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Hahn AW, Zsombor-Pindera J, Kennepohl P, DeBeer S. Introducing SpectraFit: An Open-Source Tool for Interactive Spectral Analysis. ACS OMEGA 2024; 9:23252-23265. [PMID: 38854548 PMCID: PMC11155667 DOI: 10.1021/acsomega.3c09262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 05/05/2024] [Accepted: 05/10/2024] [Indexed: 06/11/2024]
Abstract
In chemistry, analyzing spectra through peak fitting is a crucial task that helps scientists extract useful quantitative information about a sample's chemical composition or electronic structure. To make this process more efficient, we have developed a new open-source software tool called SpectraFit. This tool allows users to perform quick data fitting using expressions of distribution and linear functions through the command line interface (CLI) or Jupyter Notebook, which can run on Linux, Windows, and MacOS, as well as in a Docker container. As part of our commitment to good scientific practice, we have introduced an output file-locking system to ensure the accuracy and consistency of information. This system collects input data, results data, and the initial fitting model in a single file, promoting transparency, reproducibility, collaboration, and innovation. To demonstrate SpectraFit's user-friendly interface and the advantages of its output file-locking system, we are focusing on a series of previously published iron-sulfur dimers and their XAS spectra. We will show how to analyze the XAS spectra via CLI and in a Jupyter Notebook by simultaneously fitting multiple data sets using SpectraFit. Additionally, we will demonstrate how SpectraFit can be used as a black box and white box solution, allowing users to apply their own algorithms to engineer the data further. This publication, along with its Supporting Information and the Jupyter Notebook, serves as a tutorial to guide users through each step of the process. SpectraFit will streamline the peak fitting process and provide a convenient, standardized platform for users to share fitting models, which we hope will improve transparency and reproducibility in the field of spectroscopy.
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Affiliation(s)
- Anselm W. Hahn
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr 45470, Germany
| | - Joseph Zsombor-Pindera
- Department
of Chemistry, University of Calgary, Calgary, AB T2N 1N4, Canada
- Department
of Chemistry, The University of British
Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Pierre Kennepohl
- Department
of Chemistry, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Serena DeBeer
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr 45470, Germany
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2
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Yakovlev AG, Taisova AS. Quenching of bacteriochlorophyll a triplet state by carotenoids in the chlorosome baseplate of green bacterium Chloroflexus aurantiacus. Phys Chem Chem Phys 2024; 26:8815-8823. [PMID: 38421198 DOI: 10.1039/d4cp00287c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
To capture weak light fluxes, green photosynthetic bacteria have unique structures - chlorosomes, consisting of 104-5 molecules of bacteriochlorophyll (BChl) c, d, e. Chlorosomes are attached to the cytoplasmic membrane through the baseplate, a paracrystalline protein structure containing BChl a and carotenoids (Car). The most important function of Car is the quenching of triplet states of BChl, which prevents the formation of singlet oxygen and thereby provides photoprotection. In our work, we studied the dynamics of the triplet states of BChl a and Car in the baseplate of Chloroflexus aurantiacus chlorosomes using picosecond differential spectroscopy. BChl a of the baseplate was excited into the Qy band at 810 nm, and the corresponding absorption changes were recorded in the range of 420-880 nm. It was found that the formation of the Car triplet state occurs in ∼1.3 ns, which is ∼3 times faster than the formation of this state in the peripheral antenna of C. aurantiacus according to literature data. The Car triplet state was recorded by the characteristic absorption band T1 → Tn at ∼550 nm. Simultaneously with the appearance of absorption T1 → Tn, there was a bleaching of the singlet absorption of Car in the region of 400-500 nm. Theoretical modeling made it possible to estimate the characteristic time of formation of the triplet state of BChl a as ∼0.5 ns. It is shown that the experimental data are well described by the sequential scheme of formation and quenching of the BChl a triplet state: BChl a* → BChl aT → CarT. Thus, carotenoids from green bacteria effectively protect the baseplate from possible damage by singlet oxygen.
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Affiliation(s)
- Andrei G Yakovlev
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, Moscow 119991, Russian Federation.
| | - Alexandra S Taisova
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, Moscow 119991, Russian Federation.
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3
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Alster J, Bína D, Charvátová K, Lokstein H, Pšenčík J. Direct observation of triplet energy transfer between chlorophylls and carotenoids in the core antenna of photosystem I from Thermosynechococcus elongatus. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149016. [PMID: 37832862 DOI: 10.1016/j.bbabio.2023.149016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/29/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023]
Abstract
Quenching of chlorophyll triplet states by carotenoids is an essential photoprotective process, which prevents formation of reactive singlet oxygen in photosynthetic light-harvesting complexes. The process is usually very efficient in oxygenic organisms under physiological conditions, thus preventing any observable accumulation of chlorophyll triplets. However, it subsequently prevents also the determination of the triplet transfer rate. Here we report results of nanosecond transient absorption spectroscopy on photosystem I core complexes, where a major part of chlorophyll a triplet states (~60 %) accumulates on a nanosecond time scale at ambient temperature. As a consequence, the triplet energy transfer could be resolved and the transfer time was determined to be about 24 ns. A smaller fraction of chlorophyll a triplet states (~40 %) is quenched with a faster rate, which could not be determined. Our analysis indicates that these chlorophylls are in direct contact with carotenoids. The overall chlorophyll triplet yield in the core antenna was estimated to be ~0.3 %, which is a value two orders of magnitude smaller than in most other photosynthetic light-harvesting complexes. This explains why slower quenching of chlorophyll triplet states is sufficient for photoprotection of photosystem I. Nevertheless, the core antenna of photosystem I represents one of only few photosynthetic complexes of oxygenic organisms in which the quenching rate of the majority of chlorophyll triplets can be directly monitored under physiological temperature.
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Affiliation(s)
- J Alster
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - D Bína
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic; Biology Centre, Czech Academy of Science, České Budějovice, Czech Republic
| | - K Charvátová
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - H Lokstein
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - J Pšenčík
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic.
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4
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Kwok ACM, Leung SK, Wong JTY. DNA:RNA Hybrids Are Major Dinoflagellate Minicircle Molecular Types. Int J Mol Sci 2023; 24:ijms24119651. [PMID: 37298602 DOI: 10.3390/ijms24119651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 05/30/2023] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
Peridinin-containing dinoflagellate plastomes are predominantly encoded in nuclear genomes, with less than 20 essential chloroplast proteins carried on "minicircles". Each minicircle generally carries one gene and a short non-coding region (NCR) with a median length of approximately 400-1000 bp. We report here differential nuclease sensitivity and two-dimensional southern blot patterns, suggesting that dsDNA minicircles are in fact the minor forms, with substantial DNA:RNA hybrids (DRHs). Additionally, we observed large molecular weight intermediates, cell-lysate-dependent NCR secondary structures, multiple bidirectional predicted ssDNA structures, and different southern blot patterns when probed with different NCR fragments. In silico analysis suggested the existence of substantial secondary structures with inverted repeats (IR) and palindrome structures within the initial ~650 bp of the NCR sequences, in accordance with conversion event(s) outcomes with PCR. Based on these findings, we propose a new transcription-templating-translation model, which is associated with cross-hopping shift intermediates. Since dinoflagellate chloroplasts are cytosolic and lack nuclear envelope breakdown, the dynamic DRH minicircle transport could have contributed to the spatial-temporal dynamics required for photosystem repair. This represents a paradigm shift from the previous understanding of "minicircle DNAs" to a "working plastome", which will have significant implications for its molecular functionality and evolution.
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Affiliation(s)
- Alvin Chun Man Kwok
- Division of Life Science, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Siu Kai Leung
- Division of Life Science, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Joseph Tin Yum Wong
- Division of Life Science, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
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5
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Biswas S, Niedzwiedzki DM, Pakrasi HB. Energy dissipation efficiency in the CP43 assembly intermediate complex of photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148982. [PMID: 37146928 DOI: 10.1016/j.bbabio.2023.148982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/10/2023] [Accepted: 04/20/2023] [Indexed: 05/07/2023]
Abstract
Photosystem II in oxygenic organisms is a large membrane bound rapidly turning over pigment protein complex. During its biogenesis, multiple assembly intermediates are formed, including the CP43-preassembly complex (pCP43). To understand the energy transfer dynamics in pCP43, we first engineered a His-tagged version of the CP43 in a CP47-less strain of the cyanobacterium Synechocystis 6803. Isolated pCP43 from this engineered strain was subjected to advanced spectroscopic analysis to evaluate its excitation energy dissipation characteristics. These included measurements of steady-state absorption and fluorescence emission spectra for which correlation was tested with Stepanov relation. Comparison of fluorescence excitation and absorptance spectra determined that efficiency of energy transfer from β-carotene to chlorophyll a is 39 %. Time-resolved fluorescence images of pCP43-bound Chl a were recorded on streak camera, and fluorescence decay dynamics were evaluated with global fitting. These demonstrated that the decay kinetics strongly depends on temperature and buffer used to disperse the protein sample and fluorescence decay lifetime was estimated in 3.2-5.7 ns time range, depending on conditions. The pCP43 complex was also investigated with femtosecond and nanosecond time-resolved absorption spectroscopy upon excitation of Chl a and β-carotene to reveal pathways of singlet excitation relaxation/decay, Chl a triplet dynamics and Chl a → β-carotene triplet state sensitization process. The latter demonstrated that Chl a triplet in the pCP43 complex is not efficiently quenched by carotenoids. Finally, detailed kinetic analysis of the rise of the population of β-carotene triplets determined that the time constant of the carotenoid triplet sensitization is 40 ns.
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Affiliation(s)
- Sandeep Biswas
- Department of Biology, Washington University, St. Louis, MO 63130, USA.
| | - Dariusz M Niedzwiedzki
- Center for Solar Energy and Energy Storage, Washington University, St. Louis, MO 63130, USA; Department of Energy, Environmental & Chemical Engineering, Washington University, St. Louis, MO 63130, USA.
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO 63130, USA.
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6
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Niedzwiedzki DM, Magdaong NCM, Su X, Adir N, Keren N, Liu H. Mass spectrometry and spectroscopic characterization of a tetrameric photosystem I supercomplex from Leptolyngbya ohadii, a desiccation-tolerant cyanobacterium. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148955. [PMID: 36708912 DOI: 10.1016/j.bbabio.2023.148955] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/06/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023]
Abstract
Cyanobacteria inhabiting desert biological soil crusts face the harsh conditions of the desert. They evolved a suite of strategies toward desiccation-hydration cycles mixed with high light irradiations, etc. In this study we purified and characterized the structure and function of Photosystem I (PSI) from Leptolyngbya ohadii, a desiccation-tolerant desert cyanobacterium. We discovered that PSI forms tetrameric (PSI-Tet) aggregate. We investigated it by using sucrose density gradient centrifugation, clear native PAGE, high performance liquid chromatography, mass spectrometry (MS), time-resolved fluorescence (TRF) and time-resolved transient absorption (TA) spectroscopy. MS analysis identified the presence of two PsaB and two PsaL proteins in PSI-Tet and uniquely revealed that PsaLs are N-terminally acetylated in contrast to non-modified PsaL in the trimeric PSI from Synechocystis sp. PCC 6803. Chlorophyll (Chl) a fluorescence decay profiles of the PSI-Tet performed at 77 K revealed two emission bands at ∼690 nm and 725 nm with the former appearing only at early delay time. The main fluorescence emission peak, associated with emission from the low energy Chls a, decays within a few nanoseconds. TA studies demonstrated that the 725 nm emission band is associated with low energy Chls a with absorption band clearly resolved at ∼710 nm at 77 K. In summary, our work suggests that the heterogenous composition of PsaBs and PsaL in PSI-Tet is related with the adaptation mechanisms needed to cope with stressful conditions under which this bacterium naturally grows.
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Affiliation(s)
- Dariusz M Niedzwiedzki
- Center for Solar Energy and Energy Storage, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Energy Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
| | | | - Xinyang Su
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Noam Adir
- Schulich Faculty of Chemistry, Technion, Israel Institute of Technology, Hafai, Israel
| | - Nir Keren
- Department of Plant & Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Haijun Liu
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.
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7
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Niedzwiedzki DM, Magdaong NCM, Su X, Liu H. Biochemical and spectroscopic characterizations of the oligomeric antenna of the coral symbiotic Symbiodiniaceae Fugacium kawagutii. PHOTOSYNTHESIS RESEARCH 2022; 154:113-124. [PMID: 36070061 DOI: 10.1007/s11120-022-00951-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Light-harvesting antennas in photosynthesis capture light energy and transfer it to the reaction centers (RCs) where photochemistry takes place. The sustainable growth of the reef-building corals relies on a constant supply of the photosynthates produced by the endosymbiotic dinoflagellate, belonging to the family of Symbiodiniaceae. The antenna system in this group consists of the water-soluble peridinin-chlorophyll a-protein (PCP) and the intrinsic membrane chlorophyll a-chlorophyll c2-peridinin protein complex (acpPC). In this report, a nonameric acpPC is reported in a dinoflagellate, Fugasium kawagutii (formerly Symbiodinium kawagutii sp. CS-156). We found that extensive biochemical purification altered the oligomerization states of the initially isolated nonameric acpPC. The excitation energy transfer pathways in the acpPC nonamer and its variants were studied using time-resolved fluorescence and time-resolved absorption spectroscopic techniques at 77 K. Compared to the well-characterized trimeric acpPC, the nonameric acpPC contains an 11 nm red-shifted terminal energy emitter and substantially altered excited state lifetimes of Chl a. The observed energetic overlap of the fluorescence terminal energy emitters with the absorption of RCs is hypothesized to enable efficient downhill excitation energy transfer. Additionally, the shortened Chl a fluorescence decay lifetime in the oligomeric acpPC indicate a protective self-relaxation strategy. We propose that the highly-oligomerized acpPC nonamer represents an intact functional unit in the Symbiodiniaceae thylakoid membrane. They perform efficient excitation energy transfer (to RCs), and are under manageable regulations in favor of photoprotection.
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Affiliation(s)
- Dariusz M Niedzwiedzki
- Center for Solar Energy and Energy Storage, Washington University in St. Louis, St. Louis, MO, 63130, USA.
- Department of Energy Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA.
| | | | - Xinyang Su
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Haijun Liu
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.
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8
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Biswas S, Niedzwiedzki DM, Pakrasi HB. Introduction of cysteine-mediated quenching in the CP43 protein of photosystem II builds resilience to high-light stress in a cyanobacterium. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148580. [PMID: 35654167 DOI: 10.1016/j.bbabio.2022.148580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 05/16/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Photosystem (PS) II is prone to photodamage both as a direct consequence of light, and indirectly by producing reactive oxygen species. Engineering high-light tolerance in cyanobacteria with minimal impact on PSII function is desirable in synthetic biology. IsiA, a CP43 homolog found exclusively in cyanobacteria, can dissipate excess light energy. We have recently determined that the sole cysteine residue of IsiA in Synechocystis sp. PCC 6803 has a critical role in non-photochemical quenching. Similar cysteine-mediated energy quenching has also been observed in green‑sulfur bacteria. Sequence analysis of IsiA and CP43 aligns cysteine 260 of IsiA with valine 277 of CP43 in Synechocystis sp. PCC 6803. In the current study, we explore the impact of replacing valine 277 of CP43 to a cysteine on growth, PSII activity and high-light tolerance. Our results imply a decline in the PSII output for the mutant (CP43V277C) presumably due to the dissipation of absorbed light energy by cysteine. Spectroscopic analysis of isolated PSII from this mutant strain also suggests a delayed transfer of excitation energy from CP43-associated chlorophyll a to PSII reaction center. The mutation makes the PSII high-light tolerant and provides a small advantage in growth under high-light conditions. This previously unexplored strategy to engineer high-light tolerance could be a step further towards developing cyanobacterial cells as biofactories.
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Affiliation(s)
- Sandeep Biswas
- Department of Biology, Washington University, St. Louis, MO 63130, USA.
| | - Dariusz M Niedzwiedzki
- Center for Solar Energy and Energy Storage, Washington University, St. Louis, MO 63130, USA; Department of Energy, Environmental & Chemical Engineering, Washington University, St. Louis, MO 63130, USA.
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO 63130, USA.
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9
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Abstract
Oxygenic photosynthetic organisms have evolved a multitude of mechanisms for protection against high-light stress. IsiA, a chlorophyll a-binding cyanobacterial protein, serves as an accessory antenna complex for photosystem I. Intriguingly, IsiA can also function as an independent pigment protein complex in the thylakoid membrane and facilitate the dissipation of excess energy, providing photoprotection. The molecular basis of the IsiA-mediated excitation quenching mechanism remains poorly understood. In this study, we demonstrate that IsiA uses a novel cysteine-mediated process to quench excitation energy. The single cysteine in IsiA in the cyanobacterium Synechocystis sp. strain PCC 6803 was converted to a valine. Ultrafast fluorescence spectroscopic analysis showed that this single change abolishes the excitation energy quenching ability of IsiA, thus providing direct evidence of the crucial role of this cysteine residue in energy dissipation from excited chlorophylls. Under stress conditions, the mutant cells exhibited enhanced light sensitivity, indicating that the cysteine-mediated quenching process is critically important for photoprotection.
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10
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A photosynthetic antenna complex foregoes unity carotenoid-to-bacteriochlorophyll energy transfer efficiency to ensure photoprotection. Proc Natl Acad Sci U S A 2020; 117:6502-6508. [PMID: 32139606 DOI: 10.1073/pnas.1920923117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Carotenoids play a number of important roles in photosynthesis, primarily providing light-harvesting and photoprotective energy dissipation functions within pigment-protein complexes. The carbon-carbon double bond (C=C) conjugation length of carotenoids (N), generally between 9 and 15, determines the carotenoid-to-(bacterio)chlorophyll [(B)Chl] energy transfer efficiency. Here we purified and spectroscopically characterized light-harvesting complex 2 (LH2) from Rhodobacter sphaeroides containing the N = 7 carotenoid zeta (ζ)-carotene, not previously incorporated within a natural antenna complex. Transient absorption and time-resolved fluorescence show that, relative to the lifetime of the S1 state of ζ-carotene in solvent, the lifetime decreases ∼250-fold when ζ-carotene is incorporated within LH2, due to transfer of excitation energy to the B800 and B850 BChls a These measurements show that energy transfer proceeds with an efficiency of ∼100%, primarily via the S1 → Qx route because the S1 → S0 fluorescence emission of ζ-carotene overlaps almost perfectly with the Qx absorption band of the BChls. However, transient absorption measurements performed on microsecond timescales reveal that, unlike the native N ≥ 9 carotenoids normally utilized in light-harvesting complexes, ζ-carotene does not quench excited triplet states of BChl a, likely due to elevation of the ζ-carotene triplet energy state above that of BChl a These findings provide insights into the coevolution of photosynthetic pigments and pigment-protein complexes. We propose that the N ≥ 9 carotenoids found in light-harvesting antenna complexes represent a vital compromise that retains an acceptable level of energy transfer from carotenoids to (B)Chls while allowing acquisition of a new, essential function, namely, photoprotective quenching of harmful (B)Chl triplets.
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11
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Triplet state quenching of bacteriochlorophyll c aggregates in a protein-free environment of a chlorosome interior. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2019.110542] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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A novel chlorophyll protein complex in the repair cycle of photosystem II. Proc Natl Acad Sci U S A 2019; 116:21907-21913. [PMID: 31594847 DOI: 10.1073/pnas.1909644116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In oxygenic photosynthetic organisms, photosystem II (PSII) is a unique membrane protein complex that catalyzes light-driven oxidation of water. PSII undergoes frequent damage due to its demanding photochemistry. It must undergo a repair and reassembly process following photodamage, many facets of which remain unknown. We have discovered a PSII subcomplex that lacks 5 key PSII core reaction center polypeptides: D1, D2, PsbE, PsbF, and PsbI. This pigment-protein complex does contain the PSII core antenna proteins CP47 and CP43, as well as most of their associated low molecular mass subunits, and the assembly factor Psb27. Immunoblotting, mass spectrometry, and ultrafast spectroscopic results support the absence of a functional reaction center in this complex, which we call the "no reaction center" complex (NRC). Analytical ultracentrifugation and clear native PAGE analysis show that NRC is a stable pigment-protein complex and not a mixture of free CP47 and CP43 proteins. NRC appears in higher abundance in cells exposed to high light and impaired protein synthesis, and genetic deletion of PsbO on the PSII luminal side results in an increased NRC population, indicative that NRC forms in response to photodamage as part of the PSII repair process. Our finding challenges the current model of the PSII repair cycle and implies an alternative PSII repair strategy. Formation of this complex may maximize PSII repair economy by preserving intact PSII core antennas in a single complex available for PSII reassembly, minimizing the risk of randomly diluting multiple recycling components in the thylakoid membrane following a photodamage event.
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13
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Ho MY, Niedzwiedzki DM, MacGregor-Chatwin C, Gerstenecker G, Hunter CN, Blankenship RE, Bryant DA. Extensive remodeling of the photosynthetic apparatus alters energy transfer among photosynthetic complexes when cyanobacteria acclimate to far-red light. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1861:148064. [PMID: 31421078 DOI: 10.1016/j.bbabio.2019.148064] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 06/26/2019] [Accepted: 08/09/2019] [Indexed: 01/25/2023]
Abstract
Some cyanobacteria remodel their photosynthetic apparatus by a process known as Far-Red Light Photoacclimation (FaRLiP). Specific subunits of the phycobilisome (PBS), photosystem I (PSI), and photosystem II (PSII) complexes produced in visible light are replaced by paralogous subunits encoded within a conserved FaRLiP gene cluster when cells are grown in far-red light (FRL; λ = 700-800 nm). FRL-PSII complexes from the FaRLiP cyanobacterium, Synechococcus sp. PCC 7335, were purified and shown to contain Chl a, Chl d, Chl f, and pheophytin a, while FRL-PSI complexes contained only Chl a and Chl f. The spectroscopic properties of purified photosynthetic complexes from Synechococcus sp. PCC 7335 were determined individually, and energy transfer kinetics among PBS, PSII, and PSI were analyzed by time-resolved fluorescence (TRF) spectroscopy. Direct energy transfer from PSII to PSI was observed in cells (and thylakoids) grown in red light (RL), and possible routes of energy transfer in both RL- and FRL-grown cells were inferred. Three structural arrangements for RL-PSI were observed by atomic force microscopy of thylakoid membranes, but only arrays of trimeric FRL-PSI were observed in thylakoids from FRL-grown cells. Cells grown in FRL synthesized the FRL-specific complexes but also continued to synthesize some PBS and PSII complexes identical to those produced in RL. Although the light-harvesting efficiency of photosynthetic complexes produced in FRL might be lower in white light than the complexes produced in cells acclimated to white light, the FRL-complexes provide cells with the flexibility to utilize both visible and FRL to support oxygenic photosynthesis. This article is part of a Special Issue entitled Light harvesting, edited by Dr. Roberta Croce.
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Affiliation(s)
- Ming-Yang Ho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA; Intercollege Graduate Program in Plant Biology, The Pennsylvania State University, University Park, PA, USA
| | - Dariusz M Niedzwiedzki
- Department of Energy, Environmental & Chemical Engineering and Center for Solar Energy and Energy Storage, Washington University, St. Louis, MO, USA
| | | | - Gary Gerstenecker
- Department of Energy, Environmental & Chemical Engineering and Center for Solar Energy and Energy Storage, Washington University, St. Louis, MO, USA
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Robert E Blankenship
- Department of Energy, Environmental & Chemical Engineering and Center for Solar Energy and Energy Storage, Washington University, St. Louis, MO, USA; Departments of Biology and Chemistry, Washington University, St. Louis, MO, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA; Intercollege Graduate Program in Plant Biology, The Pennsylvania State University, University Park, PA, USA; Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
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14
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Niedzwiedzki DM, Wolf BM, Blankenship RE. Excitation energy transfer in the far-red absorbing violaxanthin/vaucheriaxanthin chlorophyll a complex from the eustigmatophyte alga FP5. PHOTOSYNTHESIS RESEARCH 2019; 140:337-354. [PMID: 30701484 DOI: 10.1007/s11120-019-00615-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/10/2019] [Indexed: 06/09/2023]
Abstract
This work highlights spectroscopic investigations on a new representative of photosynthetic antenna complexes in the LHC family, a putative violaxanthin/vaucheriaxanthin chlorophyll a (VCP) antenna complex from a freshwater Eustigmatophyte alga FP5. A representative VCP-like complex, named as VCP-B3 was studied with both static and time-resolved spectroscopies with the aim of obtaining a deeper understanding of excitation energy migration within the pigment array of the complex. Compared to other VCP representatives, the absorption spectrum of the VCP-B3 is strongly altered in the range of the chlorophyll a Qy band, and is substantially red-shifted with the longest wavelength absorption band at 707 nm at 77 K. VCP-B3 shows a moderate xanthophyll-to-chlorophyll a efficiency of excitation energy transfer in the 50-60% range, 20-30% lower from comparable VCP complexes from other organisms. Transient absorption studies accompanied by detailed data fitting and simulations support the idea that the xanthophylls that occupy the central part of the complex, complementary to luteins in the LHCII, are violaxanthins. Target analysis suggests that the primary route of xanthophyll-to-chlorophyll a energy transfer occurs via the xanthophyll S1 state.
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Affiliation(s)
- Dariusz M Niedzwiedzki
- Department of Energy, Environmental & Chemical Engineering and Center for Solar Energy and Energy Storage, Washington University in St Louis, St. Louis, MO, 63130, USA.
- Photosynthetic Antenna Research Center, Washington University in St Louis, St. Louis, MO, 63130, USA.
| | - Benjamin M Wolf
- Department of Biology, Washington University in St Louis, St. Louis, MO, 63130, USA
| | - Robert E Blankenship
- Department of Biology, Washington University in St Louis, St. Louis, MO, 63130, USA
- Department of Chemistry, Washington University in St Louis, St. Louis, MO, 63130, USA
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15
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Niedzwiedzki DM, Liu H, Blankenship RE. Excitation Energy Transfer in Intact CpcL-Phycobilisomes from Synechocystis sp. PCC 6803. J Phys Chem B 2019; 123:4695-4704. [PMID: 31042029 DOI: 10.1021/acs.jpcb.9b02696] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work highlights spectroscopic studies performed on a CpcL-phycobilisome (CpcL-PBS) light-harvesting complex from cyanobacterium Synechocystis sp. PCC 6803 ΔAB strain. The CpcL-PBS antenna has the form of a single rod made up exclusively of phycocyanins (PCs), a structure that is much simpler compared to the better known and broadly studied CpcG-PBS that consists of a cylindrical core with a set of protruding PC rods. Steady-state and time-resolved fluorescence studies demonstrated that the CpcL-PBS antenna comprises two spectral forms of phycocyanobilin (PCB), one emitting at 650 nm and a second emitting at 670 nm. The latter one presumably serves as the so-called terminal energy emitter without allophycocyanin. Studies of excitation energy migration between those two PCB forms demonstrated that even small buffer alterations, commonly applied by spectroscopists to tweak buffers to be more friendly for a certain type of spectroscopy, may lead to very different experimental outcomes and, in consequence, to differences in models of excitation migration pathway in this antenna complex.
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16
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Niedzwiedzki DM, Bar-Zvi S, Blankenship RE, Adir N. Mapping the excitation energy migration pathways in phycobilisomes from the cyanobacterium Acaryochloris marina. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:286-296. [PMID: 30703363 DOI: 10.1016/j.bbabio.2019.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/17/2018] [Accepted: 01/25/2019] [Indexed: 02/06/2023]
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17
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Magdaong NCM, Niedzwiedzki DM, Saer RG, Goodson C, Blankenship RE. Excitation energy transfer kinetics and efficiency in phototrophic green sulfur bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1180-1190. [DOI: 10.1016/j.bbabio.2018.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/25/2018] [Accepted: 07/30/2018] [Indexed: 01/16/2023]
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Bar-Zvi S, Lahav A, Harris D, Niedzwiedzki DM, Blankenship RE, Adir N. Structural heterogeneity leads to functional homogeneity in A. marina phycocyanin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:544-553. [DOI: 10.1016/j.bbabio.2018.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/18/2018] [Accepted: 04/23/2018] [Indexed: 12/31/2022]
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Khoroshyy P, Bína D, Gardian Z, Litvín R, Alster J, Pšenčík J. Quenching of chlorophyll triplet states by carotenoids in algal light-harvesting complexes related to fucoxanthin-chlorophyll protein. PHOTOSYNTHESIS RESEARCH 2018; 135:213-225. [PMID: 28669083 DOI: 10.1007/s11120-017-0416-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/16/2017] [Indexed: 06/07/2023]
Abstract
We have used time-resolved absorption and fluorescence spectroscopy with nanosecond resolution to study triplet energy transfer from chlorophylls to carotenoids in a protective process that prevents the formation of reactive singlet oxygen. The light-harvesting complexes studied were isolated from Chromera velia, belonging to a group Alveolata, and Xanthonema debile and Nannochloropsis oceanica, both from Stramenopiles. All three light-harvesting complexes are related to fucoxanthin-chlorophyll protein, but contain only chlorophyll a and no chlorophyll c. In addition, they differ in the carotenoid content. This composition of the complexes allowed us to study the quenching of chlorophyll a triplet states by different carotenoids in a comparable environment. The triplet states of chlorophylls bound to the light-harvesting complexes were quenched by carotenoids with an efficiency close to 100%. Carotenoid triplet states were observed to rise with a ~5 ns lifetime and were spectrally and kinetically homogeneous. The triplet states were formed predominantly on the red-most chlorophylls and were quenched by carotenoids which were further identified or at least spectrally characterized.
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Affiliation(s)
- Petro Khoroshyy
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, 121 16, Prague 2, Czech Republic
| | - David Bína
- Biological Centre, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic
| | - Zdenko Gardian
- Biological Centre, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic
| | - Radek Litvín
- Biological Centre, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic
| | - Jan Alster
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, 121 16, Prague 2, Czech Republic
| | - Jakub Pšenčík
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, 121 16, Prague 2, Czech Republic.
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Magdaong NCM, Saer RG, Niedzwiedzki DM, Blankenship RE. Ultrafast Spectroscopic Investigation of Energy Transfer in Site-Directed Mutants of the Fenna-Matthews-Olson (FMO) Antenna Complex from Chlorobaculum tepidum. J Phys Chem B 2017; 121:4700-4712. [PMID: 28422512 DOI: 10.1021/acs.jpcb.7b01270] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ultrafast transient absorption (TA) and time-resolved fluorescence (TRF) spectroscopic studies were performed on several mutants of the bacteriochlorophyll (BChl) a-containing Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Chlorobaculum tepidum. These mutants were generated to perturb a particular BChl a site and determine its effects on the optical spectroscopic properties of the pigment-protein complex. Measurements conducted at 77 K under both oxidizing and reducing conditions revealed changes in the dynamics of the various spectral components as compared to the data set from wild-type FMO. TRF results show that under reducing conditions all FMO samples decay with a similar lifetime in the ∼2 ns range. The oxidized samples revealed varying fluorescence lifetimes of the terminal BChl a emitter, considerably shorter than those recorded for the reduced samples, indicating that the quenching mechanism in wild-type FMO is still present in the mutants. Global fitting of TA data yielded similar overall results, and in addition, the lifetimes of early decaying components were determined. Target analyses of TA data for select FMO samples generated kinetic models that better simulate the TA data. A comparison of the lifetime of excitonic components for all samples reveals that the mutations affect mainly the early kinetic components, but not that of the lowest energy exciton, which reflects the flexibility of energy transfer in FMO.
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Affiliation(s)
- Nikki Cecil M Magdaong
- Department of Biology, ‡Department of Chemistry, and §Photosynthetic Antenna Research Center, Washington University in Saint Louis , One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Rafael G Saer
- Department of Biology, ‡Department of Chemistry, and §Photosynthetic Antenna Research Center, Washington University in Saint Louis , One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Dariusz M Niedzwiedzki
- Department of Biology, ‡Department of Chemistry, and §Photosynthetic Antenna Research Center, Washington University in Saint Louis , One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Robert E Blankenship
- Department of Biology, ‡Department of Chemistry, and §Photosynthetic Antenna Research Center, Washington University in Saint Louis , One Brookings Drive, St. Louis, Missouri 63130, United States
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Chen HYS, Liberton M, Pakrasi HB, Niedzwiedzki DM. Reevaluating the mechanism of excitation energy regulation in iron-starved cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:249-258. [DOI: 10.1016/j.bbabio.2017.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/20/2016] [Accepted: 01/06/2017] [Indexed: 12/18/2022]
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22
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Niedzwiedzki DM, Tronina T, Liu H, Staleva H, Komenda J, Sobotka R, Blankenship RE, Polívka T. Carotenoid-induced non-photochemical quenching in the cyanobacterial chlorophyll synthase-HliC/D complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1430-1439. [PMID: 27133505 DOI: 10.1016/j.bbabio.2016.04.280] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 03/31/2016] [Accepted: 04/27/2016] [Indexed: 11/18/2022]
Abstract
Chl synthase (ChlG) is an important enzyme of the Chl biosynthetic pathway catalyzing attachment of phytol/geranylgeraniol tail to the chlorophyllide molecule. Here we have investigated the Flag-tagged ChlG (f.ChlG) in a complex with two different high-light inducible proteins (Hlips) HliD and HliC. The f.ChlG-Hlips complex binds a Chl a and three different carotenoids, β-carotene, zeaxanthin and myxoxanthophyll. Application of ultrafast time-resolved absorption spectroscopy performed at room and cryogenic temperatures revealed excited-state dynamics of complex-bound pigments. After excitation of Chl a in the complex, excited Chl a is efficiently quenched by a nearby carotenoid molecule via energy transfer from the Chl a Qy state to the carotenoid S1 state. The kinetic analysis of the spectroscopic data revealed that quenching occurs with a time constant of ~2ps and its efficiency is temperature independent. Even though due to its long conjugation myxoxanthophyll appears to be energetically best suited for role of Chl a quencher, based on comparative analysis and spectroscopic data we propose that β-carotene bound to Hlips acts as the quencher rather than myxoxanthophyll and zeaxanthin, which are bound at the f.ChlG and Hlips interface. The S1 state lifetime of the quencher has been determined to be 13ps at room temperature and 21ps at 77K. These results demonstrate that Hlips act as a conserved functional module that prevents photodamage of protein complexes during photosystem assembly or Chl biosynthesis.
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Affiliation(s)
- Dariusz M Niedzwiedzki
- Photosynthetic Antenna Research Center, Washington University in Saint Louis, 1 Brookings Drive, St. Louis, MO 63130, USA
| | - Tomasz Tronina
- Department of Chemistry, Wroclaw University of Environmental and Life Sciences, 50-375 Wroclaw, Poland
| | - Haijun Liu
- Photosynthetic Antenna Research Center, Washington University in Saint Louis, 1 Brookings Drive, St. Louis, MO 63130, USA; Department of Biology, Washington University in St. Louis, 1 Brookings, Drive. St. Louis, MO 63130, USA
| | - Hristina Staleva
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Josef Komenda
- Centre Algatech, Institute of Microbiology, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic
| | - Roman Sobotka
- Centre Algatech, Institute of Microbiology, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic
| | - Robert E Blankenship
- Photosynthetic Antenna Research Center, Washington University in Saint Louis, 1 Brookings Drive, St. Louis, MO 63130, USA; Department of Biology, Washington University in St. Louis, 1 Brookings, Drive. St. Louis, MO 63130, USA; Department of Chemistry, Washington University in St. Louis, 1 Brookings, Drive. St. Louis, MO 63130, USA
| | - Tomáš Polívka
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
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Kvíčalová Z, Alster J, Hofmann E, Khoroshyy P, Litvín R, Bína D, Polívka T, Pšenčík J. Triplet–triplet energy transfer from chlorophylls to carotenoids in two antenna complexes from dinoflagellate Amphidinium carterae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:341-9. [DOI: 10.1016/j.bbabio.2016.01.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/08/2016] [Accepted: 01/17/2016] [Indexed: 11/24/2022]
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24
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Greco JA, LaFountain AM, Kinashi N, Shinada T, Sakaguchi K, Katsumura S, Magdaong NCM, Niedzwiedzki DM, Birge RR, Frank HA. Spectroscopic Investigation of the Carotenoid Deoxyperidinin: Direct Observation of the Forbidden S0 → S1 Transition. J Phys Chem B 2016; 120:2731-44. [DOI: 10.1021/acs.jpcb.6b00439] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Jordan A. Greco
- Department
of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269-3060, United States
| | - Amy M. LaFountain
- Department
of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269-3060, United States
| | - Naoto Kinashi
- Graduate
School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Tetsuro Shinada
- Graduate
School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Kazuhiko Sakaguchi
- Graduate
School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shigeo Katsumura
- Graduate
School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Nikki Cecil M. Magdaong
- Department
of Biology, Washington University in Saint Louis, One Brookings
Drive, St. Louis, Missouri 63130, United States
| | - Dariusz M. Niedzwiedzki
- Photosynthetic
Antenna Research Center, Washington University in Saint Louis, One Brookings
Drive, St. Louis, Missouri 63130, United States
| | - Robert R. Birge
- Department
of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269-3060, United States
| | - Harry A. Frank
- Department
of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269-3060, United States
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25
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Jiang J, Zhang H, Lu X, Lu Y, Cuneo MJ, O'Neill HM, Urban V, Lo CS, Blankenship RE. Oligomerization state and pigment binding strength of the peridinin-Chl a-protein. FEBS Lett 2015; 589:2713-9. [PMID: 26241331 DOI: 10.1016/j.febslet.2015.07.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 07/13/2015] [Accepted: 07/20/2015] [Indexed: 11/28/2022]
Abstract
The peridinin-chlorophyll a-protein (PCP) is one of the major light harvesting complexes (LHCs) in photosynthetic dinoflagellates. We analyzed the oligomeric state of PCP isolated from the dinoflagellate Symbiodinium, which has received increasing attention in recent years because of its role in coral bleaching. Size-exclusion chromatography (SEC) and small angle neutron scattering (SANS) analysis indicated PCP exists as monomers. Native mass spectrometry (native MS) demonstrated two oligomeric states of PCP, with the monomeric PCP being dominant. The trimerization may not be necessary for PCP to function as a light-harvesting complex.
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Affiliation(s)
- Jing Jiang
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Hao Zhang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Xun Lu
- Center for Structural Molecular Biology, Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Yue Lu
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Matthew J Cuneo
- Center for Structural Molecular Biology, Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Hugh M O'Neill
- Center for Structural Molecular Biology, Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Volker Urban
- Center for Structural Molecular Biology, Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Cynthia S Lo
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Robert E Blankenship
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.
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Carbonera D, Di Valentin M, Spezia R, Mezzetti A. The unique photophysical properties of the Peridinin-Chlorophyll-α-Protein. Curr Protein Pept Sci 2015; 15:332-50. [PMID: 24678668 PMCID: PMC4030626 DOI: 10.2174/1389203715666140327111139] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 11/22/2013] [Accepted: 03/16/2014] [Indexed: 11/22/2022]
Abstract
Peridinin-Chlorophyll-a-Proteins (PCPs) are water-soluble light harvesting complexes from dinoflagellates.
They have unique light-harvesting and energy transfer properties which have been studied in details in the last 15 years.
This review aims to give an overview on all the main aspects of PCPs photophysics, with an emphasis on some aspects
which have not been reviewed in details so far, such as vibrational spectroscopy studies, theoretical calculations, and
magnetic resonance studies. A paragraph on the present development of PCPs towards technological applications is also
included.
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Affiliation(s)
| | | | | | - Alberto Mezzetti
- Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131 Padova, Italy.
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Roth MS. The engine of the reef: photobiology of the coral-algal symbiosis. Front Microbiol 2014; 5:422. [PMID: 25202301 PMCID: PMC4141621 DOI: 10.3389/fmicb.2014.00422] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 07/25/2014] [Indexed: 01/09/2023] Open
Abstract
Coral reef ecosystems thrive in tropical oligotrophic oceans because of the relationship between corals and endosymbiotic dinoflagellate algae called Symbiodinium. Symbiodinium convert sunlight and carbon dioxide into organic carbon and oxygen to fuel coral growth and calcification, creating habitat for these diverse and productive ecosystems. Light is thus a key regulating factor shaping the productivity, physiology, and ecology of the coral holobiont. Similar to all oxygenic photoautotrophs, Symbiodinium must safely harvest sunlight for photosynthesis and dissipate excess energy to prevent oxidative stress. Oxidative stress is caused by environmental stressors such as those associated with global climate change, and ultimately leads to breakdown of the coral-algal symbiosis known as coral bleaching. Recently, large-scale coral bleaching events have become pervasive and frequent threatening and endangering coral reefs. Because the coral-algal symbiosis is the biological engine producing the reef, the future of coral reef ecosystems depends on the ecophysiology of the symbiosis. This review examines the photobiology of the coral-algal symbiosis with particular focus on the photophysiological responses and timescales of corals and Symbiodinium. Additionally, this review summarizes the light environment and its dynamics, the vulnerability of the symbiosis to oxidative stress, the abiotic and biotic factors influencing photosynthesis, the diversity of the coral-algal symbiosis, and recent advances in the field. Studies integrating physiology with the developing "omics" fields will provide new insights into the coral-algal symbiosis. Greater physiological and ecological understanding of the coral-algal symbiosis is needed for protection and conservation of coral reefs.
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Affiliation(s)
- Melissa S. Roth
- Department of Plant and Microbial Biology, University of California BerkeleyBerkeley, CA, USA
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Kanazawa A, Blanchard GJ, Szabó M, Ralph PJ, Kramer DM. The site of regulation of light capture in Symbiodinium: Does the peridinin–chlorophyll a–protein detach to regulate light capture? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1227-34. [DOI: 10.1016/j.bbabio.2014.03.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 03/27/2014] [Accepted: 03/29/2014] [Indexed: 10/25/2022]
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