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Knox PP, Lukashev EP, Korvatovsky BN, Mamedov MD, Strakhovskaya MG, Gvozdev DA, Paschenko VZ, Rubin AB. The influence of cationic antiseptics on the processes of light energy conversion in various photosynthetic pigment-protein complexes. PHOTOSYNTHESIS RESEARCH 2024; 161:5-19. [PMID: 38466457 DOI: 10.1007/s11120-024-01082-w] [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: 12/20/2023] [Accepted: 01/29/2024] [Indexed: 03/13/2024]
Abstract
The widespread use of disinfectants and antiseptics, and consequently their release into the environment, determines the relevance of studying their potential impact on the main producers of organic matter on the planet-photosynthetic organisms. The review examines the effects of some biguanides and quaternary ammonium compounds, octenidine, miramistin, chlorhexidine, and picloxidine, on the functioning of the photosynthetic apparatus of various organisms (Strakhovskaya et al. in Photosynth Res 147:197-209, 2021; Knox et al. in Photosynth Res 153:103, 2022; Paschenko et al. in Photosynth Res 155:93-105, 2023a, Photosynth Res 2023b). A common feature of these antiseptics is the combination of hydrophobic and hydrophilic regions in the molecules, the latter carrying a positive charge(s). The comparison of the results obtained with intact bacterial membrane vesicles (chromatophores) and purified pigment-protein complexes (photosystem II and I) of oxygenic organisms allows us to draw conclusions about the mechanisms of the cationic antiseptic action on the functional properties of the components of the photosynthetic apparatus.
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Affiliation(s)
- Peter P Knox
- Biophysical Department, Faculty of Biology, Moscow State University, Leninskye Gory 1, Build. 24, Moscow, Russia, 119234
| | - Eugene P Lukashev
- Biophysical Department, Faculty of Biology, Moscow State University, Leninskye Gory 1, Build. 24, Moscow, Russia, 119234
| | - Boris N Korvatovsky
- Biophysical Department, Faculty of Biology, Moscow State University, Leninskye Gory 1, Build. 24, Moscow, Russia, 119234
| | - Mahir D Mamedov
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskye Gory 1, Build. 40, Moscow, Russia, 119992
| | - Marina G Strakhovskaya
- Synthetic Biology Department, Faculty of Biology, Moscow State University, Leninskye Gory 1, Build. 12, Moscow, Russia, 119234
| | - Daniil A Gvozdev
- Biophysical Department, Faculty of Biology, Moscow State University, Leninskye Gory 1, Build. 24, Moscow, Russia, 119234.
| | - Vladimir Z Paschenko
- Biophysical Department, Faculty of Biology, Moscow State University, Leninskye Gory 1, Build. 24, Moscow, Russia, 119234
| | - Andrew B Rubin
- Biophysical Department, Faculty of Biology, Moscow State University, Leninskye Gory 1, Build. 24, Moscow, Russia, 119234
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2
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Huang X, Vasilev C, Swainsbury D, Hunter C. Excitation energy transfer in proteoliposomes reconstituted with LH2 and RC-LH1 complexes from Rhodobacter sphaeroides. Biosci Rep 2024; 44:BSR20231302. [PMID: 38227291 PMCID: PMC10876425 DOI: 10.1042/bsr20231302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/30/2023] [Accepted: 01/16/2024] [Indexed: 01/17/2024] Open
Abstract
Light-harvesting 2 (LH2) and reaction-centre light-harvesting 1 (RC-LH1) complexes purified from the photosynthetic bacterium Rhodobacter (Rba.) sphaeroides were reconstituted into proteoliposomes either separately, or together at three different LH2:RC-LH1 ratios, for excitation energy transfer studies. Atomic force microscopy (AFM) was used to investigate the distribution and association of the complexes within the proteoliposome membranes. Absorption and fluorescence emission spectra were similar for LH2 complexes in detergent and liposomes, indicating that reconstitution retains the structural and optical properties of the LH2 complexes. Analysis of fluorescence emission shows that when LH2 forms an extensive series of contacts with other such complexes, fluorescence is quenched by 52.6 ± 1.4%. In mixed proteoliposomes, specific excitation of carotenoids in LH2 donor complexes resulted in emission of fluorescence from acceptor RC-LH1 complexes engineered to assemble with no carotenoids. Extents of energy transfer were measured by fluorescence lifetime microscopy; the 0.72 ± 0.08 ns lifetime in LH2-only membranes decreases to 0.43 ± 0.04 ns with a ratio of 2:1 LH2 to RC-LH1, and to 0.35 ± 0.05 ns for a 1:1 ratio, corresponding to energy transfer efficiencies of 40 ± 14% and 51 ± 18%, respectively. No further improvement is seen with a 0.5:1 LH2 to RC-LH1 ratio. Thus, LH2 and RC-LH1 complexes perform their light harvesting and energy transfer roles when reconstituted into proteoliposomes, providing a way to integrate native, non-native, engineered and de novo designed light-harvesting complexes into functional photosynthetic systems.
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Affiliation(s)
- Xia Huang
- Department of Biological Sciences, Xi’an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123, China
- Jinan Guoke Medical Technology Development Co., Ltd, Jinan, Shandong 250101, China
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - Cvetelin Vasilev
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - David J.K. Swainsbury
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
| | - C. Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
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3
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Dewa T, Kimoto K, Kasagi G, Harada H, Sumino A, Kondo M. Functional Coupling of Biohybrid Photosynthetic Antennae and Reaction Center Complexes: Quantitative Comparison with Native Antennae. J Phys Chem B 2023; 127:10315-10325. [PMID: 38015096 DOI: 10.1021/acs.jpcb.3c04922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Light-harvesting (LH) complexes in photosynthetic organisms absorb photons within limited wavelength ranges over a broad solar spectrum. Extension of the LH wavelength has been realized by attaching artificial fluorophores to LH complexes (biohybrid LH complexes) for complementing the limited-wavelength regions. However, how efficiently such fluorophores in biohybrid LH complexes function to drive the photocatalytic reaction center (RC) has not been quantitatively evaluated, specifically in comparison with native LH antenna complexes. In this study, we prepared various biohybrid LH1-RC complexes (from Rhodopseudomonas palustris), to quantitatively evaluate the LH activity of the attached external chromophores through a photocurrent generation reaction by LH1-RC on an electrode. For a direct comparison of the LH activity among the LH chromophores that were examined, we introduced the k1 term, which represents the extent of the functional coupling of LH and the photochemical reactions in the RC. We determined that the hydrophobic fluorophore ATTO647N attached to LH1 possesses the highest LH activity among the examined hydrophilic fluorophores such as Alexa647, and its activity is comparable to that of native LH1(-RC). The LH activity of LH2 (from Rhodoblastus acidophilus strain 10050) and its biohybrid LH2s were examined for the comprehensive assessment of their LH activity.
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Affiliation(s)
- Takehisa Dewa
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Komei Kimoto
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Genki Kasagi
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Hiromi Harada
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Ayumi Sumino
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Masaharu Kondo
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
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4
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Knox PP, Lukashev EP, Korvatovskiy BN, Strakhovskaya MG, Makhneva ZK, Bol'shakov MA, Paschenko VZ. Disproportionate effect of cationic antiseptics on the quantum yield and fluorescence lifetime of bacteriochlorophyll molecules in the LH1-RC complex of R. rubrum chromatophores. PHOTOSYNTHESIS RESEARCH 2022; 153:103-112. [PMID: 35277801 DOI: 10.1007/s11120-022-00909-8] [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: 01/08/2022] [Accepted: 02/26/2022] [Indexed: 06/14/2023]
Abstract
Photosynthetic membrane complexes of purple bacteria are convenient and informative macromolecular systems for studying the mechanisms of action of various physicochemical factors on the functioning of catalytic proteins both in an isolated state and as part of functional membranes. In this work, we studied the effect of cationic antiseptics (chlorhexidine, picloxydine, miramistin, and octenidine) on the fluorescence intensity and the efficiency of energy transfer from the light-harvesting LH1 complex to the reaction center (RC) of Rhodospirillum rubrum chromatophores. The effect of antiseptics on the fluorescence intensity and the energy transfer increased in the following order: chlorhexidine, picloxydine, miramistin, octenidine. The most pronounced changes in the intensity and lifetime of fluorescence were observed with the addition of miramistin and octenidine. At the same concentration of antiseptics, the increase in fluorescence intensity was 2-3 times higher than the increase in its lifetime. It is concluded that the addition of antiseptics decreases the efficiency of the energy migration LH1 → RC and increases the fluorescence rate constant kfl. We associate the latter with a change in the polarization of the microenvironment of bacteriochlorophyll molecules upon the addition of charged antiseptic molecules. A possible mechanism of antiseptic action on R. rubrum chromatophores is considered. This work is a continuation of the study of the effect of antiseptics on the energy transfer and fluorescence intensity in chromatophores of purple bacteria published earlier in Photosynthesis Research (Strakhovskaya et al. in Photosyn Res 147:197-209, 2021).
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Affiliation(s)
- Peter P Knox
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119234
| | - Eugene P Lukashev
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119234
| | - Boris N Korvatovskiy
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119234
| | - Marina G Strakhovskaya
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119234.
| | - Zoja K Makhneva
- Federal Research Center "Pushchino Scientific Center for Biological Research of Russian Academy of Sciences", Pushchino, Russian Federation, 142290
| | - Maxim A Bol'shakov
- Federal Research Center "Pushchino Scientific Center for Biological Research of Russian Academy of Sciences", Pushchino, Russian Federation, 142290
| | - Vladimir Z Paschenko
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation, 119234
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5
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Cryo-EM structure of the Rhodospirillum rubrum RC-LH1 complex at 2.5 Å. Biochem J 2021; 478:3253-3263. [PMID: 34402504 PMCID: PMC8454704 DOI: 10.1042/bcj20210511] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/12/2021] [Accepted: 08/17/2021] [Indexed: 12/03/2022]
Abstract
The reaction centre light-harvesting 1 (RC–LH1) complex is the core functional component of bacterial photosynthesis. We determined the cryo-electron microscopy (cryo-EM) structure of the RC–LH1 complex from Rhodospirillum rubrum at 2.5 Å resolution, which reveals a unique monomeric bacteriochlorophyll with a phospholipid ligand in the gap between the RC and LH1 complexes. The LH1 complex comprises a circular array of 16 αβ-polypeptide subunits that completely surrounds the RC, with a preferential binding site for a quinone, designated QP, on the inner face of the encircling LH1 complex. Quinols, initially generated at the RC QB site, are proposed to transiently occupy the QP site prior to traversing the LH1 barrier and diffusing to the cytochrome bc1 complex. Thus, the QP site, which is analogous to other such sites in recent cryo-EM structures of RC–LH1 complexes, likely reflects a general mechanism for exporting quinols from the RC–LH1 complex.
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Tani K, Kanno R, Ji XC, Hall M, Yu LJ, Kimura Y, Madigan MT, Mizoguchi A, Humbel BM, Wang-Otomo ZY. Cryo-EM Structure of the Photosynthetic LH1-RC Complex from Rhodospirillum rubrum. Biochemistry 2021; 60:2483-2491. [PMID: 34323477 DOI: 10.1021/acs.biochem.1c00360] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rhodospirillum (Rsp.) rubrum is one of the most widely used model organisms in bacterial photosynthesis. This purple phototroph is characterized by the presence of both rhodoquinone (RQ) and ubiquinone as electron carriers and bacteriochlorophyll (BChl) a esterified at the propionic acid side chain by geranylgeraniol (BChl aG) instead of phytol. Despite intensive efforts, the structure of the light-harvesting-reaction center (LH1-RC) core complex from Rsp. rubrum remains at low resolutions. Using cryo-EM, here we present a robust new view of the Rsp. rubrum LH1-RC at 2.76 Å resolution. The LH1 complex forms a closed, slightly elliptical ring structure with 16 αβ-polypeptides surrounding the RC. Our biochemical analysis detected RQ molecules in the purified LH1-RC, and the cryo-EM density map specifically positions RQ at the QA site in the RC. The geranylgeraniol side chains of BChl aG coordinated by LH1 β-polypeptides exhibit a highly homologous tail-up conformation that allows for interactions with the bacteriochlorin rings of nearby LH1 α-associated BChls aG. The structure also revealed key protein-protein interactions in both N- and C-terminal regions of the LH1 αβ-polypeptides, mainly within a face-to-face structural subunit. Our high-resolution Rsp. rubrum LH1-RC structure provides new insight for evaluating past experimental and computational results obtained with this old organism over many decades and lays the foundation for more detailed exploration of light-energy conversion, quinone transport, and structure-function relationships in this pigment-protein complex.
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Affiliation(s)
- Kazutoshi Tani
- Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan
| | - Ryo Kanno
- Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Xuan-Cheng Ji
- Faculty of Science, Ibaraki University, Mito, Ibaraki 310-8512, Japan
| | - Malgorzata Hall
- Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Long-Jiang Yu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yukihiro Kimura
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe, Hyogo 657-8501, Japan
| | - Michael T Madigan
- School of Biological Sciences, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Akira Mizoguchi
- Graduate School of Medicine, Mie University, Tsu, Mie 514-8507, Japan
| | - Bruno M Humbel
- Imaging Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1, Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
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7
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Quinone transport in the closed light-harvesting 1 reaction center complex from the thermophilic purple bacterium Thermochromatium tepidum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148307. [PMID: 32926863 DOI: 10.1016/j.bbabio.2020.148307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 11/22/2022]
Abstract
Redox-active quinones play essential roles in efficient light energy conversion in type-II reaction centers of purple phototrophic bacteria. In the light-harvesting 1 reaction center (LH1-RC) complex of purple bacteria, QB is converted to QBH2 upon light-induced reduction and QBH2 is transported to the quinone pool in the membrane through the LH1 ring. In the purple bacterium Rhodobacter sphaeroides, the C-shaped LH1 ring contains a gap for quinone transport. In contrast, the thermophilic purple bacterium Thermochromatium (Tch.) tepidum has a closed O-shaped LH1 ring that lacks a gap, and hence the mechanism of photosynthetic quinone transport is unclear. Here we detected light-induced Fourier transform infrared (FTIR) signals responsible for changes of QB and its binding site that accompany photosynthetic quinone reduction in Tch. tepidum and characterized QB and QBH2 marker bands based on their 15N- and 13C-isotopic shifts. Quinone exchanges were monitored using reconstituted photosynthetic membranes comprised of solubilized photosynthetic proteins, membrane lipids, and exogenous ubiquinone (UQ) molecules. In combination with 13C-labeling of the LH1-RC and replacement of native UQ8 by ubiquinones of different tail lengths, we demonstrated that quinone exchanges occur efficiently within the hydrophobic environment of the lipid membrane and depend on the side chain length of UQ. These results strongly indicate that unlike the process in Rba. sphaeroides, quinone transport in Tch. tepidum occurs through the size-restricted hydrophobic channels in the closed LH1 ring and are consistent with structural studies that have revealed narrow hydrophobic channels in the Tch. tepidum LH1 transmembrane region.
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8
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Dai L, Tan LM, Jiang YL, Shi Y, Wang P, Zhang JP, Otomo ZY. Orientation assignment of LH2 and LH1-RC complexes from Thermochromatium tepidum reconstituted in PC liposome and their ultrafast excitation dynamics comparison between in artificial and in natural chromatophores. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.05.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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9
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Ting JJL. Proposal for verifying dipole properties of light-harvesting antennas. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018; 179:134-138. [PMID: 29367148 DOI: 10.1016/j.jphotobiol.2018.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/09/2018] [Accepted: 01/12/2018] [Indexed: 11/26/2022]
Abstract
For light harvesters with a reaction center complex (LH1-RC complex) of three types, we propose an experiment to verify our analysis based upon antenna theories that automatically include the required structural information. Our analysis conforms to the current understanding of light-harvesting antennas in that we can explain known properties of these complexes. We provide an explanation for the functional roles of the notch at the light harvester, a functional role of the polypeptide called PufX or W at the opening, a functional role of the special pair, a reason that the cross section of the light harvester must not be circular, a reason that the light harvester must not be spherical, reasons for the use of dielectric bacteriochlorophylls instead of conductors to make the light harvester, a mechanism to prevent damage from excess sunlight, an advantage of the dimeric form, and reasons for the modular design of nature. Based upon our analysis we provide a mechanism for dimerization. We predict that the dimeric form of light-harvesting complexes is favored under intense sunlight. We further comment upon the classification of the dimeric or S-shape complexes. The S-shape complexes should not be considered as the third type of light harvester but simply as a composite form.
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Löhner A, Cogdell R, Köhler J. Contribution of low-temperature single-molecule techniques to structural issues of pigment-protein complexes from photosynthetic purple bacteria. J R Soc Interface 2018; 15:rsif.2017.0680. [PMID: 29321265 DOI: 10.1098/rsif.2017.0680] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/01/2017] [Indexed: 11/12/2022] Open
Abstract
As the electronic energies of the chromophores in a pigment-protein complex are imposed by the geometrical structure of the protein, this allows the spectral information obtained to be compared with predictions derived from structural models. Thereby, the single-molecule approach is particularly suited for the elucidation of specific, distinctive spectral features that are key for a particular model structure, and that would not be observable in ensemble-averaged spectra due to the heterogeneity of the biological objects. In this concise review, we illustrate with the example of the light-harvesting complexes from photosynthetic purple bacteria how results from low-temperature single-molecule spectroscopy can be used to discriminate between different structural models. Thereby the low-temperature approach provides two advantages: (i) owing to the negligible photobleaching, very long observation times become possible, and more importantly, (ii) at cryogenic temperatures, vibrational degrees of freedom are frozen out, leading to sharper spectral features and in turn to better resolved spectra.
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Affiliation(s)
- Alexander Löhner
- Spectroscopy of Soft Matter, University of Bayreuth, 95440 Bayreuth, Germany
| | - Richard Cogdell
- Institute of Molecular, Cell and Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland
| | - Jürgen Köhler
- Spectroscopy of Soft Matter, University of Bayreuth, 95440 Bayreuth, Germany .,Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, 95440 Bayreuth, Germany
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11
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The C-terminus of PufX plays a key role in dimerisation and assembly of the reaction center light-harvesting 1 complex from Rhodobacter sphaeroides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:795-803. [PMID: 28587931 PMCID: PMC5538271 DOI: 10.1016/j.bbabio.2017.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/31/2017] [Accepted: 06/01/2017] [Indexed: 11/22/2022]
Abstract
In bacterial photosynthesis reaction center-light-harvesting 1 (RC-LH1) complexes trap absorbed solar energy by generating a charge separated state. Subsequent electron and proton transfers form a quinol, destined to diffuse to the cytochrome bc1 complex. In bacteria such as Rhodobacter (Rba.) sphaeroides and Rba. capsulatus the PufX polypeptide creates a channel for quinone/quinol traffic across the LH1 complex that surrounds the RC, and it is therefore essential for photosynthetic growth. PufX also plays a key role in dimerization of the RC-LH1-PufX core complex, and the structure of the Rba. sphaeroides complex shows that the PufX C-terminus, particularly the region from X49-X53, likely mediates association of core monomers. To investigate this putative interaction we analysed mutations PufX R49L, PufX R53L, PufX R49/53L and PufX G52L by measuring photosynthetic growth, fractionation of detergent-solubilised membranes, formation of 2-D crystals and electron microscopy. We show that these mutations do not affect assembly of PufX within the core or photosynthetic growth but they do prevent dimerization, consistent with predictions from the RC-LH1-PufX structure. We obtained low resolution structures of monomeric core complexes with and without PufX, using electron microscopy of negatively stained single particles and 3D reconstruction; the monomeric complex with PufX corresponds to one half of the dimer structure whereas LH1 completely encloses the RC if the gene encoding PufX is deleted. On the basis of the insights gained from these mutagenesis and structural analyses we propose a sequence for assembly of the dimeric RC-LH1-PufX complex.
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12
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Olsen JD, Martin EC, Hunter CN. The PufX quinone channel enables the light-harvesting 1 antenna to bind more carotenoids for light collection and photoprotection. FEBS Lett 2017; 591:573-580. [PMID: 28130884 PMCID: PMC5347945 DOI: 10.1002/1873-3468.12575] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/12/2017] [Accepted: 01/16/2017] [Indexed: 11/30/2022]
Abstract
Photosynthesis in some phototrophic bacteria requires the PufX component of the reaction centre–light‐harvesting 1–PufX (RC‐LH1‐PufX) complex, which creates a pore for quinone/quinol (Q/QH2) exchange across the LH1 barrier surrounding the RC. However, photosynthetic bacteria such as Thermochromatium (T.) tepidum do not require PufX because there are fewer carotenoid binding sites, which creates multiple pores in the LH1 ring for Q/QH2 exchange. We show that an αTrp‐24→Phe alteration of the Rhodobacter (Rba.) sphaeroides LH1 antenna impairs carotenoid binding and allows photosynthetic growth in the absence of PufX. We propose that acquisition of PufX and confining Q/QH2 traffic to a pore adjacent to the RC QB site is an evolutionary upgrade that allows increased LH1 carotenoid content for enhanced light absorption and photoprotection.
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Affiliation(s)
- John D Olsen
- Department of Molecular Biology and Biotechnology, University of Sheffield, UK
| | - Elizabeth C Martin
- Department of Molecular Biology and Biotechnology, University of Sheffield, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, UK
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13
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Kondo T, Chen WJ, Schlau-Cohen GS. Single-Molecule Fluorescence Spectroscopy of Photosynthetic Systems. Chem Rev 2017; 117:860-898. [DOI: 10.1021/acs.chemrev.6b00195] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Toru Kondo
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge Massachusetts 02139, United States
| | - Wei Jia Chen
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge Massachusetts 02139, United States
| | - Gabriela S. Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge Massachusetts 02139, United States
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14
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Mirkovic T, Ostroumov EE, Anna JM, van Grondelle R, Govindjee, Scholes GD. Light Absorption and Energy Transfer in the Antenna Complexes of Photosynthetic Organisms. Chem Rev 2016; 117:249-293. [PMID: 27428615 DOI: 10.1021/acs.chemrev.6b00002] [Citation(s) in RCA: 599] [Impact Index Per Article: 74.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing molecules (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solutions for light harvesting. In this review, we describe the underlying photophysical principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET). First, optical properties of the individual pigment chromophores present in light-harvesting antenna complexes are introduced, and then we examine the collective behavior of pigment-pigment and pigment-protein interactions. The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment molecules. In the latter half of the article, we focus on the light-harvesting complexes of purple bacteria as a model to illustrate the present understanding of the synergetic effects leading to EET optimization of light-harvesting antenna systems while exploring the structure and function of the integral chromophores. We end this review with a brief overview of the energy-transfer dynamics and pathways in the light-harvesting antennas of various photosynthetic organisms.
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Affiliation(s)
- Tihana Mirkovic
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Evgeny E Ostroumov
- Department of Chemistry, Princeton University , Washington Road, Princeton, New Jersey 08544, United States
| | - Jessica M Anna
- Department of Chemistry, University of Pennsylvania , 231 S. 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Govindjee
- Department of Biochemistry, Center of Biophysics & Quantitative Biology, and Department of Plant Biology, University of Illinois at Urbana-Champaign , 265 Morrill Hall, 505 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Gregory D Scholes
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Department of Chemistry, Princeton University , Washington Road, Princeton, New Jersey 08544, United States
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15
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Bína D, Gardian Z, Vácha F, Litvín R. Native FMO-reaction center supercomplex in green sulfur bacteria: an electron microscopy study. PHOTOSYNTHESIS RESEARCH 2016; 128:93-102. [PMID: 26589322 DOI: 10.1007/s11120-015-0205-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 11/12/2015] [Indexed: 06/05/2023]
Abstract
Chlorobaculum tepidum is a representative of green sulfur bacteria, a group of anoxygenic photoautotrophs that employ chlorosomes as the main light-harvesting structures. Chlorosomes are coupled to a ferredoxin-reducing reaction center by means of the Fenna-Matthews-Olson (FMO) protein. While the biochemical properties and physical functioning of all the individual components of this photosynthetic machinery are quite well understood, the native architecture of the photosynthetic supercomplexes is not. Here we report observations of membrane-bound FMO and the analysis of the respective FMO-reaction center complex. We propose the existence of a supercomplex formed by two reaction centers and four FMO trimers based on the single-particle analysis of the complexes attached to native membrane. Moreover, the structure of the photosynthetic unit comprising the chlorosome with the associated pool of RC-FMO supercomplexes is proposed.
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Affiliation(s)
- David Bína
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic.
- Institute of Plant Molecular Biology, Biology Centre CAS, Branišovská 31, 370 05, České Budějovice, Czech Republic.
| | - Zdenko Gardian
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Institute of Plant Molecular Biology, Biology Centre CAS, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - František Vácha
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Institute of Plant Molecular Biology, Biology Centre CAS, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Radek Litvín
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Institute of Plant Molecular Biology, Biology Centre CAS, Branišovská 31, 370 05, České Budějovice, Czech Republic
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16
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Selyanin V, Hauruseu D, Koblížek M. The variability of light-harvesting complexes in aerobic anoxygenic phototrophs. PHOTOSYNTHESIS RESEARCH 2016; 128:35-43. [PMID: 26482589 DOI: 10.1007/s11120-015-0197-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 10/13/2015] [Indexed: 06/05/2023]
Abstract
Light-harvesting capacity was investigated in six species of aerobic anoxygenic phototrophic (AAP) bacteria using absorption spectroscopy, fluorescence emission spectroscopy, and pigment analyses. Aerobically grown AAP cells contained approx. 140-1800 photosynthetic reaction centers per cell, an order of magnitude less than purple non-sulfur bacteria grown semiaerobically. Three of the studied AAP species did not contain outer light-harvesting complexes, and the size of their reaction center core complexes (RC-LH1 core complexes) varied between 29 and 36 bacteriochlorophyll molecules. In AAP species containing accessory antennae, the size was frequently reduced, providing between 5 and 60 additional bacteriochlorophyll molecules. In Roseobacter litoralis, it was found that cells grown at a higher light intensity contained more reaction centers per cell, while the size of the light-harvesting complexes was reduced. The presented results document that AAP species have both the reduced number and size of light-harvesting complexes which is consistent with the auxiliary role of phototrophy in this bacterial group.
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Affiliation(s)
- Vadim Selyanin
- Center Algatech, Institute of Microbiology CAS, 37981, Třeboň, Czech Republic.
| | - Dzmitry Hauruseu
- Center Algatech, Institute of Microbiology CAS, 37981, Třeboň, Czech Republic
| | - Michal Koblížek
- Center Algatech, Institute of Microbiology CAS, 37981, Třeboň, Czech Republic
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17
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Uragami C, Sugai Y, Hanjo K, Sumino A, Fujii R, Nishioka T, Kinoshita I, Dewa T, Nango M, Gardiner AT, Cogdell RJ, Hashimoto H. Observation of hybrid artificial photosynthetic membranes using peripheral and core antennae from two different species of photosynthetic bacteria by AFM and fluorescence micro-spectroscopy. J Photochem Photobiol A Chem 2015. [DOI: 10.1016/j.jphotochem.2015.06.009] [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]
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18
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Patole S, Vasilev C, El-Zubir O, Wang L, Johnson MP, Cadby AJ, Leggett GJ, Hunter CN. Interference lithographic nanopatterning of plant and bacterial light-harvesting complexes on gold substrates. Interface Focus 2015; 5:20150005. [PMID: 26464784 PMCID: PMC4590419 DOI: 10.1098/rsfs.2015.0005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
We describe a facile approach for nanopatterning of photosynthetic light-harvesting complexes over macroscopic areas, and use optical spectroscopy to demonstrate retention of native properties by both site-specifically and non-specifically attached photosynthetic membrane proteins. A Lloyd's mirror dual-beam interferometer was used to expose self-assembled monolayers of amine-terminated alkylthiolates on gold to laser irradiation. Following exposure, photo-oxidized adsorbates were replaced by oligo(ethylene glycol) terminated thiols, and the remaining intact amine-functionalized regions were used for attachment of the major light-harvesting chlorophyll-protein complex from plants, LHCII. These amine patterns could be derivatized with nitrilotriacetic acid (NTA), so that polyhistidine-tagged bacteriochlorophyll-protein complexes from phototrophic bacteria could be attached with a defined surface orientation. By varying parameters such as the angle between the interfering beams and the laser irradiation dose, it was possible to vary the period and widths of NTA and amine-functionalized lines on the surfaces; periods varied from 1200 to 240 nm and linewidths as small as 60 nm (λ/4) were achieved. This level of control over the surface chemistry was reflected in the surface topology of the protein nanostructures imaged by atomic force microscopy; fluorescence imaging and spectral measurements demonstrated that the surface-attached proteins had retained their native functionality.
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Affiliation(s)
- Samson Patole
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Osama El-Zubir
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - Lin Wang
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
- Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK
| | - Matthew P. Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Ashley J. Cadby
- Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK
| | - Graham J. Leggett
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - C. Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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19
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Chandler DE, Strümpfer J, Sener M, Scheuring S, Schulten K. Light harvesting by lamellar chromatophores in Rhodospirillum photometricum. Biophys J 2015; 106:2503-10. [PMID: 24896130 DOI: 10.1016/j.bpj.2014.04.030] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 11/26/2022] Open
Abstract
Purple photosynthetic bacteria harvest light using pigment-protein complexes which are often arranged in pseudo-organelles called chromatophores. A model of a chromatophore from Rhodospirillum photometricum was constructed based on atomic force microscopy data. Molecular-dynamics simulations and quantum-dynamics calculations were performed to characterize the intercomplex excitation transfer network and explore the interplay between close-packing and light-harvesting efficiency.
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Affiliation(s)
- Danielle E Chandler
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Johan Strümpfer
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois; Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Melih Sener
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Simon Scheuring
- U1006 INSERM, Aix-Marseille Université, Parc Scientifique et Technologique de Luminy, 163 avenue de Luminy, 13009 Marseille, France
| | - Klaus Schulten
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois.
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20
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The 17-propionate esterifying variants of bacteriochlorophyll-a and bacteriopheophytin-a in purple photosynthetic bacteria. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 142:244-9. [DOI: 10.1016/j.jphotobiol.2014.12.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/08/2014] [Accepted: 12/11/2014] [Indexed: 02/08/2023]
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21
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Bína D, Gardian Z, Vácha F, Litvín R. Supramolecular organization of photosynthetic membrane proteins in the chlorosome-containing bacterium Chloroflexus aurantiacus. PHOTOSYNTHESIS RESEARCH 2014; 122:13-21. [PMID: 24760483 DOI: 10.1007/s11120-014-0006-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/08/2014] [Indexed: 06/03/2023]
Abstract
The arrangement of core antenna complexes (B808-866-RC) in the cytoplasmic membrane of filamentous phototrophic bacterium Chloroflexus aurantiacus was studied by electron microscopy in cultures from different light conditions. A typical nearest-neighbor center-to-center distance of ~18 nm was found, implying less protein crowding compared to membranes of purple bacteria. A mean RC:chlorosome ratio of 11 was estimated for the occupancy of the membrane directly underneath each chlorosome, based on analysis of chlorosome dimensions and core complex distribution. Also presented are results of single-particle analysis of core complexes embedded in the native membrane.
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Affiliation(s)
- David Bína
- Faculty of Science, University of South Bohemia, Branišovská 31, 37005, České Budějovice, Czech Republic,
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22
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Olsen JD, Adams PG, Jackson PJ, Dickman MJ, Qian P, Hunter CN. Aberrant assembly complexes of the reaction center light-harvesting 1 PufX (RC-LH1-PufX) core complex of Rhodobacter sphaeroides imaged by atomic force microscopy. J Biol Chem 2014; 289:29927-36. [PMID: 25193660 PMCID: PMC4208002 DOI: 10.1074/jbc.m114.596585] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
In the purple phototrophic bacterium Rhodobacter sphaeroides, many protein complexes congregate within the membrane to form operational photosynthetic units consisting of arrays of light-harvesting LH2 complexes and monomeric and dimeric reaction center (RC)-light-harvesting 1 (LH1)-PufX “core” complexes. Each half of a dimer complex consists of a RC surrounded by 14 LH1 αβ subunits, with two bacteriochlorophylls (Bchls) sandwiched between each αβ pair of transmembrane helices. We used atomic force microscopy (AFM) to investigate the assembly of single molecules of the RC-LH1-PufX complex using membranes prepared from LH2-minus mutants. When the RC and PufX components were also absent, AFM revealed a series of LH1 variants where the repeating α1β1(Bchl)2 units had formed rings of variable size, ellipses, and spirals and also arcs that could be assembly products. The spiral complexes occur when the LH1 ring has failed to close, and short arcs are suggestive of prematurely terminated LH1 complex assembly. In the absence of RCs, we occasionally observed captive proteins enclosed by the LH1 ring. When production of LH1 units was restricted by lowering the relative levels of the cognate pufBA transcript, we imaged a mixture of complete RC-LH1 core complexes, empty LH1 rings, and isolated RCs, leading us to conclude that once a RC associates with the first α1β1(Bchl)2 subunit, cooperative associations between subsequent subunits and the RC tend to drive LH1 ring assembly to completion.
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Affiliation(s)
- John D Olsen
- From the Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom and
| | - Peter G Adams
- From the Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom and
| | - Philip J Jackson
- From the Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom and the Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield, S1 3JD, United Kingdom
| | - Mark J Dickman
- the Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield, S1 3JD, United Kingdom
| | - Pu Qian
- From the Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom and
| | - C Neil Hunter
- From the Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom and
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23
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Li Y, Kimura Y, Arikawa T, Wang-Otomo ZY, Ohno T. ATR–FTIR Detection of Metal-Sensitive Structural Changes in the Light-Harvesting 1 Reaction Center Complex from the Thermophilic Purple Sulfur Bacterium Thermochromatium tepidum. Biochemistry 2013; 52:9001-8. [DOI: 10.1021/bi401033y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yong Li
- Department
of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
| | - Yukihiro Kimura
- Department
of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
| | - Teruhisa Arikawa
- Department
of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
| | | | - Takashi Ohno
- Department
of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
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24
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Qian P, Papiz MZ, Jackson PJ, Brindley AA, Ng IW, Olsen JD, Dickman MJ, Bullough PA, Hunter CN. Three-Dimensional Structure of the Rhodobacter sphaeroides RC-LH1-PufX Complex: Dimerization and Quinone Channels Promoted by PufX. Biochemistry 2013; 52:7575-85. [DOI: 10.1021/bi4011946] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pu Qian
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Firth Court, Sheffield S10 2TN, United Kingdom
| | - Miroslav Z. Papiz
- Institute
of Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom
| | - Philip J. Jackson
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Firth Court, Sheffield S10 2TN, United Kingdom
- ChELSI
Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
| | - Amanda A. Brindley
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Firth Court, Sheffield S10 2TN, United Kingdom
| | - Irene W. Ng
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Firth Court, Sheffield S10 2TN, United Kingdom
| | - John D. Olsen
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Firth Court, Sheffield S10 2TN, United Kingdom
| | - Mark J. Dickman
- ChELSI
Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
| | - Per A. Bullough
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Firth Court, Sheffield S10 2TN, United Kingdom
| | - C. Neil Hunter
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Firth Court, Sheffield S10 2TN, United Kingdom
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25
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Adams PG, Cadby AJ, Robinson B, Tsukatani Y, Tank M, Wen J, Blankenship RE, Bryant DA, Hunter CN. Comparison of the physical characteristics of chlorosomes from three different phyla of green phototrophic bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:1235-44. [PMID: 23867748 DOI: 10.1016/j.bbabio.2013.07.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 07/05/2013] [Accepted: 07/08/2013] [Indexed: 11/18/2022]
Abstract
Chlorosomes, the major antenna complexes in green sulphur bacteria, filamentous anoxygenic phototrophs, and phototrophic acidobacteria, are attached to the cytoplasmic side of the inner cell membrane and contain thousands of bacteriochlorophyll (BChl) molecules that harvest light and channel the energy to membrane-bound reaction centres. Chlorosomes from phototrophs representing three different phyla, Chloroflexus (Cfx.) aurantiacus, Chlorobaculum (Cba.) tepidum and the newly discovered "Candidatus (Ca.) Chloracidobacterium (Cab.) thermophilum" were analysed using PeakForce Tapping atomic force microscopy (PFT-AFM). Gentle PFT-AFM imaging in buffered solutions that maintained the chlorosomes in a near-native state revealed ellipsoids of variable size, with surface bumps and undulations that differ between individual chlorosomes. Cba. tepidum chlorosomes were the largest (133×57×36nm; 141,000nm(3) volume), compared with chlorosomes from Cfx. aurantiacus (120×44×30nm; 84,000nm(3)) and Ca. Cab. thermophilum (99×40×31nm; 65,000nm(3)). Reflecting the contributions of thousands of pigment-pigment stacking interactions to the stability of these supramolecular assemblies, analysis by nanomechanical mapping shows that chlorosomes are highly stable and that their integrity is disrupted only by very strong forces of 1000-2000pN. AFM topographs of Ca. Cab. thermophilum chlorosomes that had retained their attachment to the cytoplasmic membrane showed that this membrane dynamically changes shape and is composed of protrusions of up to 30nm wide and 6nm above the mica support, possibly representing different protein domains. Spectral imaging revealed significant heterogeneity in the fluorescence emission of individual chlorosomes, likely reflecting the variations in BChl c homolog composition and internal arrangements of the stacked BChls within each chlorosome.
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Affiliation(s)
- Peter G Adams
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
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26
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Harrold JW, Woronowicz K, Lamptey JL, Awong J, Baird J, Moshar A, Vittadello M, Falkowski PG, Niederman RA. Functional Interfacing of Rhodospirillum rubrum Chromatophores to a Conducting Support for Capture and Conversion of Solar Energy. J Phys Chem B 2013; 117:11249-59. [DOI: 10.1021/jp402108s] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- John W. Harrold
- Department of Chemistry and Chemical
Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey
08854, United States
| | - Kamil Woronowicz
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, 604 Allison
Road, Piscataway, New Jersey 08854-8082, United States
| | - Joana L. Lamptey
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, 604 Allison
Road, Piscataway, New Jersey 08854-8082, United States
| | - John Awong
- Energy Nanotechnology and Materials
Chemistry Lab, Medgar Evers College of the City University of New York, 1638 Bedford Avenue, Brooklyn, New York 11225, United States
| | - James Baird
- Energy Nanotechnology and Materials
Chemistry Lab, Medgar Evers College of the City University of New York, 1638 Bedford Avenue, Brooklyn, New York 11225, United States
| | - Amir Moshar
- Asylum Research, 6310 Hollister Avenue, Santa Barbara, California 93117, United
States
| | - Michele Vittadello
- Energy Nanotechnology and Materials
Chemistry Lab, Medgar Evers College of the City University of New York, 1638 Bedford Avenue, Brooklyn, New York 11225, United States
| | - Paul G. Falkowski
- Department of Chemistry and Chemical
Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey
08854, United States
- Institute for Marine
and Coastal Sciences, Rutgers, The State University of New Jersey, 71 Dudley Road, New Brunswick, New Jersey
08901, United States
| | - Robert A. Niederman
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, 604 Allison
Road, Piscataway, New Jersey 08854-8082, United States
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27
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Structural implications of hydrogen-bond energetics in membrane proteins revealed by high-pressure spectroscopy. Biophys J 2013; 103:2352-60. [PMID: 23283234 DOI: 10.1016/j.bpj.2012.10.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 10/09/2012] [Accepted: 10/23/2012] [Indexed: 11/23/2022] Open
Abstract
The light-harvesting 1 (LH1) integral membrane complex of Rhodobacter sphaeroides provides a convenient model system in which to examine the poorly understood role of hydrogen bonds (H-bonds) as stabilizing factors in membrane protein complexes. We used noncovalently bound arrays of bacteriochlorophyll chromophores within native and genetically modified variants of LH1 complexes to monitor local changes in the chromophore binding sites induced by externally applied hydrostatic pressure. Whereas membrane-bound complexes demonstrated very high resilience to pressures reaching 2.1 GPa, characteristic discontinuous shifts and broadenings of the absorption spectra were observed around 1 GPa for detergent-solubilized proteins, in similarity to those observed when specific (α or β) H-bonds between the chromophores and the surrounding protein were selectively removed by mutagenesis. These pressure effects, which were reversible upon decompression, allowed us to estimate the rupture energies of H-bonds to the chromophores in LH1 complexes. A quasi-independent, additive role of H-bonds in the α- and β-sublattices in reinforcing the wild-type LH1 complex was established. A comparison of a reaction-center-deficient LH1 complex with complexes containing reaction centers also demonstrated a stabilizing effect of the reaction center. This study thus provides important insights into the design principles of natural photosynthetic complexes.
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28
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Liu LN, Scheuring S. Investigation of photosynthetic membrane structure using atomic force microscopy. TRENDS IN PLANT SCIENCE 2013; 18:277-86. [PMID: 23562040 DOI: 10.1016/j.tplants.2013.03.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 02/21/2013] [Accepted: 03/01/2013] [Indexed: 05/26/2023]
Abstract
Photosynthetic processes, including light capture, electron transfer, and energy conversion, are not only ensured by the activities of individual photosynthetic complexes but also substantially determined and regulated by the composition and assembly of the overall photosynthetic apparatus at the supramolecular level. In recent years, atomic force microscopy (AFM) has matured as a unique and powerful tool for directly assessing the supramolecular assembly of integral membrane protein complexes in their native membrane environment at submolecular resolution. This review highlights the major contributions and advances of AFM studies to our understanding of the structure of the bacterial photosynthetic machinery and its regulatory arrangement during chromatic adaptation. AFM topographs of other biological membrane systems and potential future applications of AFM are also discussed.
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Affiliation(s)
- Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK.
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29
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Semchonok DA, Chauvin JP, Frese RN, Jungas C, Boekema EJ. Structure of the dimeric RC-LH1-PufX complex from Rhodobaca bogoriensis investigated by electron microscopy. Philos Trans R Soc Lond B Biol Sci 2013; 367:3412-9. [PMID: 23148268 DOI: 10.1098/rstb.2012.0063] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Electron microscopy and single-particle averaging were performed on isolated reaction centre (RC)-antenna complexes (RC-LH1-PufX complexes) of Rhodobaca bogoriensis strain LBB1, with the aim of establishing the LH1 antenna conformation, and, in particular, the structural role of the PufX protein. Projection maps of dimeric complexes were obtained at 13 Å resolution and show the positions of the 2 × 14 LH1 α- and β-subunits. This new dimeric complex displays two open, C-shaped LH1 aggregates of 13 αβ polypeptides partially surrounding the RCs plus two LH1 units forming the dimer interface in the centre. Between the interface and the two half rings are two openings on each side. Next to the openings, there are four additional densities present per dimer, considered to be occupied by four copies of PufX. The position of the RC in our model was verified by comparison with RC-LH1-PufX complexes in membranes. Our model differs from previously proposed configurations for Rhodobacter species in which the LH1 ribbon is continuous in the shape of an S, and the stoichiometry is of one PufX per RC.
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Affiliation(s)
- Dmitry A Semchonok
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, Groningen, The Netherlands
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30
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Abstract
This review outlines the recent progress made in developing more accurate and efficient solutions to model electrostatics in systems comprised of bio-macromolecules and nano-objects, the last one referring to objects that do not have biological function themselves but nowadays are frequently used in biophysical and medical approaches in conjunction with bio-macromolecules. The problem of modeling macromolecular electrostatics is reviewed from two different angles: as a mathematical task provided the specific definition of the system to be modeled and as a physical problem aiming to better capture the phenomena occurring in the real experiments. In addition, specific attention is paid to methods to extend the capabilities of the existing solvers to model large systems toward applications of calculations of the electrostatic potential and energies in molecular motors, mitochondria complex, photosynthetic machinery and systems involving large nano-objects.
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Böhm PS, Southall J, Cogdell RJ, Köhler J. Single-Molecule Spectroscopy on RC-LH1 Complexes of Rhodopseudomonas acidophila Strain 10050. J Phys Chem B 2013; 117:3120-6. [DOI: 10.1021/jp4005218] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul S. Böhm
- Experimental Physics IV and
Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, 95440 Bayreuth, Germany
| | - June Southall
- Institute of Molecular, Cell
and Systems Biology, College of Medical Veterinary and Life Sciences,
Biomedical Research Building, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Richard J. Cogdell
- Institute of Molecular, Cell
and Systems Biology, College of Medical Veterinary and Life Sciences,
Biomedical Research Building, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Jürgen Köhler
- Experimental Physics IV and
Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, 95440 Bayreuth, Germany
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32
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Tan SC, Crouch LI, Mahajan S, Jones MR, Welland ME. Increasing the open-circuit voltage of photoprotein-based photoelectrochemical cells by manipulation of the vacuum potential of the electrolytes. ACS NANO 2012; 6:9103-9109. [PMID: 23009071 DOI: 10.1021/nn303333e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The innately highly efficient light-powered separation of charge that underpins natural photosynthesis can be exploited for applications in photoelectrochemistry by coupling nanoscale protein photoreaction centers to man-made electrodes. Planar photoelectrochemical cells employing purple bacterial reaction centers have been constructed that produce a direct current under continuous illumination and an alternating current in response to discontinuous illumination. The present work explored the basis of the open-circuit voltage (V(OC)) produced by such cells with reaction center/antenna (RC-LH1) proteins as the photovoltaic component. It was established that an up to ~30-fold increase in V(OC) could be achieved by simple manipulation of the electrolyte connecting the protein to the counter electrode, with an approximately linear relationship being observed between the vacuum potential of the electrolyte and the resulting V(OC). We conclude that the V(OC) of such a cell is dependent on the potential difference between the electrolyte and the photo-oxidized bacteriochlorophylls in the reaction center. The steady-state short-circuit current (J(SC)) obtained under continuous illumination also varied with different electrolytes by a factor of ~6-fold. The findings demonstrate a simple way to boost the voltage output of such protein-based cells into the hundreds of millivolts range typical of dye-sensitized and polymer-blend solar cells, while maintaining or improving the J(SC). Possible strategies for further increasing the V(OC) of such protein-based photoelectrochemical cells through protein engineering are discussed.
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Affiliation(s)
- Swee Ching Tan
- Nanoscience Centre, University of Cambridge, 11 JJ Thomson Avenue, Cambridge CB3 0FF, UK.
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33
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Kimura Y, Inada Y, Numata T, Arikawa T, Li Y, Zhang JP, Wang ZY, Ohno T. Metal cations modulate the bacteriochlorophyll–protein interaction in the light-harvesting 1 core complex from Thermochromatium tepidum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1022-9. [DOI: 10.1016/j.bbabio.2012.03.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/07/2012] [Accepted: 03/11/2012] [Indexed: 11/16/2022]
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34
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Kondo M, Iida K, Dewa T, Tanaka H, Ogawa T, Nagashima S, Nagashima KVP, Shimada K, Hashimoto H, Gardiner AT, Cogdell RJ, Nango M. Photocurrent and electronic activities of oriented-His-tagged photosynthetic light-harvesting/reaction center core complexes assembled onto a gold electrode. Biomacromolecules 2012; 13:432-8. [PMID: 22239547 DOI: 10.1021/bm201457s] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A polyhistidine (His) tag was fused to the C- or N-terminus of the light-harvesting (LH1)-α chain of the photosynthetic antenna core complex (LH1-RC) from Rhodobacter sphaeroides to allow immobilization of the complex on a solid substrate with defined orientation. His-tagged LH1-RCs were adsorbed onto a gold electrode modified with Ni-NTA. The LH1-RC with the C-terminal His-tag (C-His LH1-RC) on the modified electrode produced a photovoltaic response upon illumination. Electron transfer is unidirectional within the RC and starts when the bacteriochlorophyll a dimer in the RC is activated by light absorbed by LH1. The LH1-RC with the N-terminal His-tag (N-His LH1-RC) produced very little or no photocurrent upon illumination at any wavelength. The conductivity of the His-tagged LH1-RC was measured with point-contact current imaging atomic force microscopy, indicating that 60% of the C-His LH1-RC are correctly oriented (N-His 63%). The oriented C-His LH1-RC or N-His LH1-RC showed semiconductive behavior, that is, had the opposite orientation. These results indicate that the His-tag successfully controlled the orientation of the RC on the solid substrate, and that the RC produced photocurrent depending upon the orientation on the electrode.
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Affiliation(s)
- Masaharu Kondo
- Department of Frontier Materials, Tsukuri College, Graduate School of Engineering, Nagoya Institute of Technology , Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
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Crouch LI, Jones MR. Cross-species investigation of the functions of the Rhodobacter PufX polypeptide and the composition of the RC-LH1 core complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:336-52. [PMID: 22079525 DOI: 10.1016/j.bbabio.2011.10.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 10/24/2011] [Accepted: 10/27/2011] [Indexed: 10/15/2022]
Abstract
In well-characterised species of the Rhodobacter (Rba.) genus of purple photosynthetic bacteria it is known that the photochemical reaction centre (RC) is intimately-associated with an encircling LH1 antenna pigment protein, and this LH1 antenna is prevented from completely surrounding the RC by a single copy of the PufX protein. In Rba. veldkampii only monomeric RC-LH1 complexes are assembled in the photosynthetic membrane, whereas in Rba. sphaeroides and Rba. blasticus a dimeric form is also assembled in which two RCs are surrounded by an S-shaped LH1 antenna. The present work established that dimeric RC-LH1 complexes can also be isolated from Rba. azotoformans and Rba. changlensis, but not from Rba. capsulatus or Rba. vinaykumarii. The compositions of the monomers and dimers isolated from these four species of Rhodobacter were similar to those of the well-characterised RC-LH1 complexes present in Rba. sphaeroides. Pigment proteins were also isolated from strains of Rba. sphaeroides expressing chimeric RC-LH1 complexes. Replacement of either the Rba. sphaeroides LH1 antenna or PufX with its counterpart from Rba. capsulatus led to a loss of the dimeric form of the RC-LH1 complex, but the monomeric form had a largely unaltered composition, even in strains in which the expression level of LH1 relative to the RC was reduced. The chimeric RC-LH1 complexes were also functional, supporting bacterial growth under photosynthetic conditions. The findings help to tease apart the different functions of PufX in different species of Rhodobacter, and a specific protein structural arrangement that allows PufX to fulfil these three functions is proposed.
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Zheng Q, Zhang R, Koblížek M, Boldareva EN, Yurkov V, Yan S, Jiao N. Diverse arrangement of photosynthetic gene clusters in aerobic anoxygenic phototrophic bacteria. PLoS One 2011; 6:e25050. [PMID: 21949847 PMCID: PMC3176799 DOI: 10.1371/journal.pone.0025050] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 08/23/2011] [Indexed: 11/21/2022] Open
Abstract
Background Aerobic anoxygenic photototrophic (AAP) bacteria represent an important group of marine microorganisms inhabiting the euphotic zone of the ocean. They harvest light using bacteriochlorophyll (BChl) a and are thought to be important players in carbon cycling in the ocean. Methodology/Principal Findings Aerobic anoxygenic phototrophic (AAP) bacteria represent an important part of marine microbial communities. Their photosynthetic apparatus is encoded by a number of genes organized in a so-called photosynthetic gene cluster (PGC). In this study, the organization of PGCs was analyzed in ten AAP species belonging to the orders Rhodobacterales, Sphingomonadales and the NOR5/OM60 clade. Sphingomonadales contained comparatively smaller PGCs with an approximately size of 39 kb whereas the average size of PGCs in Rhodobacterales and NOR5/OM60 clade was about 45 kb. The distribution of four arrangements, based on the permutation and combination of the two conserved regions bchFNBHLM-LhaA-puhABC and crtF-bchCXYZ, does not correspond to the phylogenetic affiliation of individual AAP bacterial species. While PGCs of all analyzed species contained the same set of genes for bacteriochlorophyll synthesis and assembly of photosynthetic centers, they differed largely in the carotenoid biosynthetic genes. Spheroidenone, spirilloxanthin, and zeaxanthin biosynthetic pathways were found in each clade respectively. All of the carotenoid biosynthetic genes were found in the PGCs of Rhodobacterales, however Sphingomonadales and NOR5/OM60 strains contained some of the carotenoid biosynthetic pathway genes outside of the PGC. Conclusions/Significance Our investigations shed light on the evolution and functional implications in PGCs of marine aerobic anoxygenic phototrophs, and support the notion that AAP are a heterogenous physiological group phylogenetically scattered among Proteobacteria.
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Affiliation(s)
- Qiang Zheng
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Rui Zhang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Michal Koblížek
- Institute of Microbiology CAS, Opatovický mlýn, Třeboň, Czech Republic
| | | | - Vladimir Yurkov
- Department of Microbiology, University of Manitoba, Winnipeg, Canada
| | - Shi Yan
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
- * E-mail:
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Şener M, Strümpfer J, Hsin J, Chandler D, Scheuring S, Hunter CN, Schulten K. Förster energy transfer theory as reflected in the structures of photosynthetic light-harvesting systems. Chemphyschem 2011; 12:518-31. [PMID: 21344591 DOI: 10.1002/cphc.201000944] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Förster’s theory of resonant energy transfer underlies a fundamental process in nature, namely the harvesting of sunlight by photosynthetic life forms. The theoretical framework developed by Förster and others describes how electronic excitation migrates in the photosynthetic apparatus of plants, algae, and bacteria from light absorbing pigments to reaction centers where light energy is utilized for the eventual conversion into chemical energy. The demand for highest possible efficiency of light harvesting appears to have shaped the evolution of photosynthetic species from bacteria to plants which, despite a great variation in architecture, display common structural themes founded on the quantum physics of energy transfer as described first by Förster. Herein, Förster’s theory of excitation transfer is summarized, including recent extensions, and the relevance of the theory to photosynthetic systems as evolved in purple bacteria, cyanobacteria, and plants is demonstrated. Förster’s energy transfer formula, as used widely today in many fields of science, is also derived.
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Affiliation(s)
- Melih Şener
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Sumino A, Dewa T, Takeuchi T, Sugiura R, Sasaki N, Misawa N, Tero R, Urisu T, Gardiner AT, Cogdell RJ, Hashimoto H, Nango M. Construction and structural analysis of tethered lipid bilayer containing photosynthetic antenna proteins for functional analysis. Biomacromolecules 2011; 12:2850-8. [PMID: 21650465 DOI: 10.1021/bm200585y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The construction and structural analysis of a tethered planar lipid bilayer containing bacterial photosynthetic membrane proteins, light-harvesting complex 2 (LH2), and light-harvesting core complex (LH1-RC) is described and establishes this system as an experimental platform for their functional analysis. The planar lipid bilayer containing LH2 and/or LH1-RC complexes was successfully formed on an avidin-immobilized coverglass via an avidin-biotin linkage. Atomic force microscopy (AFM) showed that a smooth continuous membrane was formed there. Lateral diffusion of these membrane proteins, observed by a fluorescence recovery after photobleaching (FRAP), is discussed in terms of the membrane architecture. Energy transfer from LH2 to LH1-RC within the tethered membrane was observed by steady-state fluorescence spectroscopy, indicating that the tethered membrane can mimic the natural situation.
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Affiliation(s)
- Ayumi Sumino
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
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Adams PG, Mothersole DJ, Ng IW, Olsen JD, Hunter CN. Monomeric RC-LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:1044-55. [PMID: 21663730 DOI: 10.1016/j.bbabio.2011.05.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 05/18/2011] [Accepted: 05/19/2011] [Indexed: 10/18/2022]
Abstract
In the model photosynthetic bacterium Rhodobacter sphaeroides domains of light-harvesting 2 (LH2) complexes surround and interconnect dimeric reaction centre-light-harvesting 1-PufX (RC-LH1-PufX) 'core' complexes, forming extensive networks for energy transfer and trapping. These complexes are housed in spherical intracytoplasmic membranes (ICMs), which are assembled in a stepwise process where biosynthesis of core complexes tends to dominate the early stages of membrane invagination. The kinetics of LH2 assembly were measured in PufX mutants that assemble monomeric core complexes, as a consequence of either a twelve-residue N-terminal truncation of PufX (PufXΔ12) or the complete removal of PufX (PufX(-)). Lower rates of LH2 assembly and retarded maturation of membrane invagination were observed for the larger and less curved ICM from the PufX(-) mutant, consistent with the proposition that local membrane curvature, initiated by arrays of bent RC-LH1-PufX dimers, creates a favourable environment for stable assembly of LH2 complexes. Transmission electron microscopy and high-resolution atomic force microscopy were used to examine ICM morphology and membrane protein organisation in these mutants. Some partitioning of core and LH2 complexes was observed in PufX(-) membranes, resulting in locally ordered clusters of monomeric RC-LH1 complexes. The distribution of core and LH2 complexes in the three types of membrane examined is consistent with previous models of membrane curvature and domain formation (Frese et al., 2008), which demonstrated that a combination of crowding and asymmetries in sizes and shapes of membrane protein complexes drives membrane organisation.
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Affiliation(s)
- Peter G Adams
- Department of Molecular Biology and Biochemistry, University of Sheffield, United Kingdom
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40
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Odahara T, Ishii N, Ooishi A, Honda S, Uedaira H, Hara M, Miyake J. Thermostability of Rhodopseudomonas viridis and Rhodospirillum rubrum chromatophores reflecting physiological conditions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1645-53. [DOI: 10.1016/j.bbamem.2011.02.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 01/24/2011] [Accepted: 02/15/2011] [Indexed: 11/29/2022]
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41
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Selao TT, Branca R, Chae PS, Lehtiö J, Gellman SH, Rasmussen SGF, Nordlund S, Norén A. Identification of chromatophore membrane protein complexes formed under different nitrogen availability conditions in Rhodospirillum rubrum. J Proteome Res 2011; 10:2703-14. [PMID: 21443180 DOI: 10.1021/pr100838x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The chromatophore membrane of the photosynthetic diazotroph Rhodospirillum rubrum is of vital importance for a number of central processes, including nitrogen fixation. Using a novel amphiphile, we have identified protein complexes present under different nitrogen availability conditions by the use of two-dimensional Blue Native/SDS-PAGE and NSI-LC-LTQ-Orbitrap mass spectrometry. We have identified several membrane protein complexes, including components of the ATP synthase, reaction center, light harvesting, and NADH dehydrogenase complexes. Additionally, we have identified differentially expressed proteins, such as subunits of the succinate dehydrogenase complex and other TCA cycle enzymes that are usually found in the cytosol, thus hinting at a possible association to the membrane in response to nitrogen deficiency. We propose a redox sensing mechanism that can influence the membrane subproteome in response to nitrogen availability.
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Affiliation(s)
- Tiago Toscano Selao
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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42
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Kimura Y, Inada Y, Yu LJ, Wang ZY, Ohno T. A Spectroscopic Variant of the Light-Harvesting 1 Core Complex from the Thermophilic Purple Sulfur Bacterium Thermochromatium tepidum. Biochemistry 2011; 50:3638-48. [DOI: 10.1021/bi200278u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yukihiro Kimura
- Organization of Advanced Science and Technology, Kobe University, Nada, Kobe 657-8501, Japan
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
| | - Yuta Inada
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
| | - Long-Jiang Yu
- Faculty of Science, Ibaraki University, Bunkyo, Mito 310-8512, Japan
| | - Zheng-Yu Wang
- Faculty of Science, Ibaraki University, Bunkyo, Mito 310-8512, Japan
| | - Takashi Ohno
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University, Nada, Kobe 657-8501, Japan
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43
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Ratcliffe EC, Tunnicliffe RB, Ng IW, Adams PG, Qian P, Holden-Dye K, Jones MR, Williamson MP, Hunter CN. Experimental evidence that the membrane-spanning helix of PufX adopts a bent conformation that facilitates dimerisation of the Rhodobacter sphaeroides RC-LH1 complex through N-terminal interactions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:95-107. [PMID: 20937243 DOI: 10.1016/j.bbabio.2010.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 09/27/2010] [Accepted: 10/04/2010] [Indexed: 10/19/2022]
Abstract
The PufX polypeptide is an integral component of some photosynthetic bacterial reaction center-light harvesting 1 (RC-LH1) core complexes. Many aspects of the structure of PufX are unresolved, including the conformation of its long membrane-spanning helix and whether C-terminal processing occurs. In the present report, NMR data recorded on the Rhodobacter sphaeroides PufX in a detergent micelle confirmed previous conclusions derived from equivalent data obtained in organic solvent, that the α-helix of PufX adopts a bent conformation that would allow the entire helix to reside in the membrane interior or at its surface. In support of this, it was found through the use of site-directed mutagenesis that increasing the size of a conserved glycine on the inside of the bend in the helix was not tolerated. Possible consequences of this bent helical structure were explored using a series of N-terminal deletions. The N-terminal sequence ADKTIFNDHLN on the cytoplasmic face of the membrane was found to be critical for the formation of dimers of the RC-LH1 complex. It was further shown that the C-terminus of PufX is processed at an early stage in the development of the photosynthetic membrane. A model in which two bent PufX polypeptides stabilise a dimeric RC-LH1 complex is presented, and it is proposed that the N-terminus of PufX from one half of the dimer engages in electrostatic interactions with charged residues on the cytoplasmic surface of the LH1α and β polypeptides on the other half of the dimer.
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Affiliation(s)
- Emma C Ratcliffe
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
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44
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Liu LN, Sturgis JN, Scheuring S. Native architecture of the photosynthetic membrane from Rhodobacter veldkampii. J Struct Biol 2010; 173:138-45. [PMID: 20797440 DOI: 10.1016/j.jsb.2010.08.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 08/18/2010] [Accepted: 08/19/2010] [Indexed: 11/27/2022]
Abstract
The photosynthetic membrane in purple bacteria contains several pigment-protein complexes that assure light capture and establishment of the chemiosmotic gradient. The bioenergetic tasks of the photosynthetic membrane require the strong interaction between these various complexes. In the present work, we acquired the first images of the native outer membrane architecture and the supramolecular organization of the photosynthetic apparatus in vesicular chromatophores of Rhodobacter (Rb.) veldkampii. Mixed with LH2 (light-harvesting complex 2) rings, the PufX-containing LH1-RC (light-harvesting complex 1--reaction center) core complexes appear as C-shaped monomers, with random orientations in the photosynthetic membrane. Within the LH1 fence surrounding the RC, a remarkable gap that is probably occupied (or partially occupied) by PufX is visualized. Sequence alignment revealed that one specific region in PufX may be essential for PufX-induced core dimerization. In this region of ten amino acids in length all Rhodobacter species had five conserved amino acids, with the exception of Rb. veldkampii. Our findings provide direct evidence that the presence of PufX in Rb. veldkampii does not directly govern the dimerization of LH1-RC core complexes in the native membrane. It is indicated, furthermore, that the high membrane curvature of Rb. veldkampii chromatophores (Rb. veldkampii features equally small vesicular chromatophores alike Rb. sphaeroides) is not due to membrane bending induced by dimeric RC-LH1-PufX cores, as it has been proposed in Rb. sphaeroides.
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Affiliation(s)
- Lu-Ning Liu
- Institut Curie, U1006 INSERM, UMR168 CNRS, 26 Rue d'Ulm, 75248 Paris, France
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45
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Şener M, Strümpfer J, Timney JA, Freiberg A, Hunter CN, Schulten K. Photosynthetic vesicle architecture and constraints on efficient energy harvesting. Biophys J 2010; 99:67-75. [PMID: 20655834 PMCID: PMC2895385 DOI: 10.1016/j.bpj.2010.04.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 03/16/2010] [Accepted: 04/05/2010] [Indexed: 11/24/2022] Open
Abstract
Photosynthetic chromatophore vesicles found in some purple bacteria constitute one of the simplest light-harvesting systems in nature. The overall architecture of chromatophore vesicles and the structural integration of vesicle function remain poorly understood despite structural information being available on individual constituent proteins. An all-atom structural model for an entire chromatophore vesicle is presented, which improves upon earlier models by taking into account the stoichiometry of core and antenna complexes determined by the absorption spectrum of intact vesicles in Rhodobacter sphaeroides, as well as the well-established curvature-inducing properties of the dimeric core complex. The absorption spectrum of low-light-adapted vesicles is shown to correspond to a light-harvesting-complex 2 to reaction center ratio of 3:1. A structural model for a vesicle consistent with this stoichiometry is developed and used in the computation of excitonic properties. Considered also is the packing density of antenna and core complexes that is high enough for efficient energy transfer and low enough for quinone diffusion from reaction centers to cytochrome bc(1) complexes.
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Affiliation(s)
- Melih Şener
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Johan Strümpfer
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - John A. Timney
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Arvi Freiberg
- Institute of Physics, University of Tartu, Tartu, Estonia
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - C. Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Klaus Schulten
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
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Facey SJ, Kuhn A. Biogenesis of bacterial inner-membrane proteins. Cell Mol Life Sci 2010; 67:2343-62. [PMID: 20204450 PMCID: PMC11115511 DOI: 10.1007/s00018-010-0303-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 02/01/2010] [Accepted: 02/03/2010] [Indexed: 11/26/2022]
Abstract
All cells must traffic proteins into and across their membranes. In bacteria, several pathways have evolved to enable protein transfer across the inner membrane, the periplasm, and the outer membrane. The major route of protein translocation in and across the cytoplasmic membrane is the general secretion pathway (Sec-pathway). The biogenesis of membrane proteins not only requires protein translocation but also coordinated targeting to the membrane beforehand and folding and assembly into their protein complexes afterwards to function properly in the cell. All these processes are responsible for the biogenesis of membrane proteins that mediate essential functions of the cell such as selective transport, energy conversion, cell division, extracellular signal sensing, and motility. This review will highlight the most recent developments on the structure and function of bacterial membrane proteins, focusing on the journey that integral membrane proteins take to find their final destination in the inner membrane.
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Affiliation(s)
- Sandra J. Facey
- Institute of Microbiology, University of Hohenheim, 70599 Stuttgart, Germany
| | - Andreas Kuhn
- Institute of Microbiology, University of Hohenheim, 70599 Stuttgart, Germany
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47
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Orsini F, Santacroce M, Arosio P, Sacchi VF. Observing Xenopus laevis oocyte plasma membrane by atomic force microscopy. Methods 2010; 51:106-13. [DOI: 10.1016/j.ymeth.2009.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 12/02/2009] [Accepted: 12/02/2009] [Indexed: 10/20/2022] Open
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Hsin J, Chandler DE, Gumbart J, Harrison CB, Şener M, Strumpfer J, Schulten K. Self-assembly of photosynthetic membranes. Chemphyschem 2010; 11:1154-9. [PMID: 20183845 PMCID: PMC3086839 DOI: 10.1002/cphc.200900911] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Indexed: 11/08/2022]
Abstract
Bacterial photosynthetic membranes, also known as chromatophores, are tightly packed with integral membrane proteins that work together to carry out photosynthesis. Chromatophores display a wide range of cellular morphologies; spherical, tubular, and lamellar chromatophores have all been observed in different bacterial species, or with different protein constituents. Through recent computational modeling and simulation, it has been demonstrated that the light-harvesting complexes abundant in chromatophores induce local membrane curvature via multiple mechanisms. These protein complexes assemble to generate a global curvature and sculpt the chromatophores into various cellular-scale architectures.
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Affiliation(s)
- Jen Hsin
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Danielle E. Chandler
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
| | - James Gumbart
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
| | | | - Melih Şener
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Johan Strumpfer
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Klaus Schulten
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, USA
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49
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Pandit A, Buda F, van Gammeren AJ, Ganapathy S, de Groot HJM. Selective Chemical Shift Assignment of Bacteriochlorophyll a in Uniformly [13C−15N]-Labeled Light-Harvesting 1 Complexes by Solid-State NMR in Ultrahigh Magnetic Field. J Phys Chem B 2010; 114:6207-15. [DOI: 10.1021/jp100688u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anjali Pandit
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Francesco Buda
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Adriaan J. van Gammeren
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Swapna Ganapathy
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Huub J. M. de Groot
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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50
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Escalante M, Lenferink A, Zhao Y, Tas N, Huskens J, Hunter CN, Subramaniam V, Otto C. Long-range energy propagation in nanometer arrays of light harvesting antenna complexes. NANO LETTERS 2010; 10:1450-1457. [PMID: 20232894 DOI: 10.1021/nl1003569] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Here we report the first observation of long-range transport of excitation energy within a biomimetic molecular nanoarray constructed from LH2 antenna complexes from Rhodobacter sphaeroides. Fluorescence microscopy of the emission of light after local excitation with a diffraction-limited light beam reveals long-range transport of excitation energy over micrometer distances, which is much larger than required in the parent bacterial system. The transport was established from the influence of active energy-guiding layers on the observed fluorescence emission. We speculate that such an extent of energy migration occurs as a result of efficient coupling between many hundreds of LH2 molecules. These results demonstrate the potential for long-range energy propagation in hybrid systems composed of natural light harvesting antenna molecules from photosynthetic organisms.
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Affiliation(s)
- Maryana Escalante
- Nanobiophysics, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
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