11/23/2022]
Abstract
The dimeric reaction centre light-harvesting 1 (RC-LH1) core complex of Rhodobacter sphaeroides converts absorbed light energy to a charge separation, and then it reduces a quinone electron and proton acceptor to a quinol. The angle between the two monomers imposes a bent configuration on the dimer complex, which exerts a major influence on the curvature of the membrane vesicles, known as chromatophores, where the light-driven photosynthetic reactions take place. To investigate the dimerisation interface between two RC-LH1 monomers, we determined the cryogenic electron microscopy structure of the dimeric complex at 2.9 Å resolution. The structure shows that each monomer consists of a central RC partly enclosed by a 14-subunit LH1 ring held in an open state by PufX and protein-Y polypeptides, thus enabling quinones to enter and leave the complex. Two monomers are brought together through N-terminal interactions between PufX polypeptides on the cytoplasmic side of the complex, augmented by two novel transmembrane polypeptides, designated protein-Z, that bind to the outer faces of the two central LH1 β polypeptides. The precise fit at the dimer interface, enabled by PufX and protein-Z, by C-terminal interactions between opposing LH1 αβ subunits, and by a series of interactions with a bound sulfoquinovosyl diacylglycerol lipid, bring together each monomer creating an S-shaped array of 28 bacteriochlorophylls. The seamless join between the two sets of LH1 bacteriochlorophylls provides a path for excitation energy absorbed by one half of the complex to migrate across the dimer interface to the other half.
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