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Zazubovich V, Jankowiak R. High-Resolution Frequency-Domain Spectroscopic and Modeling Studies of Photosystem I (PSI), PSI Mutants and PSI Supercomplexes. Int J Mol Sci 2024; 25:3850. [PMID: 38612659 PMCID: PMC11011720 DOI: 10.3390/ijms25073850] [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: 02/23/2024] [Revised: 03/23/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
Photosystem I (PSI) is one of the two main pigment-protein complexes where the primary steps of oxygenic photosynthesis take place. This review describes low-temperature frequency-domain experiments (absorption, emission, circular dichroism, resonant and non-resonant hole-burned spectra) and modeling efforts reported for PSI in recent years. In particular, we focus on the spectral hole-burning studies, which are not as common in photosynthesis research as the time-domain spectroscopies. Experimental and modeling data obtained for trimeric cyanobacterial Photosystem I (PSI3), PSI3 mutants, and PSI3-IsiA18 supercomplexes are analyzed to provide a more comprehensive understanding of their excitonic structure and excitation energy transfer (EET) processes. Detailed information on the excitonic structure of photosynthetic complexes is essential to determine the structure-function relationship. We will focus on the so-called "red antenna states" of cyanobacterial PSI, as these states play an important role in photochemical processes and EET pathways. The high-resolution data and modeling studies presented here provide additional information on the energetics of the lowest energy states and their chlorophyll (Chl) compositions, as well as the EET pathways and how they are altered by mutations. We present evidence that the low-energy traps observed in PSI are excitonically coupled states with significant charge-transfer (CT) character. The analysis presented for various optical spectra of PSI3 and PSI3-IsiA18 supercomplexes allowed us to make inferences about EET from the IsiA18 ring to the PSI3 core and demonstrate that the number of entry points varies between sample preparations studied by different groups. In our most recent samples, there most likely are three entry points for EET from the IsiA18 ring per the PSI core monomer, with two of these entry points likely being located next to each other. Therefore, there are nine entry points from the IsiA18 ring to the PSI3 trimer. We anticipate that the data discussed below will stimulate further research in this area, providing even more insight into the structure-based models of these important cyanobacterial photosystems.
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Affiliation(s)
- Valter Zazubovich
- Department of Physics, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, KS 66506, USA
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Biswas S, Niedzwiedzki DM, Liberton M, Pakrasi HB. Phylogenetic and spectroscopic insights on the evolution of core antenna proteins in cyanobacteria. PHOTOSYNTHESIS RESEARCH 2023:10.1007/s11120-023-01046-6. [PMID: 37737529 DOI: 10.1007/s11120-023-01046-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 08/31/2023] [Indexed: 09/23/2023]
Abstract
Light harvesting by antenna systems is the initial step in a series of electron-transfer reactions in all photosynthetic organisms, leading to energy trapping by reaction center proteins. Cyanobacteria are an ecologically diverse group and are the simplest organisms capable of oxygenic photosynthesis. The primary light-harvesting antenna in cyanobacteria is the large membrane extrinsic pigment-protein complex called the phycobilisome. In addition, cyanobacteria have also evolved specialized membrane-intrinsic chlorophyll-binding antenna proteins that transfer excitation energy to the reaction centers of photosystems I and II (PSI and PSII) and dissipate excess energy through nonphotochemical quenching. Primary among these are the CP43 and CP47 proteins of PSII, but in addition, some cyanobacteria also use IsiA and the prochlorophyte chlorophyll a/b binding (Pcb) family of proteins. Together, these proteins comprise the CP43 family of proteins owing to their sequence similarity with CP43. In this article, we have revisited the evolution of these chlorophyll-binding antenna proteins by examining their protein sequences in parallel with their spectral properties. Our phylogenetic and spectroscopic analyses support the idea of a common ancestor for CP43, IsiA, and Pcb proteins, and suggest that PcbC might be a distant ancestor of IsiA. The similar spectral properties of CP47 and IsiA suggest a closer evolutionary relationship between these proteins compared to CP43.
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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 and Chemical Engineering, Washington University, St. Louis, MO, 63130, USA
| | - Michelle Liberton
- Department of Biology, Washington University, St. Louis, MO, 63130, USA
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO, 63130, USA.
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3
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Harris D, Toporik H, Schlau-Cohen GS, Mazor Y. Energetic robustness to large scale structural fluctuations in a photosynthetic supercomplex. Nat Commun 2023; 14:4650. [PMID: 37532717 PMCID: PMC10397321 DOI: 10.1038/s41467-023-40146-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 07/14/2023] [Indexed: 08/04/2023] Open
Abstract
Photosynthetic organisms transport and convert solar energy with near-unity quantum efficiency using large protein supercomplexes held in flexible membranes. The individual proteins position chlorophylls to tight tolerances considered critical for fast and efficient energy transfer. The variability in protein organization within the supercomplexes, and how efficiency is maintained despite variability, had been unresolved. Here, we report on structural heterogeneity in the 2-MDa cyanobacterial PSI-IsiA photosynthetic supercomplex observed using Cryo-EM, revealing large-scale variances in the positions of IsiA relative to PSI. Single-molecule measurements found efficient IsiA-to-PSI energy transfer across all conformations, along with signatures of transiently decoupled IsiA. Structure based calculations showed that rapid IsiA-to-PSI energy transfer is always maintained, and even increases by three-fold in rare conformations via IsiA-specific chls. We postulate that antennae design mitigates structural fluctuations, providing a mechanism for robust energy transfer in the flexible membrane.
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Affiliation(s)
- Dvir Harris
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Hila Toporik
- Biodesign Institute, School of Molecular Sciences, Arizona State University, Tempe, AZ, 85801, USA
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
- Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Gabriela S Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
| | - Yuval Mazor
- Biodesign Institute, School of Molecular Sciences, Arizona State University, Tempe, AZ, 85801, USA.
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA.
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4
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Reinot T, Khmelnitskiy A, Zazubovich V, Toporik H, Mazor Y, Jankowiak R. Frequency-Domain Spectroscopic Study of the Photosystem I Supercomplexes, Isolated IsiA Monomers, and the Intact IsiA Ring. J Phys Chem B 2022; 126:6891-6910. [PMID: 36065077 DOI: 10.1021/acs.jpcb.2c04829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The PSI3-IsiA18 supercomplex is one of the largest and most complicated assemblies in photosynthesis. The IsiA ring, composed of 18 IsiA monomers (IsiA18) surrounding the PSI trimer (PSI3), forms under iron-deficient conditions in cyanobacteria and acts as a peripheral antenna. Based on the supercomplex structure recently determined via cryo-EM imaging, we model various optical spectra of the IsiA monomers and IsiA18 ring. Comparison of the absorption and emission spectra of the isolated IsiA monomers and the full ring reveals that about 2.7 chlorophylls (Chls) are lost in the isolated IsiA monomers. The best fits for isolated monomers spectra are obtained assuming the absence of Chl 508 and Chl 517 and 70% loss of Chl 511. The best model describing all three hexamers and the entire ring suggests that the lowest energy pigments are Chls 511, 514, and 517. Based on the modeling results presented in this work, we conclude that there are most likely three entry points for EET from the IsiA6 hexamer to the PSI core monomer, with two of these entry points likely being located next to each other (i.e., nine entry points from IsiA18 to the PSI3 trimer). Finally, we show that excitation energy transfer inside individual monomers is fast (<2 ps at T = 5 K) and at least 20 times faster than intermonomer energy transfer.
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Affiliation(s)
| | | | - Valter Zazubovich
- Department of Physics, Concordia University, Montreal, H4B 1R6, Canada
| | - Hila Toporik
- School of Molecular Sciences and Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
| | - Yuval Mazor
- School of Molecular Sciences and Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
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Jia A, Zheng Y, Chen H, Wang Q. Regulation and Functional Complexity of the Chlorophyll-Binding Protein IsiA. Front Microbiol 2021; 12:774107. [PMID: 34867913 PMCID: PMC8635728 DOI: 10.3389/fmicb.2021.774107] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
As the oldest known lineage of oxygen-releasing photosynthetic organisms, cyanobacteria play the key roles in helping shaping the ecology of Earth. Iron is an ideal transition metal for redox reactions in biological systems. Cyanobacteria frequently encounter iron deficiency due to the environmental oxidation of ferrous ions to ferric ions, which are highly insoluble at physiological pH. A series of responses, including architectural changes to the photosynthetic membranes, allow cyanobacteria to withstand this condition and maintain photosynthesis. Iron-stress-induced protein A (IsiA) is homologous to the cyanobacterial chlorophyll (Chl)-binding protein, photosystem II core antenna protein CP43. IsiA is the major Chl-containing protein in iron-starved cyanobacteria, binding up to 50% of the Chl in these cells, and this Chl can be released from IsiA for the reconstruction of photosystems during the recovery from iron limitation. The pigment–protein complex (CPVI-4) encoded by isiA was identified and found to be expressed under iron-deficient conditions nearly 30years ago. However, its precise function is unknown, partially due to its complex regulation; isiA expression is induced by various types of stresses and abnormal physiological states besides iron deficiency. Furthermore, IsiA forms a range of complexes that perform different functions. In this article, we describe progress in understanding the regulation and functions of IsiA based on laboratory research using model cyanobacteria.
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Affiliation(s)
- Anqi Jia
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Yanli Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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6
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Reinot T, Jassas M, Kell A, Casazza AP, Santabarbara S, Jankowiak R. On wavelength-dependent exciton lifetime distributions in reconstituted CP29 antenna of the photosystem II and its site-directed mutants. J Chem Phys 2021; 154:085101. [PMID: 33639775 DOI: 10.1063/5.0038217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To provide more insight into the excitonic structure and exciton lifetimes of the wild type (WT) CP29 complex of photosystem II, we measured high-resolution (low temperature) absorption, emission, and hole burned spectra for the A2 and B3 mutants, which lack chlorophylls a612 and b614 (Chls), respectively. Experimental and modeling results obtained for the WT CP29 and A2/B3 mutants provide new insight on the mutation-induced changes at the molecular level and shed more light on energy transfer dynamics. Simulations of the A2 and B3 optical spectra, using the second-order non-Markovian theory, and comparison with improved fits of WT CP29 optical spectra provide more insight into their excitonic structure, mutation induced changes, and frequency-dependent distributions of exciton lifetimes (T1). A new Hamiltonian obtained for WT CP29 reveals that deletion of Chls a612 or b614 induces changes in the site energies of all remaining Chls. Hamiltonians obtained for A2 and B3 mutants are discussed in the context of the energy landscape of chlorophylls, excitonic structure, and transfer kinetics. Our data suggest that the lowest exciton states in A2 and B3 mutants are contributed by a611(57%), a610(17%), a615(15%) and a615(58%), a611(20%), a612(15%) Chls, respectively, although other compositions of lowest energy states are also discussed. Finally, we argue that the calculated exciton decay times are consistent with both the hole-burning and recent transient absorption measurements. Wavelength-dependent T1 distributions offer more insight into the interpretation of kinetic traces commonly described by discrete exponentials in global analysis/global fitting of transient absorption experiments.
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Affiliation(s)
- Tonu Reinot
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, USA
| | - Mahboobe Jassas
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, USA
| | - Adam Kell
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, USA
| | - Anna Paola Casazza
- Istituto di Biologia e Biotecnologia Agraria, C.N.R., Via Bassini 15, 20133 Milano, Italy
| | - Stefano Santabarbara
- Photosynthesis Research Unit, Centro Studi sulla Biologia Cellulare e Molecolare delle Piante, C.N.R., Milano, Italy
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, USA
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7
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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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8
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Khmelnitskiy A, Toporik H, Mazor Y, Jankowiak R. On the Red Antenna States of Photosystem I Mutants from Cyanobacteria Synechocystis PCC 6803. J Phys Chem B 2020; 124:8504-8515. [DOI: 10.1021/acs.jpcb.0c05201] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anton Khmelnitskiy
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Hila Toporik
- School of Molecular Sciences and The Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Yuval Mazor
- School of Molecular Sciences and The Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
- Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
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9
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Jassas M, Goodson C, Blankenship RE, Jankowiak R, Kell A. On Excitation Energy Transfer within the Baseplate BChl a-CsmA Complex of Chloroflexus aurantiacus. J Phys Chem B 2019; 123:9786-9791. [PMID: 31660744 DOI: 10.1021/acs.jpcb.9b08043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently, a hybrid approach combining solid-state NMR spectroscopy and cryo-electron microscopy showed that the baseplate in green sulfur bacterium Chlorobaculum tepidum is a 2D lattice of BChl a-CsmA dimers [Nielsen, J. T.; et al., Nat. Commun. 2016, 7, 12454-12465]. While the existence of the BChl a-CsmA subunit was previously known, the proposed orientations of the BChl a pigments had only been elucidated from spectral data up to this point. Regarding the electronic structure of the baseplate, two models have been proposed. 2D electronic spectroscopy data were interpreted as revealing that at least four excitonically coupled BChl a might be in close contact. Conversely, spectral hole burning data suggested that the lowest energy state was localized, yet additional states are sometimes observed because of the presence of the Fenna-Matthews-Olson (FMO) antenna protein. To solve this conundrum, this work studies the chlorosome-baseplate complex from Chloroflexus aurantiacus, which does not contain the FMO protein. The results confirm that in both C. tepidum and C. aurantiacus, excitation energy is transferred to a localized low-energy trap state near 818 nm with similar rates, most likely via exciton hopping.
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Affiliation(s)
| | - Carrie Goodson
- Departments of Biology and Chemistry , Washington University in Saint Louis , Saint Louis , Missouri 63130 , United States
| | - Robert E Blankenship
- Departments of Biology and Chemistry , Washington University in Saint Louis , Saint Louis , Missouri 63130 , United States
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10
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Khmelnitskiy A, Williams JC, Allen JP, Jankowiak R. Influence of Hydrogen Bonds on the Electron-Phonon Coupling Strength/Marker Mode Structure and Charge Separation Rates in Reaction Centers from Rhodobacter sphaeroides. J Phys Chem B 2019; 123:8717-8726. [PMID: 31539255 DOI: 10.1021/acs.jpcb.9b08388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Low-temperature persistent and transient hole-burning (HB) spectra are presented for the triple hydrogen-bonded L131LH + M160LH + M197FH mutant of Rhodobacter sphaeroides. These spectra expose the heterogeneous nature of the P-, B-, and H-bands, consistent with a distribution of electron transfer (ET) times and excitation energy transfer (EET) rates. Transient P+QA- holes are observed for fast (tens of picoseconds or faster) ET times and reveal strong coupling to phonons and marker mode(s), while the persistent holes are bleached in a fraction of reaction centers with long-lived excited states characterized by much weaker electron-phonon coupling. Exposed differences in electron-phonon coupling strength, as well as a different coupling to the marker mode(s), appear to affect the ET times. Both resonantly and nonresonantly burned persistent HB spectra show weak blue- (∼150 cm-1) and large, red-shifted (∼300 cm-1) antiholes of the P band. Slower EET times from the H- and B-bands to the special pair dimer provide new insight on the influence of hydrogen bonds on mutation-induced heterogeneity.
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Affiliation(s)
| | - JoAnn C Williams
- School of Molecular Sciences , Arizona State University , Tempe , Arizona 85287 , United States
| | - James P Allen
- School of Molecular Sciences , Arizona State University , Tempe , Arizona 85287 , United States
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11
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Khmelnitskiy A, Reinot T, Jankowiak R. Mixed Upper Exciton State of the Special Pair in Bacterial Reaction Centers. J Phys Chem B 2019; 123:852-859. [PMID: 30624937 DOI: 10.1021/acs.jpcb.8b12542] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Excitonic interactions between two closely separated bacteriochlorophyll a molecules (BChls) in the special pair of the reaction center (RC) of purple bacteria determine the positions and relative oscillator strengths of its two excitonic components. While the absorption of the lower excitonic band is well-defined, the position and the intensity of the upper excitonic band ( PY+) are still under debate. Recent 77 K two-dimensional electronic spectroscopy data on Rba. capsulatus suggested that the PY+ component absorbs at ∼840 nm, i.e., at a significantly lower energy than previously suggested. In the present work, we argue that the PY+ state is mixed with the excited states of the accessory BChls ( B*/ P Y+) leading to excitons contributing to the 785-825 nm spectral region which is consistent with previously published data. This conclusion is based on hole-burning/linear dichroism data and modeling studies of the excitonic structure of the RC using a non-Markovian reduced density matrix approach.
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12
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Khmelnitskiy A, Saer RG, Blankenship RE, Jankowiak R. Excitonic Energy Landscape of the Y16F Mutant of the Chlorobium tepidum Fenna-Matthews-Olson (FMO) Complex: High Resolution Spectroscopic and Modeling Studies. J Phys Chem B 2018; 122:3734-3743. [PMID: 29554425 DOI: 10.1021/acs.jpcb.7b11763] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We report high-resolution (low-temperature) absorption, emission, and nonresonant/resonant hole-burned (HB) spectra and results of excitonic calculations using a non-Markovian reduced density matrix theory (with an improved algorithm for parameter optimization in heterogeneous samples) obtained for the Y16F mutant of the Fenna-Matthews-Olson (FMO) trimer from the green sulfur bacterium Chlorobium tepidum. We show that the Y16F mutant is a mixture of FMO complexes with three independent low-energy traps (located near 817, 821, and 826 nm), in agreement with measured composite emission and HB spectra. Two of these traps belong to mutated FMO subpopulations characterized by significantly modified low-energy excitonic states. Hamiltonians for the two major subpopulations (Sub821 and Sub817) provide new insight into extensive changes induced by the single-point mutation in the vicinity of BChl 3 (where tyrosine Y16 was replaced with phenylalanine F16). The average decay time(s) from the higher exciton state(s) in the Y16F mutant depends on frequency and occurs on a picosecond time scale.
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Affiliation(s)
| | - Rafael G Saer
- Departments of Biology and Chemistry , Washington University in St. Louis , Saint Louis , Missouri 63130 , United States
| | - Robert E Blankenship
- Departments of Biology and Chemistry , Washington University in St. Louis , Saint Louis , Missouri 63130 , United States
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13
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Jassas M, Chen J, Khmelnitskiy A, Casazza AP, Santabarbara S, Jankowiak R. Structure-Based Exciton Hamiltonian and Dynamics for the Reconstituted Wild-type CP29 Protein Antenna Complex of the Photosystem II. J Phys Chem B 2018; 122:4611-4624. [DOI: 10.1021/acs.jpcb.8b00032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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14
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Khmelnitskiy A, Kell A, Reinot T, Saer RG, Blankenship RE, Jankowiak R. Energy landscape of the intact and destabilized FMO antennas from C. tepidum and the L122Q mutant: Low temperature spectroscopy and modeling study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:165-173. [DOI: 10.1016/j.bbabio.2017.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/23/2017] [Accepted: 11/27/2017] [Indexed: 12/21/2022]
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15
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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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16
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Ma F, Zhang X, Zhu X, Li T, Zhan J, Chen H, He C, Wang Q. Dynamic Changes of IsiA-Containing Complexes during Long-Term Iron Deficiency in Synechocystis sp. PCC 6803. MOLECULAR PLANT 2017; 10:143-154. [PMID: 27777125 DOI: 10.1016/j.molp.2016.10.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/05/2016] [Accepted: 10/13/2016] [Indexed: 05/26/2023]
Abstract
Iron stress-induced protein A (IsiA), a major chlorophyll-binding protein in the thylakoid membrane, is significantly induced under iron deficiency conditions. Using immunoblot analysis and 77 K fluorescence spectroscopy combined with sucrose gradient fractionation, we monitored dynamic changes of IsiA-containing complexes in Synechocystis sp. PCC 6803 during exposure to long-term iron deficiency. Within 3 days of exposure to iron deficiency conditions, the initially induced free IsiA proteins preferentially conjugated to PS I trimer to form IsiA18-PS I trimers, which serve as light energy collectors for efficiently transmitting energy to PS I. With prolonged iron deficiency, IsiA proteins assembled either into IsiA aggregates or into two other types of IsiA-PS I supercomplexes, namely IsiA-PS I high fluorescence supercomplex (IHFS) and IsiA-PS I low fluorescence supercomplex (ILFS). Further analysis revealed a role for IsiA as an energy dissipater in the IHFS and as an energy collector in the ILFS. The trimeric structure of PS I mediated by PsaL was found to be indispensable for the formation of IHFS/ILFS. Dynamic changes in IsiA-containing complexes in cyanobacteria during long-term iron deficiency may represent an adaptation to iron limitation stress for flexible light energy distribution, which balances electron transfer between PS I and PS II, thus minimizing photooxidative damage.
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Affiliation(s)
- Fei Ma
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Xin Zhang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Xi Zhu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Tianpei Li
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Jiao Zhan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Hui Chen
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Chenliu He
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Qiang Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China.
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Jankowiak R, Rancova O, Chen J, Kell A, Saer RG, Beatty JT, Abramavicius D. Mutation-Induced Changes in the Protein Environment and Site Energies in the (M)L214G Mutant of the Rhodobacter sphaeroides Bacterial Reaction Center. J Phys Chem B 2016; 120:7859-71. [PMID: 27458891 DOI: 10.1021/acs.jpcb.6b06151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This work focuses on the low-temperature (5 K) photochemical (transient) hole-burned (HB) spectra within the P870 absorption band, and their theoretical analysis, for the (M)L214G mutant of the photosynthetic Rhodobacter sphaeroides bacterial reaction center (bRC). To provide insight into system-bath interactions of the bacteriochlorophyll a (BChl a) special pair, i.e., P870, in the mutated bRC, the optical line shape function for the P870 band is calculated numerically. On the basis of the modeling studies, we demonstrate that (M)L214G mutation leads to a heterogeneous population of bRCs with modified (increased) total electron-phonon coupling strength of the special pair BChl a and larger inhomogeneous broadening. Specifically, we show that after mutation in the (M)L214G bRC a large fraction (∼50%) of the bacteriopheophytin (HA) chromophores shifts red and the 800 nm absorption band broadens, while the remaining fraction of HA cofactors retains nearly the same site energy as HA in the wild-type bRC. Modeling using these two subpopulations allowed for fits of the absorption and nonresonant (transient) HB spectra of the mutant bRC in the charge neutral, oxidized, and charge-separated states using the Frenkel exciton Hamiltonian, providing new insight into the mutant's complex electronic structure. Although the average (M)L214G mutant quantum efficiency of P(+)QA(-) state formation seems to be altered in comparison with the wild-type bRC, the average electron transfer time (measured via resonant transient HB spectra within the P870 band) was not affected. Thus, mutation in the vicinity of the electron acceptor (HA) does not tune the charge separation dynamics. Finally, quenching of the (M)L214G mutant excited states by P(+) is addressed by persistent HB spectra burned within the B band in chemically oxidized samples.
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Affiliation(s)
| | - Olga Rancova
- Department of Theoretical Physics, Vilnius University , 10222 Vilnius, Lithuania
| | | | | | - Rafael G Saer
- Department of Microbiology and Immunology, University of British Columbia , Vancouver, BC V6T 1Z3, Canada
| | - J Thomas Beatty
- Department of Microbiology and Immunology, University of British Columbia , Vancouver, BC V6T 1Z3, Canada
| | - Darius Abramavicius
- Department of Theoretical Physics, Vilnius University , 10222 Vilnius, Lithuania
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Rancova O, Jankowiak R, Kell A, Jassas M, Abramavicius D. Band Structure of the Rhodobacter sphaeroides Photosynthetic Reaction Center from Low-Temperature Absorption and Hole-Burned Spectra. J Phys Chem B 2016; 120:5601-16. [DOI: 10.1021/acs.jpcb.6b02595] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Olga Rancova
- Department
of Theoretical Physics, Vilnius University, Sauletekio al 9-III, 10222 Vilnius, Lithuania
| | | | | | | | - Darius Abramavicius
- Department
of Theoretical Physics, Vilnius University, Sauletekio al 9-III, 10222 Vilnius, Lithuania
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19
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Kell A, Bednarczyk D, Acharya K, Chen J, Noy D, Jankowiak R. New Insight into the Water-Soluble Chlorophyll-Binding Protein fromLepidium virginicum. Photochem Photobiol 2016; 92:428-35. [DOI: 10.1111/php.12581] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/18/2016] [Indexed: 01/20/2023]
Affiliation(s)
- Adam Kell
- Department of Chemistry; Kansas State University; Manhattan Kansas 66506
| | - Dominika Bednarczyk
- Department of Biological Chemistry; Weizmann Institute of Sciences; Rehovot 76100 Israel
| | - Khem Acharya
- Department of Chemistry; Kansas State University; Manhattan Kansas 66506
| | - Jinhai Chen
- Department of Chemistry; Kansas State University; Manhattan Kansas 66506
| | - Dror Noy
- Migal-Galilee Research Institute; Kiryat Shmona 11016 Israel
| | - Ryszard Jankowiak
- Department of Chemistry; Kansas State University; Manhattan Kansas 66506
- Department of Physics; Kansas State University; Manhattan Kansas 66506
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20
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Kell A, Chen J, Jassas M, Tang JKH, Jankowiak R. Alternative Excitonic Structure in the Baseplate (BChl a-CsmA Complex) of the Chlorosome from Chlorobaculum tepidum. J Phys Chem Lett 2015; 6:2702-2707. [PMID: 26266851 DOI: 10.1021/acs.jpclett.5b01074] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In the photosynthetic green sulfur bacterium Chlorobaculum tepidum, the baseplate mediates excitation energy transfer from the light-harvesting chlorosome to the Fenna-Matthews-Olson (FMO) complex and subsequently toward the reaction center (RC). Literature data suggest that the baseplate is a 2D lattice of BChl a-CsmA dimers. However, recently, it has been proposed, using 2D electronic spectroscopy (2DES) at 77 K, that at least four excitonically coupled BChl a are in close contact within the baseplate structure [ Dostál , J. ; et al., J. Phys. Chem. Lett. 2014 , 5 , 1743 ]. This finding is tested via hole burning (HB) spectroscopy (5 K). Our results indicate that the four excitonic states identified by 2DES likely correspond to contamination of the baseplate with the FMO antenna and possibly the RC. In contrast, HB reveals a different excitonic structure of the baseplate chromophores, where excitation is transferred to a localized trap state near 818 nm via exciton hopping, which leads to emission near 826 nm.
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Affiliation(s)
| | | | | | - Joseph Kuo-Hsiang Tang
- ‡Department of Chemistry and Biochemistry, Clark University, Worcester, Massachusetts 01610, United States
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21
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Sun J, Golbeck JH. The Presence of the IsiA-PSI Supercomplex Leads to Enhanced Photosystem I Electron Throughput in Iron-Starved Cells of Synechococcus sp. PCC 7002. J Phys Chem B 2015; 119:13549-59. [DOI: 10.1021/acs.jpcb.5b02176] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Junlei Sun
- Department of Biochemistry and Molecular Biology and ‡Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 United States
| | - John H. Golbeck
- Department of Biochemistry and Molecular Biology and ‡Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 United States
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22
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Chen J, Kell A, Acharya K, Kupitz C, Fromme P, Jankowiak R. Critical assessment of the emission spectra of various photosystem II core complexes. PHOTOSYNTHESIS RESEARCH 2015; 124:253-265. [PMID: 25832780 DOI: 10.1007/s11120-015-0128-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Accepted: 03/23/2015] [Indexed: 06/04/2023]
Abstract
We evaluate low-temperature (low-T) emission spectra of photosystem II core complexes (PSII-cc) previously reported in the literature, which are compared with emission spectra of PSII-cc obtained in this work from spinach and for dissolved PSII crystals from Thermosynechococcus (T.) elongatus. This new spectral dataset is used to interpret data published on membrane PSII (PSII-m) fragments from spinach and Chlamydomonas reinhardtii, as well as PSII-cc from T. vulcanus and intentionally damaged PSII-cc from spinach. This study offers new insight into the assignment of emission spectra reported on PSII-cc from different organisms. Previously reported spectra are also compared with data obtained at different saturation levels of the lowest energy state(s) of spinach and T. elongatus PSII-cc via hole burning in order to provide more insight into emission from bleached and/or photodamaged complexes. We show that typical low-T emission spectra of PSII-cc (with closed RCs), in addition to the 695 nm fluorescence band assigned to the intact CP47 complex (Reppert et al. J Phys Chem B 114:11884-11898, 2010), can be contributed to by several emission bands, depending on sample quality. Possible contributions include (i) a band near 690-691 nm that is largely reversible upon temperature annealing, proving that the band originates from CP47 with a bleached low-energy state near 693 nm (Neupane et al. J Am Chem Soc 132:4214-4229, 2010; Reppert et al. J Phys Chem B 114:11884-11898, 2010); (ii) CP43 emission at 683.3 nm (not at 685 nm, i.e., the F685 band, as reported in the literature) (Dang et al. J Phys Chem B 112:9921-9933, 2008; Reppert et al. J Phys Chem B 112:9934-9947, 2008); (iii) trap emission from destabilized CP47 complexes near 691 nm (FT1) and 685 nm (FT2) (Neupane et al. J Am Chem Soc 132:4214-4229, 2010); and (iv) emission from the RC pigments near 686-687 nm. We suggest that recently reported emission of single PSII-cc complexes from T. elongatus may not represent intact complexes, while those obtained for T. elongatus presented in this work most likely represent intact PSII-cc, since they are nearly indistinguishable from emission spectra obtained for various PSII-m fragments.
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Affiliation(s)
- Jinhai Chen
- Department of Chemistry, Kansas State University, Manhattan, KS, 66506, USA
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23
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Kell A, Acharya K, Blankenship RE, Jankowiak R. On destabilization of the Fenna-Matthews-Olson complex of Chlorobaculum tepidum. PHOTOSYNTHESIS RESEARCH 2014; 120:323-329. [PMID: 24584903 DOI: 10.1007/s11120-014-9990-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 02/17/2014] [Indexed: 06/03/2023]
Abstract
The Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Chlorobaculum tepidum was studied with respect to its stability. We provide a critical assessment of published and recently measured optical spectra. FMO complexes were found to destabilize over time producing spectral shifts, with destabilized samples having significantly higher hole-burning efficiencies; indicating a remodeled protein energy landscape. Observed correlated peak shifts near 825 and 815 nm suggest possible correlated (protein) fluctuations. It is proposed that the value of 35 cm(-1) widely used for reorganization energy (E λ ), which has important implications for the contributions to the coherence rate (Kreisbeck and Kramer 3:2828-2833, 2012), in various modeling studies of two-dimensional electronic spectra is overestimated. We demonstrate that the value of E λ is most likely about 15-22 cm(-1) and suggest that spectra reported in the literature (often measured on different FMO samples) exhibit varied peak positions due to different purification/isolation procedures or destabilization effects.
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Affiliation(s)
- Adam Kell
- Department of Chemistry, Kansas State University, Manhattan, KS, 66506, USA
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24
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Kell A, Feng X, Lin C, Yang Y, Li J, Reus M, Holzwarth AR, Jankowiak R. Charge-transfer character of the low-energy Chl a Q(y) absorption band in aggregated light harvesting complexes II. J Phys Chem B 2014; 118:6086-91. [PMID: 24838007 DOI: 10.1021/jp501735p] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One of the key functions of the major light harvesting complex II (LHCII) of higher plants is to protect Photosystem II from photodamage at excessive light conditions in a process called "non-photochemical quenching" (NPQ). Using hole-burning (HB) spectroscopy, we investigated the nature of the low-energy absorption band in aggregated LHCII complexes - which are highly quenched and have been established as a good in vitro model for NPQ. Nonresonant holes reveal that the lowest energy state (located near 683.3 nm) is red-shifted by ~4 nm and significantly broader (by a factor of 4) as compared to nonaggregated trimeric LHCII. Resonant holes burned in the low-energy wing of the absorption spectrum (685-710 nm) showed a high electron-phonon (el-ph) coupling strength with a Huang-Rhys factor S of 3-4. This finding combined with the very low HB efficiency in the long-wavelength absorption tail is consistent with a dominant charge-transfer (CT) character of the lowest energy transition(s) in aggregated LHCII. The value of S decreases at shorter wavelengths (<685 nm), in agreement with previous studies (J. Pieper et al., J. Phys. Chem. B 1999, 103, 2422-2428), proving that the low-energy excitonic state is strongly mixed with the CT states. Our findings support the mechanistic model in which Chl-Chl CT states formed in aggregated LHCII are intermediates in the efficient excited state quenching process (M. G. Müller et al., Chem. Phys. Chem. 2010, 11, 1289-1296; Y. Miloslavina et al., FEBS Lett. 2008, 582, 3625-3631).
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Affiliation(s)
- Adam Kell
- Department of Chemistry and ‡Department of Physics, Kansas State University , Manhattan, Kansas 66505, United States
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25
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Herascu N, Kell A, Acharya K, Jankowiak R, Blankenship RE, Zazubovich V. Modeling of Various Optical Spectra in the Presence of Slow Excitation Energy Transfer in Dimers and Trimers with Weak Interpigment Coupling: FMO as an Example. J Phys Chem B 2014; 118:2032-40. [DOI: 10.1021/jp410586f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Nicoleta Herascu
- Department
of Physics, Concordia University, Montreal, H4B 1R6 Quebec, Canada
| | | | | | | | | | - Valter Zazubovich
- Department
of Physics, Concordia University, Montreal, H4B 1R6 Quebec, Canada
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26
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Feng X, Pan X, Li M, Pieper J, Chang W, Jankowiak R. Spectroscopic Study of the Light-Harvesting CP29 Antenna Complex of Photosystem II—Part I. J Phys Chem B 2013; 117:6585-92. [DOI: 10.1021/jp4004328] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ximao Feng
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United
States
| | - Xiaowei Pan
- National Laboratory
of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Mei Li
- National Laboratory
of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jörg Pieper
- Institute of Physics, University of Tartu, Tartu, Estonia
| | - Wenrui Chang
- National Laboratory
of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United
States
- Faculty of Applied Physics and Mathematics, Gdańsk University of Technology, Gdańsk,
Poland
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27
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Neupane B, Jaschke P, Saer R, Beatty JT, Reppert M, Jankowiak R. Electron Transfer in Rhodobacter sphaeroides Reaction Centers Containing Zn-Bacteriochlorophylls: A Hole-Burning Study. J Phys Chem B 2012; 116:3457-66. [DOI: 10.1021/jp300304r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Paul Jaschke
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Rafael Saer
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - J. Thomas Beatty
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Mike Reppert
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
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