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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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2
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Yoneda Y, Noji T, Mizutani N, Kato D, Kondo M, Miyasaka H, Nagasawa Y, Dewa T. Energy transfer dynamics and the mechanism of biohybrid photosynthetic antenna complexes chemically linked with artificial chromophores. Phys Chem Chem Phys 2022; 24:24714-24726. [PMID: 36128743 DOI: 10.1039/d2cp02465a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A light-harvesting strategy is crucial for the utilisation of solar energy. In this study, we addressed the expanding light-harvesting (LH) wavelength of photosynthetic LH complex 2 (LH2, from Rhodoblastus acidophilus strain 10050) through covalent conjugation with extrinsic chromophores. To further understand the conjugation architecture and mechanism of excitation energy transfer (EET), we examined the effects of the linker length and spectral overlap integral between the emission and absorption spectra of the energy donor and acceptor pigments. In the former case, contrary to the intuition based on the Förster resonance energy transfer (FRET) theory, the observed energy transfer rate was similar regardless of the linker length, and the energy transfer efficiency increased with longer linkers. In the latter case, despite the energy transfer rate increases at higher spectral overlaps, it was quantitatively inconsistent with the FRET theory. The mechanism of EET beyond the FRET theory was discussed in terms of the higher-lying exciton state of B850, which mediates efficient EET despite the small spectral overlap. This systematic investigation provides insights for the development of efficient artificial photosynthetic systems.
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Affiliation(s)
- Yusuke Yoneda
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.,Research Center of Integrative Molecular Systems, Institute for Molecular Science, National Institute of Natural Sciences, Okazaki, Aichi, 444-8585, Japan.
| | - Tomoyasu Noji
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan.
| | - Naoto Mizutani
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan.
| | - Daiji Kato
- 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.
| | - Hiroshi Miyasaka
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Yutaka Nagasawa
- College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
| | - 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.
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3
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Yoneda Y, Kito M, Mori D, Goto A, Kondo M, Miyasaka H, Nagasawa Y, Dewa T. Ultrafast Energy Transfer between Self-Assembled Fluorophore and Photosynthetic Light-Harvesting Complex 2 (LH2) in Lipid Bilayer. J Chem Phys 2022; 156:095101. [DOI: 10.1063/5.0077910] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | | | | | | | - Masaharu Kondo
- Life Science and Applied Chemistry, Nagoya Institute of Technology, Japan
| | - Hiroshi Miyasaka
- Frontier Materials Science, Osaka University Graduate School of Engineering Science School of Engineering Science, Japan
| | - Yutaka Nagasawa
- College of Lifesciences, Ritsumeikan University College of Life Sciences Graduate School of Life Sciences, Japan
| | - Takehisa Dewa
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Japan
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4
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Rama Krishna VS, Adak S, Jana P, Bheemireddy V, Bandyopadhyay S. Mimicking the Energy Funnel of the Photosynthetic Unit Using a Dendrimer-Dye Supramolecular Assembly. Chem Asian J 2021; 16:3481-3486. [PMID: 34487427 DOI: 10.1002/asia.202100886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/01/2021] [Indexed: 11/10/2022]
Abstract
Photosynthesis involves light-harvesting complexes where an array of antenna pigment channels the absorbed solar energy to the reaction centre of a photosystem. This work reports a supramolecular dendrimer-dye assembly that mimics the natural light-harvesting mechanism. A dendrimeric molecule based on two-fluorophores has been constructed with three coumarin units at the end of three long arms and a 7-diethylaminocoumarin unit at the interior. The molecule self-aggregates in water into spherical micelles, which can encapsulate a rose-bengal dye (RB). On excitation, peripheral coumarin units shuttled the energy to the loaded RB dye reaction center via a two-step cascade resonance energy transfer (RET). The energy absorbed in the periphery is funnelled efficiently, resulting in a strong emission from the dye that resembles an energy funnel. The energy transfer cascade has been studied with both steady-state and time-resolved fluorescence spectroscopy. Molecular dynamics simulations of the self-assembled aggregates in water were also in agreement with the experimental observations.
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Affiliation(s)
- V Siva Rama Krishna
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, West Bengal, India
| | - Soumen Adak
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, West Bengal, India
| | - Palash Jana
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, West Bengal, India
| | - Varun Bheemireddy
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, West Bengal, India
| | - Subhajit Bandyopadhyay
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, West Bengal, India
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5
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Saga Y, Otsuka Y, Tanaka A, Masaoka Y, Hidaka T, Nagasawa Y. Energy Transfer Dynamics in Light-Harvesting Complex 2 Variants Containing Oxidized B800 Bacteriochlorophyll a. J Phys Chem B 2021; 125:6830-6836. [PMID: 34139847 DOI: 10.1021/acs.jpcb.1c01592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Excitation energy transfer (EET) in light-harvesting proteins is vital for photosynthetic activities. The pigment compositions and their organizations in these proteins are responsible for the EET functions. Thus, changing the pigment compositions in light-harvesting proteins contributes to a better understanding of EET mechanisms. In this study, we investigated the EET dynamics of two light-harvesting complex 2 (LH2) variants, in which nine B800 bacteriochlorophyll (BChl) a pigments were entirely or half converted to 3-acetyl chlorophyll (AcChl) a. The AcChl a pigments showed a Qy band, which was blue-shifted by 107 nm from B800 BChl a in the two variants. EET from AcChl a to B850 BChl a was observed in both fully oxidized and half-oxidized LH2 variants, but the EET rates were lower than that from B800 to B850 BChl a. EET from AcChl a to the co-present B800 was barely detected in the half-oxidized LH2. The preferential EET from AcChl a to B850 instead of B800 was rationalized by little spectral overlap of AcChl a with B800 BChl a and the pigment geometry in the protein. The EET rate from B800 to B850 BChl a in the half-oxidized LH2 was analogous to that in native LH2, indicating that partial oxidation of B800 did not disturb the EET channel from the residual B800 to B850.
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Affiliation(s)
- Yoshitaka Saga
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Yuji Otsuka
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Aiko Tanaka
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Yuto Masaoka
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Tsubasa Hidaka
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Yutaka Nagasawa
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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6
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Kasagi G, Yoneda Y, Kondo M, Miyasaka H, Nagasawa Y, Dewa T. Enhanced light harvesting and photocurrent generation activities of biohybrid light–harvesting 1–reaction center core complexes (LH1-RCs) from Rhodopseudomonas palustris. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2020.112790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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7
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Huang X, Vasilev C, Hunter CN. Excitation energy transfer between monomolecular layers of light harvesting LH2 and LH1-reaction centre complexes printed on a glass substrate. LAB ON A CHIP 2020; 20:2529-2538. [PMID: 32662473 DOI: 10.1039/d0lc00156b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Light-harvesting 2 (LH2) and light-harvesting 1 - reaction centre (RCLH1) complexes purified from the photosynthetic bacterium Rhodobacter (Rba.) sphaeroides were cross-patterned on glass surfaces for energy transfer studies. Atomic force microscopy (AFM) images of the RCLH1 and LH2 patterns show the deposition of monomolecular layers of complexes on the glass substrate. Spectral imaging and fluorescence life-time imaging microscopy (FLIM) revealed that RCLH1 and LH2 complexes, sealed under physiological conditions, retained their native light-harvesting and energy transfer functions. Measurements of the amplitude and lifetime decay of fluorescence emission from LH2 complexes, the energy transfer donors, and gain of fluorescence emission from acceptor RCLH1 complexes, provide evidence for excitation energy transfer from LH2 to RCLH1. Directional energy transfer on the glass substrate was unequivocally established by using LH2-carotenoid complexes and RCLH1 complexes with genetically removed carotenoids. Specific excitation of carotenoids in donor LH2 complexes elicited fluorescence emission from RCLH1 acceptors. To explore the longevity of this novel nanoprinted photosynthetic unit, RCLH1 and LH2 complexes were cross-patterned on a glass surface and sealed under a protective argon atmosphere. The results show that both complexes retained their individual and collective functions and are capable of directional excitation energy transfer for at least 60 days.
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Affiliation(s)
- Xia Huang
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
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8
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Effects of palladium ions on light-harvesting complex 2 lacking B800 bacteriochlorophyll a. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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9
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Saga Y, Yamashita M, Imanishi M, Kimura Y, Masaoka Y, Hidaka T, Nagasawa Y. Reconstitution of 3-Acetyl Chlorophyll a into Light-Harvesting Complex 2 from the Purple Photosynthetic Bacterium Phaeospirillum molischianum. ACS OMEGA 2020; 5:6817-6825. [PMID: 32258917 PMCID: PMC7114761 DOI: 10.1021/acsomega.0c00152] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 03/06/2020] [Indexed: 06/11/2023]
Abstract
The manipulation of B800 bacteriochlorophyll (BChl) a in light-harvesting complex 2 (LH2) from the purple photosynthetic bacterium Phaeospirillum molischianum (molischianum-LH2) provides insight for understanding the energy transfer mechanism and the binding of cyclic tetrapyrroles in LH2 proteins since molischianum-LH2 is one of the two LH2 proteins whose atomic-resolution structures have been determined and is a representative of type-2 LH2 proteins. However, there is no report on the substitution of B800 BChl a in molischianum-LH2. We report the reconstitution of 3-acetyl chlorophyll (AcChl) a, which has a 17,18-dihydroporphyrin skeleton, to the B800 site in molischianum-LH2. The 3-acetyl group in AcChl a formed a hydrogen bond with β'-Thr23 in essentially the same manner as native B800 BChl a, but this hydrogen bond was weaker than that of B800 BChl a. This change can be rationalized by invoking a small distortion in the orientation of the 3-acetyl group in the B800 cavity by dehydrogenation in the B-ring from BChl a. The energy transfer from AcChl a in the B800 site to B850 BChl a was about 5-fold slower than that from native B800 BChl a by a decrease of the spectral overlap between energy-donating AcChl a and energy-accepting B850 BChl a.
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Affiliation(s)
- Yoshitaka Saga
- Department
of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka 577-8502, Osaka, Japan
| | - Madoka Yamashita
- Department
of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka 577-8502, Osaka, Japan
| | - Michie Imanishi
- Graduate
School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Yukihiro Kimura
- Graduate
School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Yuto Masaoka
- Graduate
School of Life Sciences, Ritsumeikan University, Kusatsu 525-8577, Shiga, Japan
| | - Tsubasa Hidaka
- Graduate
School of Life Sciences, Ritsumeikan University, Kusatsu 525-8577, Shiga, Japan
| | - Yutaka Nagasawa
- Graduate
School of Life Sciences, Ritsumeikan University, Kusatsu 525-8577, Shiga, Japan
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10
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Im SW, Ha H, Yang W, Jang JH, Kang B, Seo DH, Seo J, Nam KT. Light polarization dependency existing in the biological photosystem and possible implications for artificial antenna systems. PHOTOSYNTHESIS RESEARCH 2020; 143:205-220. [PMID: 31643017 DOI: 10.1007/s11120-019-00682-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/02/2019] [Indexed: 06/10/2023]
Abstract
The processes of biological photosynthesis provide inspiration and valuable lessons for artificial energy collection, transfer, and conversion systems. The extraordinary efficiency of each sequential process of light to biomass conversion originates from the unique architecture and mechanism of photosynthetic proteins. Near 100% quantum efficiency of energy transfer in biological photosystems is achieved by the chlorophyll assemblies in antenna complexes, which also exhibit a significant degree of light polarization. The three-dimensional chiral assembly of chlorophylls is an optimized biological architecture that enables maximum energy transfer efficiency with precisely designed coupling between chlorophylls. In this review, we summarize the key lessons from the photosynthetic processes in biological photosystems, and move our focus to energy transfer mechanisms and the chiral structure of the chlorophyll assembly. Then, we introduce recent approaches and possible implications to realize the biological energy transfer processes on bioinspired scaffold-based artificial antenna systems.
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Affiliation(s)
- Sang Won Im
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Heonjin Ha
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Woojin Yang
- Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Jun Ho Jang
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Boyeong Kang
- Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Da Hye Seo
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Jiwon Seo
- Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea.
| | - Ki Tae Nam
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea.
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11
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Yoneda Y, Kato D, Kondo M, Nagashima KVP, Miyasaka H, Nagasawa Y, Dewa T. Sequential energy transfer driven by monoexponential dynamics in a biohybrid light-harvesting complex 2 (LH2). PHOTOSYNTHESIS RESEARCH 2020; 143:115-128. [PMID: 31620983 DOI: 10.1007/s11120-019-00677-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Enhancing the light-harvesting potential of antenna components in a system of solar energy conversion is an important topic in the field of artificial photosynthesis. We constructed a biohybrid light-harvesting complex 2 (LH2) engineered from Rhodobacter sphaeroides IL106 strain. An artificial fluorophore Alexa Fluor 647 maleimide (A647) was attached to the LH2 bearing cysteine residue at the N-terminal region (LH2-NC) near B800 bacteriochlorophyll a (BChl) assembly. The A647-attached LH2-NC conjugate (LH2-NC-A647) preserved the integrity of the intrinsic chromophores, B800- and B850-BChls, and carotenoids. Femtosecond transient absorption spectroscopy revealed that the sequential energy transfer A647 → B800 → B850 occurs at time scale of 9-10 ps with monoexponential dynamics in micellar and lipid bilayer systems. A B800-removed conjugate (LH2-NC[B800(-)]-A647) exhibited a significant decrease in energy transfer efficiency in the micellar system; however, surprisingly, direct energy transfer from A647 to B850 was observed at a rate comparable to that for LH2-NC-A647. This result implies that the energy transfer pathway is modified after B800 removal. The results obtained suggested that a LH2 complex is a potential platform for construction of biohybrid light-harvesting materials with simple energy transfer dynamics through the site-selective attachment of the external antennae and the modifiable energy-funnelling pathway.
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Affiliation(s)
- Yusuke Yoneda
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, 560-8531, Japan
| | - Daiji Kato
- 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
| | - Kenji V P Nagashima
- Research Institute for Integrated Science, Kanagawa University, Kanagawa, 259-1293, Japan
| | - Hiroshi Miyasaka
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, 560-8531, Japan
| | - Yutaka Nagasawa
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan.
| | - 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.
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12
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Engineering of B800 bacteriochlorophyll binding site specificity in the Rhodobacter sphaeroides LH2 antenna. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:209-223. [PMID: 30414933 PMCID: PMC6358721 DOI: 10.1016/j.bbabio.2018.11.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/19/2018] [Accepted: 11/07/2018] [Indexed: 11/22/2022]
Abstract
The light-harvesting 2 complex (LH2) of the purple phototrophic bacterium Rhodobacter sphaeroides is a highly efficient, light-harvesting antenna that allows growth under a wide-range of light intensities. In order to expand the spectral range of this antenna complex, we first used a series of competition assays to measure the capacity of the non-native pigments 3-acetyl chlorophyll (Chl) a, Chl d, Chl f or bacteriochlorophyll (BChl) b to replace native BChl a in the B800 binding site of LH2. We then adjusted the B800 site and systematically assessed the binding of non-native pigments. We find that Arg-10 of the LH2 β polypeptide plays a crucial role in binding specificity, by providing a hydrogen-bond to the 3-acetyl group of native and non-native pigments. Reconstituted LH2 complexes harbouring the series of (B)Chls were examined by transient absorption and steady-state fluorescence spectroscopies. Although slowed 10-fold to ~6 ps, energy transfer from Chl a to B850 BChl a remained highly efficient. We measured faster energy-transfer time constants for Chl d (3.5 ps) and Chl f (2.7 ps), which have red-shifted absorption maxima compared to Chl a. BChl b, red-shifted from the native BChl a, gave extremely rapid (≤0.1 ps) transfer. These results show that modified LH2 complexes, combined with engineered (B)Chl biosynthesis pathways in vivo, have potential for retaining high efficiency whilst acquiring increased spectral range.
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13
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Noble JM, Lubieniecki J, Savitzky BH, Plitzko J, Engelhardt H, Baumeister W, Kourkoutis LF. Connectivity of centermost chromatophores in Rhodobacter sphaeroides bacteria. Mol Microbiol 2018; 109:812-825. [PMID: 29995992 DOI: 10.1111/mmi.14077] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 07/05/2018] [Accepted: 07/12/2018] [Indexed: 01/20/2023]
Abstract
The size of whole Rhodobacter sphaeroides prevents 3D visualization of centermost chromatophores in their native environment. This study combines cryo-focused ion beam milling with cryo-electron tomography to probe vesicle architecture both in situ and in 3D. Developing chromatophores are membrane-bound buds that remain in topological continuity with the cytoplasmic membrane and detach into vesicles when mature. Mature chromatophores closest to the cell wall are typically isolated vesicles, whereas centermost chromatophores are either linked to neighboring chromatophores or contain smaller, budding structures. Isolated chromatophores comprised a minority of centermost chromatophores. Connections between vesicles in growing bacteria are through ~10 nm-long, ~5 nm-wide linkers, and are thus physical rather than functional in terms of converting photons to ATP. In cells in the stationary phase, chromatophores fuse with neighboring vesicles, lose their spherical structure, and greatly increase in volume. The fusion and morphological changes seen in older bacteria are likely a consequence of the aging process, and are not representative of connectivity in healthy R. sphaeroides. Our results suggest that chromatophores can adopt either isolated or connected morphologies within a single bacterium. Revealing the organization of chromatophore vesicles throughout the cell is an important step in understanding the photosynthetic mechanisms in R. sphaeroides.
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Affiliation(s)
- Jade M Noble
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA
| | - Johann Lubieniecki
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | | | - Jürgen Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Harald Engelhardt
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Lena F Kourkoutis
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
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14
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Hood D, Sahin T, Parkes‐Loach PS, Jiao J, Harris MA, Dilbeck P, Niedzwiedzki DM, Kirmaier C, Loach PA, Bocian DF, Lindsey JS, Holten D. Expanding Covalent Attachment Sites of Nonnative Chromophores to Encompass the C‐Terminal Hydrophilic Domain in Biohybrid Light‐Harvesting Architectures. CHEMPHOTOCHEM 2018. [DOI: 10.1002/cptc.201700182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Don Hood
- Department of Chemistry Washington University St. Louis MO 63130-4889 USA
| | - Tuba Sahin
- Department of Chemistry North Carolina State University Raleigh NC 27695-8204 USA
| | | | - Jieying Jiao
- Department of Chemistry University of California Riverside CA 92521-0403 USA
| | - Michelle A. Harris
- Department of Chemistry Washington University St. Louis MO 63130-4889 USA
| | - Preston Dilbeck
- Department of Chemistry Washington University St. Louis MO 63130-4889 USA
| | | | - Christine Kirmaier
- Department of Chemistry Washington University St. Louis MO 63130-4889 USA
| | - Paul A. Loach
- Department of Molecular Biosciences Northwestern University Evanston IL 60208-3500 USA
| | - David F. Bocian
- Department of Chemistry University of California Riverside CA 92521-0403 USA
| | - Jonathan S. Lindsey
- Department of Chemistry North Carolina State University Raleigh NC 27695-8204 USA
| | - Dewey Holten
- Department of Chemistry Washington University St. Louis MO 63130-4889 USA
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15
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Gao D, Aly SM, Karsenti PL, Brisard G, Harvey PD. Increasing the lifetimes of charge separated states in porphyrin-fullerene polyads. Phys Chem Chem Phys 2018; 19:24018-24028. [PMID: 28832037 DOI: 10.1039/c7cp04193d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two linear polyads were designed using zinc(ii)porphyrin, [ZnP], and N-methyl-2-phenyl-3,4-fullero-pyrrolidine (C60) where C60 is dangling either at the terminal position of [ZnP]-C6H4-[triple bond, length as m-dash]-C6H4-[ZnP]-C60 (1) or at the central position of [ZnP]-C6H4-[triple bond, length as m-dash]-C6H4-[ZnP(C60)]-C6H4-[triple bond, length as m-dash]-C6H4-[ZnP] (2) in order to test whether the fact of having one or two side electron donors influences the rate of electron transfer, ket. These polyads were studied using cyclic voltammograms, DFT computations, steady state and time-resolved fluorescence spectroscopy, and femtosecond transient absorption spectroscopy (fs-TAS). Photo-induced electron transfer confirmed by the detection of the charge separated state [ZnP˙+]/C60˙- from fs-TAS occurs with rates (ket) of 3-4 × 1010 s-1 whereas the charge recombinations (CRs) are found to produce the [ZnP] ground state via two pathways (central [ZnP˙+]/C60˙- (ps) and terminal central [ZnP˙+]/C60˙- (ns) producing [1ZnP] (ground state) and [3ZnP*]). The formation of the T1 species is more predominant for 2.
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Affiliation(s)
- Di Gao
- Departement de Chimie, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada.
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16
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Swainsbury DJK, Martin EC, Vasilev C, Parkes-Loach PS, Loach PA, Neil Hunter C. Engineering of a calcium-ion binding site into the RC-LH1-PufX complex of Rhodobacter sphaeroides to enable ion-dependent spectral red-shifting. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:927-938. [PMID: 28826909 PMCID: PMC5604489 DOI: 10.1016/j.bbabio.2017.08.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/02/2017] [Accepted: 08/17/2017] [Indexed: 01/01/2023]
Abstract
The reaction centre-light harvesting 1 (RC-LH1) complex of Thermochromatium (Tch.) tepidum has a unique calcium-ion binding site that enhances thermal stability and red-shifts the absorption of LH1 from 880nm to 915nm in the presence of calcium-ions. The LH1 antenna of mesophilic species of phototrophic bacteria such as Rhodobacter (Rba.) sphaeroides does not possess such properties. We have engineered calcium-ion binding into the LH1 antenna of Rba. sphaeroides by progressively modifying the native LH1 polypeptides with sequences from Tch. tepidum. We show that acquisition of the C-terminal domains from LH1 α and β of Tch. tepidum is sufficient to activate calcium-ion binding and the extent of red-shifting increases with the proportion of Tch. tepidum sequence incorporated. However, full exchange of the LH1 polypeptides with those of Tch. tepidum results in misassembled core complexes. Isolated α and β polypeptides from our most successful mutant were reconstituted in vitro with BChl a to form an LH1-type complex, which was stabilised 3-fold by calcium-ions. Additionally, carotenoid specificity was changed from spheroidene found in Rba. sphaeroides to spirilloxanthin found in Tch. tepidum, with the latter enhancing in vitro formation of LH1. These data show that the C-terminal LH1 α/β domains of Tch. tepidum behave autonomously, and are able to transmit calcium-ion induced conformational changes to BChls bound to the rest of a foreign antenna complex. Thus, elements of foreign antenna complexes, such as calcium-ion binding and blue/red switching of absorption, can be ported into Rhodobacter sphaeroides using careful design processes.
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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.
| | - Elizabeth C Martin
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom
| | - Pamela S Parkes-Loach
- Department of Molecular Biosciences, Northwestern University, Hogan 2100, 2205 Tech Drive, Evanston, IL 60208, United States
| | - Paul A Loach
- Department of Molecular Biosciences, Northwestern University, Hogan 2100, 2205 Tech Drive, Evanston, IL 60208, United States
| | - 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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17
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Hitchcock A, Hunter CN, Sener M. Determination of Cell Doubling Times from the Return-on-Investment Time of Photosynthetic Vesicles Based on Atomic Detail Structural Models. J Phys Chem B 2017; 121:3787-3797. [PMID: 28301162 DOI: 10.1021/acs.jpcb.6b12335] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cell doubling times of the purple bacterium Rhodobacter sphaeroides during photosynthetic growth are determined experimentally and computationally as a function of illumination. For this purpose, energy conversion processes in an intracytoplasmic membrane vesicle, the chromatophore, are described based on an atomic detail structural model. The cell doubling time and its illumination dependence are computed in terms of the return-on-investment (ROI) time of the chromatophore, determined computationally from the ATP production rate, and the mass ratio of chromatophores in the cell, determined experimentally from whole cell absorbance spectra. The ROI time is defined as the time it takes to produce enough ATP to pay for the construction of another chromatophore. The ROI time of the low light-growth chromatophore is 4.5-2.6 h for a typical illumination range of 10-100 μmol photons m-2 s-1, respectively, with corresponding cell doubling times of 8.2-3.9 h. When energy expenditure is considered as a currency, the benefit-to-cost ratio computed for the chromatophore as an energy harvesting device is 2-8 times greater than for photovoltaic and fossil fuel-based energy solutions and the corresponding ROI times are approximately 3-4 orders of magnitude shorter for the chromatophore than for synthetic systems.
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Affiliation(s)
- Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield , Sheffield S10 2TN, U.K
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield , Sheffield S10 2TN, U.K
| | - Melih Sener
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.,Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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18
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Augmenting light coverage for photosynthesis through YFP-enhanced charge separation at the Rhodobacter sphaeroides reaction centre. Nat Commun 2017; 8:13972. [PMID: 28054547 PMCID: PMC5512671 DOI: 10.1038/ncomms13972] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/17/2016] [Indexed: 12/31/2022] Open
Abstract
Photosynthesis uses a limited range of the solar spectrum, so enhancing spectral coverage could improve the efficiency of light capture. Here, we show that a hybrid reaction centre (RC)/yellow fluorescent protein (YFP) complex accelerates photosynthetic growth in the bacterium Rhodobacter sphaeroides. The structure of the RC/YFP-light-harvesting 1 (LH1) complex shows the position of YFP attachment to the RC-H subunit, on the cytoplasmic side of the RC complex. Fluorescence lifetime microscopy of whole cells and ultrafast transient absorption spectroscopy of purified RC/YFP complexes show that the YFP–RC intermolecular distance and spectral overlap between the emission of YFP and the visible-region (QX) absorption bands of the RC allow energy transfer via a Förster mechanism, with an efficiency of 40±10%. This proof-of-principle study demonstrates the feasibility of increasing spectral coverage for harvesting light using non-native genetically-encoded light-absorbers, thereby augmenting energy transfer and trapping in photosynthesis. Photosynthesis uses only a limited range of solar radiation. Here, Grayson et al. genetically incorporated the yellow fluorescent protein (YFP) chromophore into a bacterial photosystem, and show that energy harvested by reaction centre–YFP complexes can augment photosynthesis in vivo.
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19
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Charalambidis G, Georgilis E, Panda MK, Anson CE, Powell AK, Doyle S, Moss D, Jochum T, Horton PN, Coles SJ, Linares M, Beljonne D, Naubron JV, Conradt J, Kalt H, Mitraki A, Coutsolelos AG, Balaban TS. A switchable self-assembling and disassembling chiral system based on a porphyrin-substituted phenylalanine-phenylalanine motif. Nat Commun 2016; 7:12657. [PMID: 27582363 PMCID: PMC5025786 DOI: 10.1038/ncomms12657] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 07/18/2016] [Indexed: 01/01/2023] Open
Abstract
Artificial light-harvesting systems have until now not been able to self-assemble into structures with a large photon capture cross-section that upon a stimulus reversibly can switch into an inactive state. Here we describe a simple and robust FLFL-dipeptide construct to which a meso-tetraphenylporphyrin has been appended and which self-assembles to fibrils, platelets or nanospheres depending on the solvent composition. The fibrils, functioning as quenched antennas, give intense excitonic couplets in the electronic circular dichroism spectra which are mirror imaged if the unnatural FDFD-analogue is used. By slightly increasing the solvent polarity, these light-harvesting fibres disassemble to spherical structures with silent electronic circular dichroism spectra but which fluoresce. Upon further dilution with the nonpolar solvent, the intense Cotton effects are recovered, thus proving a reversible switching. A single crystal X-ray structure shows a head-to-head arrangement of porphyrins that explains both their excitonic coupling and quenched fluorescence.
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Affiliation(s)
- Georgios Charalambidis
- Department of Chemistry, Bioinorganic Chemistry Laboratory, University of Crete, Vassilika Vouton, Heraklion, 70013 Crete, Greece
| | - Evangelos Georgilis
- Department of Materials Science and Technology, University of Crete, Vassilika Vouton, Heraklion, 70013 Crete, Greece
- Institute of Electronic Structure and Laser (I.E.S.L.) Foundation for Research and Technology Hellas (FO.R.T.H.) Vassilika Vouton, Heraklion, 70013 Crete, Greece
| | - Manas K. Panda
- Department of Chemistry, Bioinorganic Chemistry Laboratory, University of Crete, Vassilika Vouton, Heraklion, 70013 Crete, Greece
| | - Christopher E. Anson
- Karlsruhe Institute of Technology (KIT), Institute of Inorganic Chemistry, Engesserstrasse 15, D-76131 Karlsruhe, Germany
| | - Annie K. Powell
- Karlsruhe Institute of Technology (KIT), Institute of Inorganic Chemistry, Engesserstrasse 15, D-76131 Karlsruhe, Germany
- Karlsruhe Institute of Technology (KIT), Institute for Nanotechnology (INT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Stephen Doyle
- Karlsruhe Institute of Technology, Institute for Synchrotron Radiation and ANKA, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - David Moss
- Karlsruhe Institute of Technology, Institute for Synchrotron Radiation and ANKA, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Tobias Jochum
- Karlsruhe Institute of Technology, Institute for Synchrotron Radiation and ANKA, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Peter N. Horton
- School of Chemistry, EPSRC National Crystallography Service, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Simon J. Coles
- School of Chemistry, EPSRC National Crystallography Service, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Mathieu Linares
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
- Swedish e-Science Research Centre (SeRC), Linköping University, SE-581 83 Linköping, Sweden
| | - David Beljonne
- Département de Chimie, Chimie des Matériaux Nouveaux and Centre d'Innovation et de Recherche en Matériaux Polymères, Université de Mons—UMONS/Materia Nova, Place du Parc, 20, B-7000 Mons, Belgium
| | - Jean-Valère Naubron
- Aix Marseille Université, CNRS FR 1739, Spectropole, Avenue Escadrille Normandie Niemen, F-13397 Marseille, France
| | - Jonas Conradt
- Karlsruhe Institute of Technology (KIT), Institute of Applied Physics and Center for Functional Nanostructures (CFN), D-76131 Karlsruhe, Germany
| | - Heinz Kalt
- Karlsruhe Institute of Technology (KIT), Institute of Applied Physics and Center for Functional Nanostructures (CFN), D-76131 Karlsruhe, Germany
| | - Anna Mitraki
- Department of Materials Science and Technology, University of Crete, Vassilika Vouton, Heraklion, 70013 Crete, Greece
- Institute of Electronic Structure and Laser (I.E.S.L.) Foundation for Research and Technology Hellas (FO.R.T.H.) Vassilika Vouton, Heraklion, 70013 Crete, Greece
| | - Athanassios G. Coutsolelos
- Department of Chemistry, Bioinorganic Chemistry Laboratory, University of Crete, Vassilika Vouton, Heraklion, 70013 Crete, Greece
| | - Teodor Silviu Balaban
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut des Sciences Moléculaires de Marseille (iSm2), UMR 7313, Chirosciences, Avenue Escadrille Normandie Niemen, Service 442, F-13397 Marseille, France
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20
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Sener M, Strumpfer J, Singharoy A, Hunter CN, Schulten K. Overall energy conversion efficiency of a photosynthetic vesicle. eLife 2016; 5. [PMID: 27564854 PMCID: PMC5001839 DOI: 10.7554/elife.09541] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 07/11/2016] [Indexed: 11/25/2022] Open
Abstract
The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytbc1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%–5% of full sunlight is calculated to be 0.12–0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination. DOI:http://dx.doi.org/10.7554/eLife.09541.001 Photosynthesis, or the conversion of light energy into chemical energy, is a process that powers almost all life on Earth. Plants and certain bacteria share similar processes to perform photosynthesis, though the purple bacterium Rhodobacter sphaeroides uses a photosynthetic system that is much less complex than that in plants. Light harvesting inside the bacterium takes place in up to hundreds of compartments called chromatophores. Each chromatophore in turn contains hundreds of cooperating proteins that together absorb the energy of sunlight and convert and store it in molecules of ATP, the universal energy currency of all cells. The chromatophore of primitive purple bacteria provides a model for more complex photosynthetic systems in plants. Though researchers had characterized its individual components over the years, less was known about the overall architecture of the chromatophore and how its many components work together to harvest light energy efficiently and robustly. This knowledge would provide insight into the evolutionary pressures that shaped the chromatophore and its ability to work efficiently at different light intensities. Sener et al. now present a highly detailed structural model of the chromatophore of purple bacteria based on the findings of earlier studies. The model features the position of every atom of the constituent proteins and is used to examine how energy is transferred and converted. Sener et al. describe the sequence of energy conversion steps and calculate the overall energy conversion efficiency, namely how much of the light energy arriving at the microorganism is stored as ATP. These calculations show that the chromatophore is optimized to produce chemical energy at low light levels typical of purple bacterial habitats, and dissipate excess energy to avoid being damaged under brighter light. The chromatophore’s architecture also displays robustness against perturbations of its components. In the future, the approach used by Sener et al. to describe light harvesting in this bacterial compartment can be applied to more complex systems, such as those in plants. DOI:http://dx.doi.org/10.7554/eLife.09541.002
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Affiliation(s)
- Melih Sener
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Johan Strumpfer
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States.,Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Abhishek Singharoy
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - 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, United States.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States.,Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, United States
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21
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Mothersole DJ, Jackson PJ, Vasilev C, Tucker JD, Brindley AA, Dickman MJ, Hunter CN. PucC and LhaA direct efficient assembly of the light-harvesting complexes in Rhodobacter sphaeroides. Mol Microbiol 2015; 99:307-27. [PMID: 26419219 PMCID: PMC4949548 DOI: 10.1111/mmi.13235] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2015] [Indexed: 01/21/2023]
Abstract
The mature architecture of the photosynthetic membrane of the purple phototroph Rhodobacter sphaeroides has been characterised to a level where an atomic-level membrane model is available, but the roles of the putative assembly proteins LhaA and PucC in establishing this architecture are unknown. Here we investigate the assembly of light-harvesting LH2 and reaction centre-light-harvesting1-PufX (RC-LH1-PufX) photosystem complexes using spectroscopy, pull-downs, native gel electrophoresis, quantitative mass spectrometry and fluorescence lifetime microscopy to characterise a series of lhaA and pucC mutants. LhaA and PucC are important for specific assembly of LH1 or LH2 complexes, respectively, but they are not essential; the few LH1 subunits found in ΔlhaA mutants assemble to form normal RC-LH1-PufX core complexes showing that, once initiated, LH1 assembly round the RC is cooperative and proceeds to completion. LhaA and PucC form oligomers at sites of initiation of membrane invagination; LhaA associates with RCs, bacteriochlorophyll synthase (BchG), the protein translocase subunit YajC and the YidC membrane protein insertase. These associations within membrane nanodomains likely maximise interactions between pigments newly arriving from BchG and nascent proteins within the SecYEG-SecDF-YajC-YidC assembly machinery, thereby co-ordinating pigment delivery, the co-translational insertion of LH polypeptides and their folding and assembly to form photosynthetic complexes.
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Affiliation(s)
- David J Mothersole
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Philip J Jackson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK.,ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Jaimey D Tucker
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Amanda A Brindley
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Mark J Dickman
- ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
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22
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Yoneda Y, Noji T, Katayama T, Mizutani N, Komori D, Nango M, Miyasaka H, Itoh S, Nagasawa Y, Dewa T. Extension of Light-Harvesting Ability of Photosynthetic Light-Harvesting Complex 2 (LH2) through Ultrafast Energy Transfer from Covalently Attached Artificial Chromophores. J Am Chem Soc 2015; 137:13121-9. [DOI: 10.1021/jacs.5b08508] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yusuke Yoneda
- Graduate
School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Tomoyasu Noji
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
- The OCU Advanced Research Institute for Natural Science & Technology (OCARINA), Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Tetsuro Katayama
- Institute
for NanoScience Design, Osaka University, Toyonaka, Osaka 560-8531, Japan
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Naoto Mizutani
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Daisuke Komori
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Mamoru Nango
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
- The OCU Advanced Research Institute for Natural Science & Technology (OCARINA), Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Hiroshi Miyasaka
- Graduate
School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Shigeru Itoh
- Center for
Gene Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Yutaka Nagasawa
- Graduate
School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Takehisa Dewa
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
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23
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Lewis NHC, Dong H, Oliver TAA, Fleming GR. A method for the direct measurement of electronic site populations in a molecular aggregate using two-dimensional electronic-vibrational spectroscopy. J Chem Phys 2015; 143:124203. [DOI: 10.1063/1.4931634] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Nicholas H. C. Lewis
- Department of Chemistry, University of California, Berkeley, California 94720, USA; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; and Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720, USA
| | - Hui Dong
- Department of Chemistry, University of California, Berkeley, California 94720, USA; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; and Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720, USA
| | - Thomas A. A. Oliver
- Department of Chemistry, University of California, Berkeley, California 94720, USA; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; and Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720, USA
| | - Graham R. Fleming
- Department of Chemistry, University of California, Berkeley, California 94720, USA; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; and Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720, USA
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24
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Wang G, Chang X, Peng J, Liu K, Zhao K, Yu C, Fang Y. Towards a new FRET system via combination of pyrene and perylene bisimide: synthesis, self-assembly and fluorescence behavior. Phys Chem Chem Phys 2015; 17:5441-9. [PMID: 25615443 DOI: 10.1039/c4cp04860a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A new fluorescent derivative of cholesterol, N,N'-(N-(2-(3β-cholest-5-en-3yl-formamido)ethyl) pyrene-1-sulfonamido)ethyl perylene-3,4:9,10-tetracarboxylic acid bisimide (CPPBI), was designed and synthesized. In the design, pyrene (Py) and perylene bisimide (PBI) were specially chosen as the energy donor and the acceptor, respectively. Fluorescence studies revealed that (1) CPPBI shows a strong tendency to form supra-molecular assemblies, (2) the assemblies possess a high efficiency of fluorescence resonance energy transfer (FRET) via intermolecular interactions, and (3) the profile and position of its fluorescence emission are highly dependent upon the nature of its medium, but the medium shows little effect on the efficiency of the energy transfer, suggesting that the chromophores including both Py and PBI units enjoy some rotational and/or translational mobility in the aggregated state of the compound. Temperature- and concentration-dependent (1)H NMR spectroscopy studies revealed that both hydrogen-bonding and π-π stacking play a great role in stabilizing the assemblies of the compound, and confirmed the existence of π-π stacking between the Py moieties and between the PBI residues of the compound, of which the donor and the acceptor may have arranged in an appropriate orientation and at a suitable distance which are the key factors to determine the FRET efficiency. Moreover, the CPPBI-based film possesses unusual photochemical stability, and its emission is sensitive to the presence of some organic vapors, in particular aniline.
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Affiliation(s)
- Gang Wang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, P. R. China.
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25
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Gu Y, Ellis-Guardiola K, Srivastava P, Lewis JC. Preparation, Characterization, and Oxygenase Activity of a Photocatalytic Artificial Enzyme. Chembiochem 2015; 16:1880-1883. [PMID: 26097041 DOI: 10.1002/cbic.201500165] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Indexed: 11/12/2022]
Abstract
A bicyclo[6,1,0]nonyne-substituted 9-mesityl-10-methyl-acridinium cofactor was prepared and covalently linked to a prolyl oligopeptidase scaffold containing a genetically encoded 4-azido-L-phenylalanine residue in its active site. The resulting artificial enzyme catalyzed sulfoxidation when irradiated with visible light in the presence of air. This reaction proceeds by initial electron abstraction from the sulfide within the enzyme active site, and the protein scaffold extended the fluorescence lifetime of the acridium cofactor. The mode of sulfide activation and placement of the acridinium cofactor (5) in POP-ZA4 -5 make this artificial enzyme a promising platform for developing selective photocatalytic transformations.
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Affiliation(s)
- Yifan Gu
- Department of Chemistry, University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637 (USA)
| | - Ken Ellis-Guardiola
- Department of Chemistry, University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637 (USA)
| | - Poonam Srivastava
- Department of Chemistry, University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637 (USA)
| | - Jared C Lewis
- Department of Chemistry, University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637 (USA)
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Adams PG, Collins AM, Sahin T, Subramanian V, Urban VS, Vairaprakash P, Tian Y, Evans DG, Shreve AP, Montaño GA. Diblock copolymer micelles and supported films with noncovalently incorporated chromophores: a modular platform for efficient energy transfer. NANO LETTERS 2015; 15:2422-2428. [PMID: 25719733 DOI: 10.1021/nl504814x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report generation of modular, artificial light-harvesting assemblies where an amphiphilic diblock copolymer, poly(ethylene oxide)-block-poly(butadiene), serves as the framework for noncovalent organization of BODIPY-based energy donor and bacteriochlorin-based energy acceptor chromophores. The assemblies are adaptive and form well-defined micelles in aqueous solution and high-quality monolayer and bilayer films on solid supports, with the latter showing greater than 90% energy transfer efficiency. This study lays the groundwork for further development of modular, polymer-based materials for light harvesting and other photonic applications.
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Affiliation(s)
- Peter G Adams
- †Center for Integrated Nanotechnologies, Los Alamos National Laboratories, Los Alamos, New Mexico 87545, United States
| | - Aaron M Collins
- †Center for Integrated Nanotechnologies, Los Alamos National Laboratories, Los Alamos, New Mexico 87545, United States
| | - Tuba Sahin
- ‡Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Vijaya Subramanian
- §Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Volker S Urban
- ⊥Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Pothiappan Vairaprakash
- ‡Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Yongming Tian
- †Center for Integrated Nanotechnologies, Los Alamos National Laboratories, Los Alamos, New Mexico 87545, United States
- ¶Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, United States
| | - Deborah G Evans
- §Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Andrew P Shreve
- §Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Gabriel A Montaño
- †Center for Integrated Nanotechnologies, Los Alamos National Laboratories, Los Alamos, New Mexico 87545, United States
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Harriman A. Artificial light-harvesting arrays for solar energy conversion. Chem Commun (Camb) 2015; 51:11745-56. [DOI: 10.1039/c5cc03577e] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Following natures' blueprint, the concept of artificial light-harvesting antennae is discussed in terms of sophisticated molecular arrays displaying a tailored cascade of electronic energy transfer steps.
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Affiliation(s)
- Anthony Harriman
- Molecular Photonics Laboratory
- School of Chemistry
- Bedson Building
- Newcastle University
- Newcastle upon Tyne
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28
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Jiang J, Reddy KR, Pavan MP, Lubian E, Harris MA, Jiao J, Niedzwiedzki DM, Kirmaier C, Parkes-Loach PS, Loach PA, Bocian DF, Holten D, Lindsey JS. Amphiphilic, hydrophilic, or hydrophobic synthetic bacteriochlorins in biohybrid light-harvesting architectures: consideration of molecular designs. PHOTOSYNTHESIS RESEARCH 2014; 122:187-202. [PMID: 24997120 DOI: 10.1007/s11120-014-0021-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 05/26/2014] [Indexed: 06/03/2023]
Abstract
Biohybrid light-harvesting architectures can be constructed that employ native-like bacterial photosynthetic antenna peptides as a scaffold to which synthetic chromophores are attached to augment overall spectral coverage. Synthetic bacteriochlorins are attractive to enhance capture of solar radiation in the photon-rich near-infrared spectral region. The effect of the polarity of the bacteriochlorin substituents on the antenna self-assembly process was explored by the preparation of a bacteriochlorin-peptide conjugate using a synthetic amphiphilic bacteriochlorin (B1) to complement prior studies using hydrophilic (B2, four carboxylic acids) or hydrophobic (B3) bacteriochlorins. The amphiphilic bioconjugatable bacteriochlorin B1 with a polar ammonium-terminated tail was synthesized by sequential Pd-mediated reactions of a 3,13-dibromo-5-methoxybacteriochlorin. Each bacteriochlorin bears a maleimido-terminated tether for attachment to a cysteine-containing analog of the Rhodobacter sphaeroides antenna β-peptide to give conjugates β-B1, β-B2, and β-B3. Given the hydrophobic nature of the β-peptide, the polarity of B1 and B2 facilitated purification of the respective conjugate compared to the hydrophobic B3. Bacteriochlorophyll a (BChl a) associates with each conjugate in aqueous micellar media to form a dyad containing two β-peptides, two covalently attached synthetic bacteriochlorins, and a datively bonded BChl-a pair, albeit to a limited extent for β-B2. The reversible assembly/disassembly of dyad (β-B2/BChl)2 was examined in aqueous detergent (octyl glucoside) solution by temperature variation (15-35 °C). The energy-transfer efficiency from the synthetic bacteriochlorin to the BChl-a dimer was found to be 0.85 for (β-B1/BChl)2, 0.40 for (β-B2/BChl)2, and 0.85 for (β-B3/BChl)2. Thus, in terms of handling, assembly and energy-transfer efficiency taken together, the amphiphilic design examined herein is more attractive than the prior hydrophilic or hydrophobic designs.
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Affiliation(s)
- Jianbing Jiang
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
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Harris MA, Sahin T, Jiang J, Vairaprakash P, Parkes-Loach PS, Niedzwiedzki DM, Kirmaier C, Loach PA, Bocian DF, Holten D, Lindsey JS. Enhanced Light-Harvesting Capacity by Micellar Assembly of Free Accessory Chromophores and LH1-like Antennas. Photochem Photobiol 2014; 90:1264-76. [DOI: 10.1111/php.12319] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/11/2014] [Indexed: 01/05/2023]
Affiliation(s)
| | - Tuba Sahin
- Department of Chemistry; North Carolina State University; Raleigh NC
| | - Jianbing Jiang
- Department of Chemistry; North Carolina State University; Raleigh NC
| | | | | | | | | | - Paul A. Loach
- Department of Molecular Biosciences; Northwestern University; Evanston IL
| | - David F. Bocian
- Department of Chemistry; University of California; Riverside CA
| | - Dewey Holten
- Department of Chemistry; Washington University; St. Louis MO
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Taniguchi M, Henry S, Cogdell RJ, Lindsey JS. Statistical considerations on the formation of circular photosynthetic light-harvesting complexes from Rhodopseudomonas palustris. PHOTOSYNTHESIS RESEARCH 2014; 121:49-60. [PMID: 24510549 DOI: 10.1007/s11120-014-9975-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 01/15/2014] [Indexed: 06/03/2023]
Abstract
Depending on growth conditions, some species of purple photosynthetic bacteria contain peripheral light-harvesting (LH2) complexes that are heterogeneous owing to the presence of different protomers (containing different αβ-apoproteins). Recent spectroscopic studies of Rhodopseudomonas palustris grown under low-light conditions suggest the presence of a C 3-symmetric LH2 nonamer comprised of two distinct protomers. The software program Cyclaplex, which enables generation and data-mining of virtual libraries of molecular rings formed upon combinatorial reactions, has been used to delineate the possible number and type of distinct nonamers as a function of numbers of distinct protomers. The yield of the C 3-symmetric nonamer from two protomers (A and B in varying ratios) has been studied under the following conditions: (1) statistical, (2) enriched (preclusion of the B-B sequence), and (3) seeded (pre-formation of an A-B-A block). The yield of C 3-symmetric nonamer is at most 0.98 % under statistical conditions versus 5.6 % under enriched conditions, and can be dominant under conditions of pre-seeding with an A-B-A block. In summary, the formation of any one specific nonamer even from only two protomers is unlikely on statistical grounds but must stem from enhanced free energy of formation or a directed assembly process by as-yet unknown factors.
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Affiliation(s)
- Masahiko Taniguchi
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA,
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Harris MA, Jiang J, Niedzwiedzki DM, Jiao J, Taniguchi M, Kirmaier C, Loach PA, Bocian DF, Lindsey JS, Holten D, Parkes-Loach PS. Versatile design of biohybrid light-harvesting architectures to tune location, density, and spectral coverage of attached synthetic chromophores for enhanced energy capture. PHOTOSYNTHESIS RESEARCH 2014; 121:35-48. [PMID: 24604033 DOI: 10.1007/s11120-014-9993-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 02/22/2014] [Indexed: 06/03/2023]
Abstract
Biohybrid antennas built upon chromophore-polypeptide conjugates show promise for the design of efficient light-capturing modules for specific purposes. Three new designs, each of which employs analogs of the β-polypeptide from Rhodobacter sphaeroides, have been investigated. In the first design, amino acids at seven different positions on the polypeptide were individually substituted with cysteine, to which a synthetic chromophore (bacteriochlorin or Oregon Green) was covalently attached. The polypeptide positions are at -2, -6, -10, -14, -17, -21, and -34 relative to the 0-position of the histidine that coordinates bacteriochlorophyll a (BChl a). All chromophore-polypeptides readily formed LH1-type complexes upon combination with the α-polypeptide and BChl a. Efficient energy transfer occurs from the attached chromophore to the circular array of 875 nm absorbing BChl a molecules (denoted B875). In the second design, use of two attachment sites (positions -10 and -21) on the polypeptide affords (1) double the density of chromophores per polypeptide and (2) a highly efficient energy-transfer relay from the chromophore at -21 to that at -10 and on to B875. In the third design, three spectrally distinct bacteriochlorin-polypeptides were prepared (each attached to cysteine at the -14 position) and combined in an ~1:1:1 mixture to form a heterogeneous mixture of LH1-type complexes with increased solar coverage and nearly quantitative energy transfer from each bacteriochlorin to B875. Collectively, the results illustrate the great latitude of the biohybrid approach for the design of diverse light-harvesting systems.
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Affiliation(s)
- Michelle A Harris
- Department of Chemistry, Washington University, St. Louis, MO, 63130-4889, USA
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Jiang J, Vairaprakash P, Reddy KR, Sahin T, Pavan MP, Lubian E, Lindsey JS. Hydrophilic tetracarboxy bacteriochlorins for photonics applications. Org Biomol Chem 2014; 12:86-103. [DOI: 10.1039/c3ob41791c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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