1
|
Šímová I, Kuznetsova V, Gardiner AT, Šebelík V, Koblížek M, Fuciman M, Polívka T. Carotenoid responds to excess energy dissipation in the LH2 complex from Rhodoblastus acidophilus. PHOTOSYNTHESIS RESEARCH 2022; 154:75-87. [PMID: 36066816 DOI: 10.1007/s11120-022-00952-5] [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: 06/22/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
The functions of both (bacterio) chlorophylls and carotenoids in light-harvesting complexes have been extensively studied during the past decade, yet, the involvement of BChl a high-energy Soret band in the cascade of light-harvesting processes still remains a relatively unexplored topic. Here, we present transient absorption data recorded after excitation of the Soret band in the LH2 complex from Rhodoblastus acidophilus. Comparison of obtained data to those recorded after excitation of rhodopin glucoside and B800 BChl a suggests that no Soret-to-Car energy transfer pathway is active in LH2 complex. Furthermore, a spectrally rich pattern observed in the spectral region of rhodopin glucoside ground state bleaching (420-550 nm) has been assigned to an electrochromic shift. The results of global fitting analysis demonstrate two more features. A 6 ps component obtained exclusively after excitation of the Soret band has been assigned to the response of rhodopin glucoside to excess energy dissipation in LH2. Another time component, ~ 450 ps, appearing independently of the excitation wavelength was assigned to BChl a-to-Car triplet-triplet transfer. Presented data demonstrate several new features of LH2 complex and its behavior following the excitation of the Soret band.
Collapse
Affiliation(s)
- Ivana Šímová
- Department of Physics, Faculty of Science, University of South Bohemia, Branišovská, 1760, 370 05, Ceske Budejovice, Czech Republic
| | - Valentyna Kuznetsova
- Department of Physics, Faculty of Science, University of South Bohemia, Branišovská, 1760, 370 05, Ceske Budejovice, Czech Republic
| | - Alastair T Gardiner
- Laboratory of Anoxygenic Phototrophs, Institute of Microbiology, Czech Academy of Sciences, 379 81, Třeboň, Czech Republic
| | - Václav Šebelík
- Department of Physics, Faculty of Science, University of South Bohemia, Branišovská, 1760, 370 05, Ceske Budejovice, Czech Republic
- Dynamical Spectroscopy, Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748, Garching b. Munich, Germany
| | - Michal Koblížek
- Laboratory of Anoxygenic Phototrophs, Institute of Microbiology, Czech Academy of Sciences, 379 81, Třeboň, Czech Republic
| | - Marcel Fuciman
- Department of Physics, Faculty of Science, University of South Bohemia, Branišovská, 1760, 370 05, Ceske Budejovice, Czech Republic
| | - Tomáš Polívka
- Department of Physics, Faculty of Science, University of South Bohemia, Branišovská, 1760, 370 05, Ceske Budejovice, Czech Republic.
| |
Collapse
|
2
|
van den Berg TE, Croce R. The Loroxanthin Cycle: A New Type of Xanthophyll Cycle in Green Algae (Chlorophyta). FRONTIERS IN PLANT SCIENCE 2022; 13:797294. [PMID: 35251077 PMCID: PMC8891138 DOI: 10.3389/fpls.2022.797294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Xanthophyll cycles (XC) have proven to be major contributors to photoacclimation for many organisms. This work describes a light-driven XC operating in the chlorophyte Chlamydomonas reinhardtii and involving the xanthophylls Lutein (L) and Loroxanthin (Lo). Pigments were quantified during a switch from high to low light (LL) and at different time points from cells grown in Day/Night cycle. Trimeric LHCII was purified from cells acclimated to high or LL and their pigment content and spectroscopic properties were characterized. The Lo/(L + Lo) ratio in the cells varies by a factor of 10 between cells grown in low or high light (HL) leading to a change in the Lo/(L + Lo) ratio in trimeric LHCII from .5 in low light to .07 in HL. Trimeric LhcbMs binding Loroxanthin have 5 ± 1% higher excitation energy (EE) transfer (EET) from carotenoid to Chlorophyll as well as higher thermo- and photostability than trimeric LhcbMs that only bind Lutein. The Loroxanthin cycle operates on long time scales (hours to days) and likely evolved as a shade adaptation. It has many similarities with the Lutein-epoxide - Lutein cycle (LLx) of plants.
Collapse
|
3
|
Nupur, Kuzma M, Hájek J, Hrouzek P, Gardiner AT, Lukeš M, Moos M, Šimek P, Koblížek M. Structure elucidation of the novel carotenoid gemmatoxanthin from the photosynthetic complex of Gemmatimonas phototrophica AP64. Sci Rep 2021; 11:15964. [PMID: 34354109 PMCID: PMC8342508 DOI: 10.1038/s41598-021-95254-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/20/2021] [Indexed: 11/09/2022] Open
Abstract
Gemmatimonas phototrophica AP64 is the first phototrophic representative of the bacterial phylum Gemmatimonadetes. The cells contain photosynthetic complexes with bacteriochlorophyll a as the main light-harvesting pigment and an unknown carotenoid with a single broad absorption band at 490 nm in methanol. The carotenoid was extracted from isolated photosynthetic complexes, and purified by liquid chromatography. A combination of nuclear magnetic resonance (1H NMR, COSY, 1H-13C HSQC, 1H-13C HMBC, J-resolved, and ROESY), high-resolution mass spectroscopy, Fourier-transformed infra-red, and Raman spectroscopy was used to determine its chemical structure. The novel linear carotenoid, that we have named gemmatoxanthin, contains 11 conjugated double bonds and is further substituted by methoxy, carboxyl and aldehyde groups. Its IUPAC-IUBMB semi-systematic name is 1'-Methoxy-19'-oxo-3',4'-didehydro-7,8,1',2'-tetrahydro- Ψ, Ψ carotene-16-oic acid. To our best knowledge, the presence of the carboxyl, methoxy and aldehyde groups on a linear C40 carotenoid backbone is reported here for the first time.
Collapse
Affiliation(s)
- Nupur
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 379 81, Třeboň, Czech Republic
| | - Marek Kuzma
- Laboratory of Molecular Structure Characterization, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, Czech Republic
| | - Jan Hájek
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 379 81, Třeboň, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 1760, České Budějovice, Czech Republic
| | - Pavel Hrouzek
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 379 81, Třeboň, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 1760, České Budějovice, Czech Republic
| | - Alastair T Gardiner
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 379 81, Třeboň, Czech Republic
| | - Martin Lukeš
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 379 81, Třeboň, Czech Republic
| | - Martin Moos
- Biology Centre of the Czech Academy of Sciences, Branišovská 1160/31, 370 05, České Budějovice, Czech Republic
| | - Petr Šimek
- Biology Centre of the Czech Academy of Sciences, Branišovská 1160/31, 370 05, České Budějovice, Czech Republic
| | - Michal Koblížek
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, 379 81, Třeboň, Czech Republic.
| |
Collapse
|
4
|
Razjivin A, Götze J, Lukashev E, Kozlovsky V, Ashikhmin A, Makhneva Z, Moskalenko A, Lokstein H, Paschenko V. Lack of Excitation Energy Transfer from the Bacteriochlorophyll Soret Band to Carotenoids in Photosynthetic Complexes of Purple Bacteria. J Phys Chem B 2021; 125:3538-3545. [PMID: 33818091 DOI: 10.1021/acs.jpcb.1c00719] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The excitation energy transfer (EET) from the bacteriochlorophyll (BChl) Soret band to the second excited state(s) (S2) of carotenoids in pigment-protein complexes of purple bacteria was investigated. The efficiency of EET was determined, based on fluorescence excitation and absorption spectra of chromatophores, peripheral light-harvesting complexes (LH2), core complexes (LH1-RC), and pigments in solution. Carotenoid-containing and carotenoid-less samples were compared: LH1-RC and LH2 from Allochromatium minutissimum, Ectothiorhodospira haloalkaliphila, and chromatophores from Rhodobacter sphaeroides and Rhodospirillum rubrum wild type and carotenoid-free strains R-26 and G9. BChl-to-carotenoid EET was absent, or its efficiency was less than the accuracy of the measurements of ∼5%. Quantum chemical calculations support the experimental results: The transition dipole moments of spatially close carotenoid/BChl pairs were found to be nearly orthogonal. The structural arrangements suggest that Soret EET may be lacking for the studied systems, however, EET from carotenoids to Qx appears to be possible.
Collapse
Affiliation(s)
- Andrei Razjivin
- Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Jan Götze
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Evgeny Lukashev
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Vladimir Kozlovsky
- Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Aleksandr Ashikhmin
- Institute of Basic Biological Problems of Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of Russian Academy of Sciences", 142290, Pushchino, Russia
| | - Zoya Makhneva
- Institute of Basic Biological Problems of Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of Russian Academy of Sciences", 142290, Pushchino, Russia
| | - Andrey Moskalenko
- Institute of Basic Biological Problems of Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of Russian Academy of Sciences", 142290, Pushchino, Russia
| | - Heiko Lokstein
- Department of Chemical Physics and Optics, Charles University, Ke Karlovu 3, 121 16 Prague, Czech Republic
| | - Vladimir Paschenko
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| |
Collapse
|
5
|
Claridge K, Padula D, Troisi A. On the arrangement of chromophores in light harvesting complexes: chance versus design. Faraday Discuss 2019; 221:133-149. [PMID: 31544201 DOI: 10.1039/c9fd00045c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We used a homogeneous computational approach to derive the excitonic Hamiltonian for five light harvesting complexes containing only one type of chromophore and compare them in terms of statistical descriptors. We then studied the approximate exciton dynamics for the five complexes introducing a measure, the (averaged and time-dependent) inverse participation ratio, that enables the comparison between very diverse complexes on the same ground. We find that the global dynamics are very similar across the set of systems despite the variety of geometric structures of the complexes. In particular, the dynamics of four out of five light harvesting complexes are barely distinguishable with a small variation from the norm seen only for the Fenna-Matthews-Olson complex. We use the information from the realistic Hamiltonians to build a reduced model system that shows how the global dynamics are ultimately dominated by a single parameter, the degree of localization of the excitonic Hamiltonian eigenstates. Considering the physically plausible range of system parameters, the reduced model explains why the dynamics are so similar across most light harvesting complexes containing a single type of chromophore regardless of the detailed pattern of the inter-chromophore excitonic coupling.
Collapse
Affiliation(s)
- Kirsten Claridge
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK.
| | | | | |
Collapse
|
6
|
Cardoso Ramos F, Nottoli M, Cupellini L, Mennucci B. The molecular mechanisms of light adaption in light-harvesting complexes of purple bacteria revealed by a multiscale modeling. Chem Sci 2019; 10:9650-9662. [PMID: 32055335 PMCID: PMC6988754 DOI: 10.1039/c9sc02886b] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/23/2019] [Indexed: 12/27/2022] Open
Abstract
The light-harvesting in photosynthetic purple bacteria can be tuned in response to the light conditions during cell growth. One of the used strategies is to change the energy of the excitons in the major fight-harvesting complex, commonly known as LH2. In the present study we report the first systematic investigation of the microscopic origin of the exciton tuning using three complexes, namely the common (high-light) and the low-light forms of LH2 from Rps. acidophila plus a third complex analogous to the PucD complex from Rps. palustris. The study is based on the combination of classical molecular dynamics of each complex in a lipid membrane and excitonic calculations based on a multiscale quantum mechanics/molecular mechanics approach including a polarizable embedding. From the comparative analysis, it comes out that the mechanisms that govern the adaptation of the complex to different light conditions use the different H-bonding environment around the bacteriochlorophyll pigments to dynamically control both internal and inter-pigment degrees of freedom. While the former have a large effect on the site energies, the latter significantly change the electronic couplings, but only the combination of the two effects can fully reproduce the tuning of the final excitons and explain the observed spectroscopic differences.
Collapse
Affiliation(s)
- Felipe Cardoso Ramos
- Dipartimento di Chimica e Chimica Industriale , Università di Pisa , Via G. Moruzzi 13 , 56124 Pisa , Italy .
| | - Michele Nottoli
- Dipartimento di Chimica e Chimica Industriale , Università di Pisa , Via G. Moruzzi 13 , 56124 Pisa , Italy .
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale , Università di Pisa , Via G. Moruzzi 13 , 56124 Pisa , Italy .
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale , Università di Pisa , Via G. Moruzzi 13 , 56124 Pisa , Italy .
| |
Collapse
|
7
|
Wei T, Balevičius V, Polívka T, Ruban AV, Duffy CDP. How carotenoid distortions may determine optical properties: lessons from the Orange Carotenoid Protein. Phys Chem Chem Phys 2019; 21:23187-23197. [PMID: 31612872 DOI: 10.1039/c9cp03574e] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carotenoids in photosynthetic proteins carry out the dual function of harvesting light and defending against photo-damage by quenching excess energy. The latter involves the low-lying, dark, excited state labelled S1. Here "dark" means optically-forbidden, a property that is often attributed to molecular symmetry, which leads to speculation that its optical properties may be strongly-perturbed by structural distortions. This has been both explicitly and implicitly proposed as an important feature of photo-protective energy quenching. Here we present a theoretical analysis of the relationship between structural distortions and S1 optical properties. We outline how S1 is dark not because of overall geometric symmetry but because of a topological symmetry related to bond length alternation in the conjugated backbone. Taking the carotenoid echinenone as an example and using a combination of molecular dynamics, quantum chemistry, and the theory of spectral lineshapes, we show that distortions that break this symmetry are extremely stiff. They are therefore absent in solution and only marginally present in even a very highly-distorted protein binding pocket such as in the Orange Carotenoid Protein (OCP). S1 remains resolutely optically-forbidden despite any breaking of bulk molecular symmetry by the protein environment. However, rotations of partially conjugated end-rings can result in fine tuning of the S1 transition density which may exert some influence on interactions with neighbouring chromophores.
Collapse
Affiliation(s)
- Tiejun Wei
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
| | | | | | | | | |
Collapse
|
8
|
Wurtzel ET. Changing Form and Function through Carotenoids and Synthetic Biology. PLANT PHYSIOLOGY 2019; 179:830-843. [PMID: 30361256 PMCID: PMC6393808 DOI: 10.1104/pp.18.01122] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/06/2018] [Indexed: 05/06/2023]
Abstract
The diverse structures and multifaceted roles of carotenoids make these colorful pigments attractive targets for synthetic biology.
Collapse
Affiliation(s)
- Eleanore T Wurtzel
- Department of Biological Sciences, Lehman College, The City University of New York, Bronx, New York 10468
- The Graduate School and University Center-CUNY, New York, New York 10016-4309
| |
Collapse
|
9
|
Nottoli M, Jurinovich S, Cupellini L, Gardiner AT, Cogdell R, Mennucci B. The role of charge-transfer states in the spectral tuning of antenna complexes of purple bacteria. PHOTOSYNTHESIS RESEARCH 2018; 137:215-226. [PMID: 29502240 DOI: 10.1007/s11120-018-0492-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/23/2018] [Indexed: 05/21/2023]
Abstract
The LH2 antenna complexes of purple bacteria occur, depending on light conditions, in various different spectroscopic forms, with a similar structure but different absorption spectra. The differences are related to point changes in the primary amino acid sequence, but the molecular-level relationship between these changes and the resulting spectrum is still not well understood. We undertook a systematic quantum chemical analysis of all the main factors that contribute to the exciton structure, looking at how the environment modulates site energies and couplings in the B800-850 and B800-820 spectroscopic forms of LH2. A multiscale approach combining quantum chemistry and an atomistic classical embedding has been used where mutual polarization effects between the two parts are taken into account. We find that the loss of hydrogen bonds following amino acid changes can only explain a part of the observed blue-shift in the B850 band. The coupling of excitonic states to charge-transfer states, which is different in the two forms, contributes with a similar amount to the overall blue-shift.
Collapse
Affiliation(s)
- Michele Nottoli
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, I-56124, Pisa, Italy
| | - Sandro Jurinovich
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, I-56124, Pisa, Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, I-56124, Pisa, Italy
| | - Alastair T Gardiner
- Glasgow Biomedical Research Centre, Institute of Molecular Cell and Systems Biology, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
| | - Richard Cogdell
- Glasgow Biomedical Research Centre, Institute of Molecular Cell and Systems Biology, University of Glasgow, 126 University Place, Glasgow, G12 8TA, Scotland, UK
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, I-56124, Pisa, Italy.
| |
Collapse
|
10
|
Razjivin AP, Lukashev EP, Kompanets VO, Kozlovsky VS, Ashikhmin AA, Chekalin SV, Moskalenko AA, Paschenko VZ. Excitation energy transfer from the bacteriochlorophyll Soret band to carotenoids in the LH2 light-harvesting complex from Ectothiorhodospira haloalkaliphila is negligible. PHOTOSYNTHESIS RESEARCH 2017; 133:289-295. [PMID: 28205063 DOI: 10.1007/s11120-017-0341-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/18/2017] [Indexed: 06/06/2023]
Abstract
Pathways of intramolecular conversion and intermolecular electronic excitation energy transfer (EET) in the photosynthetic apparatus of purple bacteria remain subject to debate. Here we experimentally tested the possibility of EET from the bacteriochlorophyll (BChl) Soret band to the singlet S2 level of carotenoids using femtosecond pump-probe measurements and steady-state fluorescence excitation and absorption measurements in the near-ultraviolet and visible spectral ranges. The efficiency of EET from the Soret band of BChl to S2 of the carotenoids in light-harvesting complex LH2 from the purple bacterium Ectothiorhodospira haloalkaliphila appeared not to exceed a few percent.
Collapse
Affiliation(s)
- A P Razjivin
- Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119991.
| | - E P Lukashev
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia, 119991
| | - V O Kompanets
- Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow, Russia, 142190
| | - V S Kozlovsky
- Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119991
| | - A A Ashikhmin
- Institute of Fundamental Problems of Biology, Russian Academy of Sciences, Pushchino, Moscow Region, Russia, 142290
| | - S V Chekalin
- Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow, Russia, 142190
| | - A A Moskalenko
- Institute of Fundamental Problems of Biology, Russian Academy of Sciences, Pushchino, Moscow Region, Russia, 142290
| | - V Z Paschenko
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia, 119991
| |
Collapse
|
11
|
A new energy transfer channel from carotenoids to chlorophylls in purple bacteria. Nat Commun 2017; 8:71. [PMID: 28694423 PMCID: PMC5504074 DOI: 10.1038/s41467-017-00120-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 06/01/2017] [Indexed: 11/17/2022] Open
Abstract
It is unclear whether there is an intermediate dark state between the S2 and S1 states of carotenoids. Previous two-dimensional electronic spectroscopy measurements support its existence and its involvement in the energy transfer from carotenoids to chlorophylls, but there is still considerable debate on the origin of this dark state and how it regulates the energy transfer process. Here we use ab initio calculations on excited-state dynamics and simulated two-dimensional electronic spectrum of carotenoids from purple bacteria to provide evidence supporting that the dark state may be assigned to a new Ag+ state. Our calculations also indicate that groups on the conjugation backbone of carotenoids may substantially affect the excited-state levels and the energy transfer process. These results contribute to a better understanding of carotenoid excited states. Carotenoids harvest energy from light and transfer it to chlorophylls during photosynthesis. Here, Feng et al. perform ab initio calculations on excited-state dynamics and simulated 2D electronic spectrum of carotenoids, supporting the existence of a new excited state in carotenoids.
Collapse
|
12
|
Magdaong NCM, Niedzwiedzki DM, Goodson C, Blankenship RE. Carotenoid-to-Bacteriochlorophyll Energy Transfer in the LH1–RC Core Complex of a Bacteriochlorophyll b Containing Purple Photosynthetic Bacterium Blastochloris viridis. J Phys Chem B 2016; 120:5159-71. [DOI: 10.1021/acs.jpcb.6b04307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nikki Cecil M. Magdaong
- Department
of Biology, Washington University in Saint Louis, One Brookings
Drive, St. Louis, Missouri 63130 United States
- Department of Chemistry, Washington University in Saint Louis, One Brookings Drive, St.
Louis, Missouri 63130 United States
- Photosynthetic
Antenna Research Center, 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
| | - Carrie Goodson
- Department
of Biology, Washington University in Saint Louis, One Brookings
Drive, St. Louis, Missouri 63130 United States
| | - Robert E. Blankenship
- Department
of Biology, Washington University in Saint Louis, One Brookings
Drive, St. Louis, Missouri 63130 United States
- Department of Chemistry, Washington University in Saint Louis, One Brookings Drive, St.
Louis, Missouri 63130 United States
- Photosynthetic
Antenna Research Center, Washington University in Saint Louis, One Brookings
Drive, St. Louis, Missouri 63130 United States
| |
Collapse
|
13
|
Makhneva ZK, Ashikhmin AA, Bolshakov MA, Moskalenko AA. 3-Acetyl-chlorophyll formation in light-harvesting complexes of purple bacteria by chemical oxidation. BIOCHEMISTRY (MOSCOW) 2016; 81:176-86. [DOI: 10.1134/s0006297916020115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
14
|
Magdaong NM, LaFountain AM, Hacking K, Niedzwiedzki DM, Gibson GN, Cogdell RJ, Frank HA. Spectral heterogeneity and carotenoid-to-bacteriochlorophyll energy transfer in LH2 light-harvesting complexes from Allochromatium vinosum. PHOTOSYNTHESIS RESEARCH 2016; 127:171-187. [PMID: 26048106 DOI: 10.1007/s11120-015-0165-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 06/01/2015] [Indexed: 06/04/2023]
Abstract
Photosynthetic organisms produce a vast array of spectral forms of antenna pigment-protein complexes to harvest solar energy and also to adapt to growth under the variable environmental conditions of light intensity, temperature, and nutrient availability. This behavior is exemplified by Allochromatium (Alc.) vinosum, a photosynthetic purple sulfur bacterium that produces different types of LH2 light-harvesting complexes in response to variations in growth conditions. In the present work, three different spectral forms of LH2 from Alc. vinosum, B800-820, B800-840, and B800-850, were isolated, purified, and examined using steady-state absorption and fluorescence spectroscopy, and ultrafast time-resolved absorption spectroscopy. The pigment composition of the LH2 complexes was analyzed by high-performance liquid chromatography, and all were found to contain five carotenoids: lycopene, anhydrorhodovibrin, spirilloxanthin, rhodopin, and rhodovibrin. Spectral reconstructions of the absorption and fluorescence excitation spectra based on the pigment composition revealed significantly more spectral heterogeneity in these systems compared to LH2 complexes isolated from other species of purple bacteria. The data also revealed the individual carotenoid-to-bacteriochlorophyll energy transfer efficiencies which were correlated with the kinetic data from the ultrafast transient absorption spectroscopic experiments. This series of LH2 complexes allows a systematic exploration of the factors that determine the spectral properties of the bound pigments and control the rate and efficiency of carotenoid-to-bacteriochlorophyll energy transfer.
Collapse
Affiliation(s)
- Nikki M Magdaong
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, CT, 06269-3060, USA
| | - Amy M LaFountain
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, CT, 06269-3060, USA
| | - Kirsty Hacking
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, Scotland, UK
| | - Dariusz M Niedzwiedzki
- Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, MO, USA
| | - George N Gibson
- Department of Physics, University of Connecticut, 2152 Hillside Road, Storrs, CT, 06269-3046, USA
| | - Richard J Cogdell
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, Scotland, UK
| | - Harry A Frank
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, CT, 06269-3060, USA.
| |
Collapse
|