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Bin T, Venturoli G, Ghelli AM, Francia F. Use of bacterial photosynthetic vesicles to evaluate the effect of ionic liquids on the permeability of biological membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184291. [PMID: 38296218 DOI: 10.1016/j.bbamem.2024.184291] [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: 10/12/2023] [Revised: 01/22/2024] [Accepted: 01/24/2024] [Indexed: 02/09/2024]
Abstract
Ionic liquids (ILs) are salts composed of a combination of organic or inorganic cations and anions characterized by a low melting point, often below 100 °C. This property, together with an extremely low vapor pressure, low flammability and high thermal stability, makes them suitable for replacing canonical organic solvents, with a reduction of industrial activities impact on the environment. Although in the last decades the eco-compatibility of ILs has been extensively verified through toxicological tests performed on model organisms, a detailed understanding of the interaction of these compounds with biological membranes is far from being exhaustive. In this context, we have chosen to evaluate the effect of some ILs on native membranes by using chromatophores, photosynthetic vesicles that can be isolated from Rhodobacter capsulatus, a member of the purple non‑sulfur bacteria. Here, carotenoids associated with the light-harvesting complex II, act as endogenous spectral probes of the transmembrane electrical potential (ΔΨ). By measuring through time-resolved absorption spectroscopy the evolution of the carotenoid band shift induced by a single excitation of the photosynthetic reaction center, information on the ΔΨ dissipation due to ionic currents across the membrane can be obtained. We found that some ILs cause a rather fast dissipation of the transmembrane ΔΨ even at low concentrations, and that this behavior is dose-dependent. By using two different models to analyze the decay of the carotenoid signals, we attempted to interpret at a mechanistic level the marked increase of ionic permeability caused by specific ILs.
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Affiliation(s)
- Tancredi Bin
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy
| | - Giovanni Venturoli
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy; Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), c/o Dipartimento di Fisica e Astronomia (DIFA), via Irnerio 46, Università di Bologna, I-40126 Bologna, Italy
| | - Anna Maria Ghelli
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy
| | - Francesco Francia
- Department of Pharmacy and Biotechnology, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
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2
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Satoh I, Gotou K, Nagatsuma S, Nagashima KVP, Kobayashi M, Yu LJ, Madigan MT, Kimura Y, Wang-Otomo ZY. Selective expression of light-harvesting complexes alters phospholipid composition in the intracytoplasmic membrane and core complex of purple phototrophic bacteria. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:149001. [PMID: 37527691 DOI: 10.1016/j.bbabio.2023.149001] [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: 04/27/2023] [Revised: 07/23/2023] [Accepted: 07/26/2023] [Indexed: 08/03/2023]
Abstract
Phospholipid-protein interactions play important roles in regulating the function and morphology of photosynthetic membranes in purple phototrophic bacteria. Here, we characterize the phospholipid composition of intracytoplasmic membrane (ICM) from Rhodobacter (Rba.) sphaeroides that has been genetically altered to selectively express light-harvesting (LH) complexes. In the mutant strain (DP2) that lacks a peripheral light-harvesting (LH2) complex, the phospholipid composition was significantly different from that of the wild-type strain; strain DP2 showed a marked decrease in phosphatidylglycerol (PG) and large increases in cardiolipin (CL) and phosphatidylcholine (PC) indicating preferential interactions between the complexes and specific phospholipids. Substitution of the core light-harvesting (LH1) complex of Rba. sphaeroides strain DP2 with that from the purple sulfur bacterium Thermochromatium tepidum further altered the phospholipid composition, with substantial increases in PG and PE and decreases in CL and PC, indicating that the phospholipids incorporated into the ICM depend on the nature of the LH1 complex expressed. Purified LH1-reaction center core complexes (LH1-RC) from the selectively expressing strains also contained different phospholipid compositions than did core complexes from their corresponding wild-type strains, suggesting different patterns of phospholipid association between the selectively expressed LH1-RC complexes and those purified from native strains. Effects of carotenoids on the phospholipid composition were also investigated using carotenoid-suppressed cells and carotenoid-deficient species. The findings are discussed in relation to ICM morphology and specific LH complex-phospholipid interactions.
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Affiliation(s)
- I Satoh
- Faculty of Science, Ibaraki University, Mito 310-8512, Japan
| | - K Gotou
- Faculty of Science, Ibaraki University, Mito 310-8512, Japan
| | - S Nagatsuma
- Faculty of Science, Ibaraki University, Mito 310-8512, Japan
| | - K V P Nagashima
- Research Institute for Integrated Science, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama, Kanagawa 221-8686, Japan
| | - M Kobayashi
- National Institute of Technology, Ariake College, Omuta, Fukuoka 836-8585, Japan
| | - L-J Yu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - M T Madigan
- School of Biological Sciences, Department of Microbiology, Southern Illinois University, Carbondale, IL 62901, USA
| | - Y Kimura
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Nada, Kobe 657-8501, Japan
| | - Z-Y Wang-Otomo
- Faculty of Science, Ibaraki University, Mito 310-8512, Japan.
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3
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Ramos-Martín F, D'Amelio N. Biomembrane lipids: When physics and chemistry join to shape biological activity. Biochimie 2022; 203:118-138. [PMID: 35926681 DOI: 10.1016/j.biochi.2022.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/13/2022] [Accepted: 07/21/2022] [Indexed: 11/02/2022]
Abstract
Biomembranes constitute the first lines of defense of cells. While small molecules can often permeate cell walls in bacteria and plants, they are generally unable to penetrate the barrier constituted by the double layer of phospholipids, unless specific receptors or channels are present. Antimicrobial or cell-penetrating peptides are in fact highly specialized molecules able to bypass this barrier and even discriminate among different cell types. This capacity is made possible by the intrinsic properties of its phospholipids, their distribution between the internal and external leaflet, and their ability to mutually interact, modulating the membrane fluidity and the exposition of key headgroups. Although common phospholipids can be found in the membranes of most organisms, some are characteristic of specific cell types. Here, we review the properties of the most common lipids and describe how they interact with each other in biomembrane. We then discuss how their assembly in bilayers determines some key physical-chemical properties such as permeability, potential and phase status. Finally, we describe how the exposition of specific phospholipids determines the recognition of cell types by membrane-targeting molecules.
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Affiliation(s)
- Francisco Ramos-Martín
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, Amiens, 80039, France.
| | - Nicola D'Amelio
- Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, Amiens, 80039, France.
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4
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Fufina TY, Vasilieva LG. Effect of Detergents and Osmolytes on Thermal Stability of Native and Mutant Rhodobacter sphaeroides Reaction Centers. BIOCHEMISTRY (MOSCOW) 2021; 86:517-524. [PMID: 33941072 DOI: 10.1134/s000629792104012x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Photosynthetic reaction center (RC) of the purple bacterium Rhodobacter sphaeroides is one of the most well-studied transmembrane pigment-protein complexes. It is a relatively stable protein with established conditions for its isolation from membranes, purification, and storage. However, it has been shown that some amino acid substitutions can affect stability of the RC, which results in a decrease of the RCs yield during its isolation and purification, disturbs spectral properties of the RCs during storage, and can lead to sample heterogeneity. To optimize conditions for studying mutant RCs, the effect of various detergents and osmolytes on thermal stability of the complex was examined. It was shown that trehalose and, to a lesser extent, sucrose, maltose, and hydroxyectoin at 1 M concentration slow down thermal denaturation of RCs. Sodium cholate was found to have significant stabilizing effect on the structure of native and genetically modified RCs. The use of sodium cholate as a detergent has several advantages and can be recommended for the storage and investigation of the unstable mutant membrane complexes of purple bacteria in long-term experiments.
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Affiliation(s)
- Tatiana Yu Fufina
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - Lyudmila G Vasilieva
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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5
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Nagatsuma S, Gotou K, Yamashita T, Yu LJ, Shen JR, Madigan M, Kimura Y, Wang-Otomo ZY. Phospholipid distributions in purple phototrophic bacteria and LH1-RC core complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:461-468. [DOI: 10.1016/j.bbabio.2019.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/06/2019] [Accepted: 04/07/2019] [Indexed: 02/06/2023]
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6
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Photosynthetic apparatus of Rhodobacter sphaeroides exhibits prolonged charge storage. Nat Commun 2019; 10:902. [PMID: 30796237 PMCID: PMC6385238 DOI: 10.1038/s41467-019-08817-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 01/25/2019] [Indexed: 12/17/2022] Open
Abstract
Photosynthetic proteins have been extensively researched for solar energy harvesting. Though the light-harvesting and charge-separation functions of these proteins have been studied in depth, their potential as charge storage systems has not been investigated to the best of our knowledge. Here, we report prolonged storage of electrical charge in multilayers of photoproteins isolated from Rhodobacter sphaeroides. Direct evidence for charge build-up within protein multilayers upon photoexcitation and external injection is obtained by Kelvin-probe and scanning-capacitance microscopies. Use of these proteins is key to realizing a 'self-charging biophotonic device' that not only harvests light and photo-generates charges but also stores them. In strong correlation with the microscopic evidence, the phenomenon of prolonged charge storage is also observed in primitive power cells constructed from the purple bacterial photoproteins. The proof-of-concept power cells generated a photovoltage as high as 0.45 V, and stored charge effectively for tens of minutes with a capacitance ranging from 0.1 to 0.2 F m-2.
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7
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Liu J, Friebe V, Swainsbury DJK, Crouch LI, Szabo DA, Frese RN, Jones MR. Engineered photoproteins that give rise to photosynthetically-incompetent bacteria are effective as photovoltaic materials for biohybrid photoelectrochemical cells. Faraday Discuss 2018; 207:307-327. [PMID: 29364305 PMCID: PMC5903125 DOI: 10.1039/c7fd00190h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 09/04/2017] [Indexed: 01/27/2023]
Abstract
Reaction centre/light harvesting proteins such as the RCLH1X complex from Rhodobacter sphaeroides carry out highly quantum-efficient conversion of solar energy through ultrafast energy transfer and charge separation, and these pigment-proteins have been incorporated into biohybrid photoelectrochemical cells for a variety of applications. In this work we demonstrate that, despite not being able to support normal photosynthetic growth of Rhodobacter sphaeroides, an engineered variant of this RCLH1X complex lacking the PufX protein and with an enlarged light harvesting antenna is unimpaired in its capacity for photocurrent generation in two types of bio-photoelectrochemical cells. Removal of PufX also did not impair the ability of the RCLH1 complex to act as an acceptor of energy from synthetic light harvesting quantum dots. Unexpectedly, the removal of PufX led to a marked improvement in the overall stability of the RCLH1 complex under heat stress. We conclude that PufX-deficient RCLH1 complexes are fully functional in solar energy conversion in a device setting and that their enhanced structural stability could make them a preferred choice over their native PufX-containing counterpart. Our findings on the competence of RCLH1 complexes for light energy conversion in vitro are discussed with reference to the reason why these PufX-deficient proteins are not capable of light energy conversion in vivo.
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Affiliation(s)
- Juntai Liu
- School of Biochemistry , University of Bristol , Medical Sciences Building, University Walk , Bristol BS8 1TD , UK .
| | - Vincent M. Friebe
- Department of Physics and Astronomy , LaserLaB Amsterdam , VU University Amsterdam , De Boelelaan 1081, 1081 HV , Amsterdam , The Netherlands
| | - David J. K. Swainsbury
- School of Biochemistry , University of Bristol , Medical Sciences Building, University Walk , Bristol BS8 1TD , UK .
| | - Lucy I. Crouch
- School of Biochemistry , University of Bristol , Medical Sciences Building, University Walk , Bristol BS8 1TD , UK .
| | - David A. Szabo
- School of Biochemistry , University of Bristol , Medical Sciences Building, University Walk , Bristol BS8 1TD , UK .
| | - Raoul N. Frese
- Department of Physics and Astronomy , LaserLaB Amsterdam , VU University Amsterdam , De Boelelaan 1081, 1081 HV , Amsterdam , The Netherlands
| | - Michael R. Jones
- School of Biochemistry , University of Bristol , Medical Sciences Building, University Walk , Bristol BS8 1TD , UK .
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8
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Noji T, Matsuo M, Takeda N, Sumino A, Kondo M, Nango M, Itoh S, Dewa T. Lipid-Controlled Stabilization of Charge-Separated States (P+QB–) and Photocurrent Generation Activity of a Light-Harvesting–Reaction Center Core Complex (LH1-RC) from Rhodopseudomonas palustris. J Phys Chem B 2018; 122:1066-1080. [DOI: 10.1021/acs.jpcb.7b09973] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Tomoyasu Noji
- The OCU Advanced Research Institute for Natural Science & Technology (OCARINA), Osaka City University, Sugimoto-cho, Sumiyoshi-ku, Osaka 558−8585, Japan
| | - Mikano Matsuo
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Nobutaka Takeda
- Department
of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Ayumi Sumino
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 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 466-8555, Japan
| | - Mamoru Nango
- The OCU Advanced Research Institute for Natural Science & Technology (OCARINA), Osaka City University, Sugimoto-cho, Sumiyoshi-ku, Osaka 558−8585, Japan
| | - Shigeru Itoh
- Division
of Material Sciences (Physics), Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464−8602, Japan
| | - Takehisa Dewa
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
- Department
of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
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9
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Swainsbury DJK, Proctor MS, Hitchcock A, Cartron ML, Qian P, Martin EC, Jackson PJ, Madsen J, Armes SP, Hunter CN. Probing the local lipid environment of the Rhodobacter sphaeroides cytochrome bc 1 and Synechocystis sp. PCC 6803 cytochrome b 6f complexes with styrene maleic acid. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1859:215-225. [PMID: 29291373 PMCID: PMC5805856 DOI: 10.1016/j.bbabio.2017.12.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/21/2017] [Accepted: 12/28/2017] [Indexed: 01/21/2023]
Abstract
Intracytoplasmic vesicles (chromatophores) in the photosynthetic bacterium Rhodobacter sphaeroides represent a minimal structural and functional unit for absorbing photons and utilising their energy for the generation of ATP. The cytochrome bc1 complex (cytbc1) is one of the four major components of the chromatophore alongside the reaction centre-light harvesting 1-PufX core complex (RC-LH1-PufX), the light-harvesting 2 complex (LH2), and ATP synthase. Although the membrane organisation of these complexes is known, their local lipid environments have not been investigated. Here we utilise poly(styrene-alt-maleic acid) (SMA) co-polymers as a tool to simultaneously determine the local lipid environments of the RC-LH1-PufX, LH2 and cytbc1 complexes. SMA has previously been reported to effectively solubilise complexes in lipid-rich membrane regions whilst leaving lipid-poor ordered protein arrays intact. Here we show that SMA solubilises cytbc1 complexes with an efficiency of nearly 70%, whereas solubilisation of RC-LH1-PufX and LH2 was only 10% and 22% respectively. This high susceptibility of cytbc1 to SMA solubilisation is consistent with this complex residing in a locally lipid-rich region. SMA solubilised cytbc1 complexes retain their native dimeric structure and co-purify with 56 ± 6 phospholipids from the chromatophore membrane. We extended this approach to the model cyanobacterium Synechocystis sp. PCC 6803, and show that the cytochrome b6f complex (cytb6f) and Photosystem II (PSII) complexes are susceptible to SMA solubilisation, suggesting they also reside in lipid-rich environments. Thus, lipid-rich membrane regions could be a general requirement for cytbc1/cytb6f complexes, providing a favourable local solvent to promote rapid quinol/quinone binding and release at the Q0 and Qi sites. SMA preferentially solubilises cytbc1 from chromatophore membranes. Solubilised cytbc1 SMALPs contain dimeric complexes co-purified with 56 lipids. SMA-resistant fractions contain RC-LH1-PufX and LH2 rich membrane patches. The Rba. sphaeroides cytbc1 complex is likely to reside in a lipid-rich environment. Similar results for Synechocystis suggest cytbc1/b6f may be universally lipid-rich.
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Affiliation(s)
- David J K Swainsbury
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Matthew S Proctor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Michaël L Cartron
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Pu Qian
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Elizabeth C Martin
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Philip J Jackson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom; ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Jeppe Madsen
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - Steven P Armes
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom.
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10
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Kimura Y, Kawakami T, Yu LJ, Yoshimura M, Kobayashi M, Wang-Otomo ZY. Characterization of the quinones in purple sulfur bacteriumThermochromatium tepidum. FEBS Lett 2015; 589:1761-5. [DOI: 10.1016/j.febslet.2015.05.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 05/21/2015] [Accepted: 05/22/2015] [Indexed: 11/27/2022]
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11
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Luévano-Martínez LA, Forni MF, dos Santos VT, Souza-Pinto NC, Kowaltowski AJ. Cardiolipin is a key determinant for mtDNA stability and segregation during mitochondrial stress. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:587-98. [PMID: 25843549 DOI: 10.1016/j.bbabio.2015.03.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 03/16/2015] [Accepted: 03/29/2015] [Indexed: 01/05/2023]
Abstract
Mitochondria play a key role in adaptation during stressing situations. Cardiolipin, the main anionic phospholipid in mitochondrial membranes, is expected to be a determinant in this adaptive mechanism since it modulates the activity of most membrane proteins. Here, we used Saccharomyces cerevisiae subjected to conditions that affect mitochondrial metabolism as a model to determine the possible role of cardiolipin in stress adaptation. Interestingly, we found that thermal stress promotes a 30% increase in the cardiolipin content and modifies the physical state of mitochondrial membranes. These changes have effects on mtDNA stability, adapting cells to thermal stress. Conversely, this effect is cardiolipin-dependent since a cardiolipin synthase-null mutant strain is unable to adapt to thermal stress as observed by a 60% increase of cells lacking mtDNA (ρ0). Interestingly, we found that the loss of cardiolipin specifically affects the segregation of mtDNA to daughter cells, leading to a respiratory deficient phenotype after replication. We also provide evidence that mtDNA physically interacts with cardiolipin both in S. cerevisiae and in mammalian mitochondria. Overall, our results demonstrate that the mitochondrial lipid cardiolipin is a key determinant in the maintenance of mtDNA stability and segregation.
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Affiliation(s)
- Luis Alberto Luévano-Martínez
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Cidade Universitária, Av. Prof. Lineu Prestes, 748, São Paulo, SP 05508-000, Brazil.
| | - Maria Fernanda Forni
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Cidade Universitária, Av. Prof. Lineu Prestes, 748, São Paulo, SP 05508-000, Brazil
| | - Valquiria Tiago dos Santos
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Cidade Universitária, Av. Prof. Lineu Prestes, 748, São Paulo, SP 05508-000, Brazil
| | - Nadja C Souza-Pinto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Cidade Universitária, Av. Prof. Lineu Prestes, 748, São Paulo, SP 05508-000, Brazil
| | - Alicia J Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Cidade Universitária, Av. Prof. Lineu Prestes, 748, São Paulo, SP 05508-000, Brazil
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12
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Cartron ML, Olsen JD, Sener M, Jackson PJ, Brindley AA, Qian P, Dickman MJ, Leggett GJ, Schulten K, Neil Hunter C. Integration of energy and electron transfer processes in the photosynthetic membrane of Rhodobacter sphaeroides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1769-80. [PMID: 24530865 DOI: 10.1016/j.bbabio.2014.02.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 02/03/2014] [Accepted: 02/05/2014] [Indexed: 02/04/2023]
Abstract
Photosynthesis converts absorbed solar energy to a protonmotive force, which drives ATP synthesis. The membrane network of chlorophyll-protein complexes responsible for light absorption, photochemistry and quinol (QH2) production has been mapped in the purple phototrophic bacterium Rhodobacter (Rba.) sphaeroides using atomic force microscopy (AFM), but the membrane location of the cytochrome bc1 (cytbc1) complexes that oxidise QH2 to quinone (Q) to generate a protonmotive force is unknown. We labelled cytbc1 complexes with gold nanobeads, each attached by a Histidine10 (His10)-tag to the C-terminus of cytc1. Electron microscopy (EM) of negatively stained chromatophore vesicles showed that the majority of the cytbc1 complexes occur as dimers in the membrane. The cytbc1 complexes appeared to be adjacent to reaction centre light-harvesting 1-PufX (RC-LH1-PufX) complexes, consistent with AFM topographs of a gold-labelled membrane. His-tagged cytbc1 complexes were retrieved from chromatophores partially solubilised by detergent; RC-LH1-PufX complexes tended to co-purify with cytbc1 whereas LH2 complexes became detached, consistent with clusters of cytbc1 complexes close to RC-LH1-PufX arrays, but not with a fixed, stoichiometric cytbc1-RC-LH1-PufX supercomplex. This information was combined with a quantitative mass spectrometry (MS) analysis of the RC, cytbc1, ATP synthase, cytaa3 and cytcbb3 membrane protein complexes, to construct an atomic-level model of a chromatophore vesicle comprising 67 LH2 complexes, 11 LH1-RC-PufX dimers & 2 RC-LH1-PufX monomers, 4 cytbc1 dimers and 2 ATP synthases. Simulation of the interconnected energy, electron and proton transfer processes showed a half-maximal ATP turnover rate for a light intensity equivalent to only 1% of bright sunlight. Thus, the photosystem architecture of the chromatophore is optimised for growth at low light intensities.
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Affiliation(s)
- Michaël L Cartron
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - John D Olsen
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Melih Sener
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Philip J Jackson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK; ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
| | - Amanda A Brindley
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Pu Qian
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Mark J Dickman
- ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
| | - Graham J Leggett
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - Klaus Schulten
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
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13
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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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14
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Jakob-Grun S, Radeck J, Braun P. Ca(2+)-binding reduces conformational flexibility of RC-LH1 core complex from thermophile Thermochromatium tepidum. PHOTOSYNTHESIS RESEARCH 2012; 111:139-147. [PMID: 22367594 DOI: 10.1007/s11120-012-9727-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 02/09/2012] [Indexed: 05/31/2023]
Abstract
The light-harvesting complex, LH1, of thermophile purple bacteria Thermochromatium tepidum consists of an array of α- and β-polypeptides which assemble the photoactive bacteriochlorophyll and closely interact with the membrane-lipids. In this study, we investigated the effect of calcium and manganese ions on the protein structure and thermostability of the reaction centre (RC)-LH1/lipid complex. The binding of Ca(2+), but not Mn(2+) is shown to shift the LH1 Q ( y ) absorption maximum from ~889 to 915 nm and to significantly raise the thermostability of the RC-LH1 complex. The ATR-FTIR spectra indicate that interaction of Ca(2+) as monitored by the carboxylates' vibration of aspartate residues, but not Mn(2+) induces changes in the α-helix packing arrangement. The reduced rate of (1)H/(2)H exchange of proteins' amide protons shows that the accessibility to (2)H(2)O is significantly lowered in Ca(2+)-substituted RC-LH1/lipid complexes. In particular, exchange with the associated lipid molecules, is significantly retarded. These results suggest that the thermostability of the RC-LH1 complex is raised by the distinct interaction with calcium cations which reduces the RC-LH1/lipid dynamics, particularly, at the membrane-water interface.
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Affiliation(s)
- Selma Jakob-Grun
- Department Biology I, Botany, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany
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15
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Stahl AD, Crouch LI, Jones MR, van Stokkum I, van Grondelle R, Groot ML. Role of PufX in Photochemical Charge Separation in the RC-LH1 Complex from Rhodobacter sphaeroides: An Ultrafast Mid-IR Pump–Probe Investigation. J Phys Chem B 2011; 116:434-44. [DOI: 10.1021/jp206697k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Andreas D. Stahl
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Lucy I. Crouch
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Michael R. Jones
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Ivo van Stokkum
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Marie Louise Groot
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
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16
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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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17
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Export or recombination of charges in reaction centers in intact cells of photosynthetic bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1444-50. [DOI: 10.1016/j.bbabio.2009.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 06/09/2009] [Accepted: 06/10/2009] [Indexed: 11/24/2022]
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18
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Kors CA, Wallace E, Davies DR, Li L, Laible PD, Nollert P. Effects of impurities on membrane-protein crystallization in different systems. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2009; 65:1062-73. [PMID: 19770503 PMCID: PMC2748966 DOI: 10.1107/s0907444909029163] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 07/22/2009] [Indexed: 11/18/2022]
Abstract
When starting a protein-crystallization project, scientists are faced with several unknowns. Amongst them are these questions: (i) is the purity of the starting material sufficient? and (ii) which type of crystallization experiment is the most promising to conduct? The difficulty in purifying active membrane-protein samples for crystallization trials and the high costs associated with producing such samples require an extremely pragmatic approach. Additionally, practical guidelines are needed to increase the efficiency of membrane-protein crystallization. In order to address these conundrums, the effects of commonly encountered impurities on various membrane-protein crystallization regimes have been investigated and it was found that the lipidic cubic phase (LCP) based crystallization methodology is more robust than crystallization in detergent environments using vapor diffusion or microbatch approaches in its ability to tolerate contamination in the forms of protein, lipid or other general membrane components. LCP-based crystallizations produced crystals of the photosynthetic reaction center (RC) of Rhodobacter sphaeroides from samples with substantial levels of residual impurities. Crystals were obtained with protein contamination levels of up to 50% and the addition of lipid material and membrane fragments to pure samples of RC had little effect on the number or on the quality of crystals obtained in LCP-based crystallization screens. If generally applicable, this tolerance for impurities may avoid the need for samples of ultrahigh purity when undertaking initial crystallization screening trials to determine preliminary crystallization conditions that can be optimized for a given target protein.
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Affiliation(s)
- Christopher A. Kors
- Biosciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
| | - Ellen Wallace
- deCODE biostructures, 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
| | - Douglas R. Davies
- deCODE biostructures, 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
| | - Liang Li
- Department of Chemistry and Institute for Biophysical Dynamics, University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
| | - Philip D. Laible
- Biosciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
| | - Peter Nollert
- deCODE biostructures, 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
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19
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Sturgis JN, Tucker JD, Olsen JD, Hunter CN, Niederman RA. Atomic Force Microscopy Studies of Native Photosynthetic Membranes. Biochemistry 2009; 48:3679-98. [DOI: 10.1021/bi900045x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James N. Sturgis
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, UPR 9027, Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseilles, France, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K., and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854-8082
| | - Jaimey D. Tucker
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, UPR 9027, Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseilles, France, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K., and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854-8082
| | - John D. Olsen
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, UPR 9027, Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseilles, France, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K., and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854-8082
| | - C. Neil Hunter
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, UPR 9027, Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseilles, France, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K., and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854-8082
| | - Robert A. Niederman
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, UPR 9027, Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseilles, France, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K., and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854-8082
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20
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Kern J, Zouni A, Guskov A, Krauß N. Lipids in the Structure of Photosystem I, Photosystem II and the Cytochrome b 6 f Complex. LIPIDS IN PHOTOSYNTHESIS 2009. [DOI: 10.1007/978-90-481-2863-1_10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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21
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22
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The redox midpoint potential of the primary quinone of reaction centers in chromatophores of Rhodobacter sphaeroides is pH independent. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 37:1207-17. [DOI: 10.1007/s00249-008-0301-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 02/11/2008] [Accepted: 03/02/2008] [Indexed: 10/22/2022]
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23
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Qian P, Bullough PA, Hunter CN. Three-dimensional reconstruction of a membrane-bending complex: the RC-LH1-PufX core dimer of Rhodobacter sphaeroides. J Biol Chem 2008; 283:14002-11. [PMID: 18326046 DOI: 10.1074/jbc.m800625200] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A three-dimensional model of the dimeric reaction center-light harvesting I-PufX (RC-LH1-PufX) complex from Rhodobacter sphaeroides, calculated from electron microscope single particle analysis of negatively stained complexes, shows that the two halves of the dimer molecule incline toward each other on the periplasmic side, creating a remarkable V-shaped structure. The distribution of negative stain is consistent with loose packing of the LH1 ring near the 14th LH1 alpha/beta pair, which could facilitate the migration of quinone and quinol molecules across the LH1 boundary. The three-dimensional model encloses a space near the reaction center Q(B) site and the 14th LH1 alpha/beta pair, which is approximately 20 angstroms in diameter, sufficient to sequester a quinone pool. Helical arrays of dimers were used to construct a three-dimensional membrane model, which matches the packing lattice deduced from electron microscope analysis of the tubular dimer-only membranes found in mutants of Rba. sphaeroides lacking the LH2 complex. The intrinsic curvature of the dimer explains the shape and approximately 70-nm diameter of these membrane tubules, and at least partially accounts for the spherical membrane invaginations found in wild-type Rba. sphaeroides. A model of dimer aggregation and membrane curvature in these spherical membrane invaginations is presented.
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Affiliation(s)
- Pu Qian
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
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