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Lyratzakis A, Daskalakis V, Xie H, Tsiotis G. The synergy between the PscC subunits for electron transfer to the P 840 special pair in Chlorobaculum tepidum. PHOTOSYNTHESIS RESEARCH 2024; 160:87-96. [PMID: 38625595 PMCID: PMC11108878 DOI: 10.1007/s11120-024-01093-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 03/08/2024] [Indexed: 04/17/2024]
Abstract
The primary photochemical reaction of photosynthesis in green sulfur bacteria occurs in the homodimer PscA core proteins by a special chlorophyll pair. The light induced excited state of the special pair producing P840+ is rapidly reduced by electron transfer from one of the two PscC subunits. Molecular dynamics (MD) simulations are combined with bioinformatic tools herein to provide structural and dynamic insight into the complex between the two PscA core proteins and the two PscC subunits. The microscopic dynamic model involves extensive sampling at atomic resolution and at a cumulative time-scale of 22µs and reveals well defined protein-protein interactions. The membrane complex is composed of the two PscA and the two PscC subunits and macroscopic connections are revealed within a putative electron transfer pathway from the PscC subunit to the special pair P840 located within the PscA subunits. Our results provide a structural basis for understanding the electron transport to the homodimer RC of the green sulfur bacteria. The MD based approach can provide the basis to further probe the PscA-PscC complex dynamics and observe electron transfer therein at the quantum level. Furthermore, the transmembrane helices of the different PscC subunits exert distinct dynamics in the complex.
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Affiliation(s)
- Alexandros Lyratzakis
- Department of Chemistry, School of Science and Engineering, University of Crete, Heraklion, 70013, Greece
| | - Vangelis Daskalakis
- Department of Chemical Engineering, School of Engineering, University of Patras, Rion, Patras, 26504, Greece
| | - Hao Xie
- Max Planck Institute of Biophysics, 60438, Frankfurt am Main, Germany
| | - Georgios Tsiotis
- Department of Chemistry, School of Science and Engineering, University of Crete, Heraklion, 70013, Greece.
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2
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Rasul F, You D, Jiang Y, Liu X, Daroch M. Thermophilic cyanobacteria-exciting, yet challenging biotechnological chassis. Appl Microbiol Biotechnol 2024; 108:270. [PMID: 38512481 PMCID: PMC10957709 DOI: 10.1007/s00253-024-13082-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/23/2024]
Abstract
Thermophilic cyanobacteria are prokaryotic photoautotrophic microorganisms capable of growth between 45 and 73 °C. They are typically found in hot springs where they serve as essential primary producers. Several key features make these robust photosynthetic microbes biotechnologically relevant. These are highly stable proteins and their complexes, the ability to actively transport and concentrate inorganic carbon and other nutrients, to serve as gene donors, microbial cell factories, and sources of bioactive metabolites. A thorough investigation of the recent progress in thermophilic cyanobacteria reveals a significant increase in the number of newly isolated and delineated organisms and wide application of thermophilic light-harvesting components in biohybrid devices. Yet despite these achievements, there are still deficiencies at the high-end of the biotechnological learning curve, notably in genetic engineering and gene editing. Thermostable proteins could be more widely employed, and an extensive pool of newly available genetic data could be better utilised. In this manuscript, we attempt to showcase the most important recent advances in thermophilic cyanobacterial biotechnology and provide an overview of the future direction of the field and challenges that need to be overcome before thermophilic cyanobacterial biotechnology can bridge the gap with highly advanced biotechnology of their mesophilic counterparts. KEY POINTS: • Increased interest in all aspects of thermophilic cyanobacteria in recent years • Light harvesting components remain the most biotechnologically relevant • Lack of reliable molecular biology tools hinders further development of the chassis.
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Affiliation(s)
- Faiz Rasul
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Dawei You
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Ying Jiang
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Xiangjian Liu
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Maurycy Daroch
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
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3
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Mäusle SM, Agarwala N, Eichmann VG, Dau H, Nürnberg DJ, Hastings G. Nanosecond time-resolved infrared spectroscopy for the study of electron transfer in photosystem I. PHOTOSYNTHESIS RESEARCH 2024; 159:229-239. [PMID: 37420121 PMCID: PMC10991071 DOI: 10.1007/s11120-023-01035-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 06/21/2023] [Indexed: 07/09/2023]
Abstract
Microsecond time-resolved step-scan FTIR difference spectroscopy was used to study photosystem I (PSI) from Thermosynechococcus vestitus BP-1 (T. vestitus, formerly known as T. elongatus) at 77 K. In addition, photoaccumulated (P700+-P700) FTIR difference spectra were obtained at both 77 and 293 K. The FTIR difference spectra are presented here for the first time. To extend upon these FTIR studies nanosecond time-resolved infrared difference spectroscopy was also used to study PSI from T. vestitus at 296 K. Nanosecond infrared spectroscopy has never been used to study PSI samples at physiological temperatures, and here it is shown that such an approach has great value as it allows a direct probe of electron transfer down both branches in PSI. In PSI at 296 K, the infrared flash-induced absorption changes indicate electron transfer down the B- and A-branches is characterized by time constants of 33 and 364 ns, respectively, in good agreement with visible spectroscopy studies. These time constants are associated with forward electron transfer from A1- to FX on the B- and A-branches, respectively. At several infrared wavelengths flash-induced absorption changes at 296 K recover in tens to hundreds of milliseconds. The dominant decay phase is characterized by a lifetime of 128 ms. These millisecond changes are assigned to radical pair recombination reactions, with the changes being associated primarily with P700+ rereduction. This conclusion follows from the observation that the millisecond infrared spectrum is very similar to the photoaccumulated (P700+-P700) FTIR difference spectrum.
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Affiliation(s)
- Sarah M Mäusle
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Neva Agarwala
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA, 30303, USA
- Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA
| | - Viktor G Eichmann
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Holger Dau
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
| | - Dennis J Nürnberg
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
- Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany.
| | - Gary Hastings
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA, 30303, USA.
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4
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Than L, Wolfe KD, Cliffel DE, Jennings GK. Drop-casted Photosystem I/cytochrome c multilayer films for biohybrid solar energy conversion. PHOTOSYNTHESIS RESEARCH 2023; 155:299-308. [PMID: 36564600 DOI: 10.1007/s11120-022-00993-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
One of the main barriers to making efficient Photosystem I-based biohybrid solar cells is the need for an electrochemical pathway to facilitate electron transfer between the P700 reaction center of Photosystem I and an electrode. To this end, nature provides inspiration in the form of cytochrome c6, a natural electron donor to the P700 site. Its natural ability to access the P700 binding pocket and reduce the reaction center can be mimicked by employing cytochrome c, which has a similar protein structure and redox chemistry while also being compatible with a variety of electrode surfaces. Previous research has incorporated cytochrome c to improve the photocurrent generation of Photosystem I using time consuming and/or specialized electrode preparation. While those methods lead to high protein areal density, in this work we use the quick and facile vacuum-assisted drop-casting technique to construct a Photosystem I/cytochrome c photoactive composite film with micron-scale thickness. We demonstrate that this simple fabrication technique can result in high cytochrome c loading and improvement in cathodic photocurrent over a drop-casted Photosystem I film without cytochrome c. In addition, we analyze the behavior of the cytochrome c/Photosystem I system at varying applied potentials to show that the improvement in performance can be attributed to enhancement of the electron transfer rate to P700 sites and therefore the PSI turnover rate within the composite film.
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Affiliation(s)
- Long Than
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235-1604, USA
| | - Kody D Wolfe
- Interdisciplinary Materials Science and Engineering Program, Vanderbilt University, Nashville, TN, 37235-0106, USA
| | - David E Cliffel
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235-1822, USA
| | - G Kane Jennings
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235-1604, USA.
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5
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Morlock S, Subramanian SK, Zouni A, Lisdat F. Closing the green gap of photosystem I with synthetic fluorophores for enhanced photocurrent generation in photobiocathodes. Chem Sci 2023; 14:1696-1708. [PMID: 36819875 PMCID: PMC9930989 DOI: 10.1039/d2sc05324a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 01/04/2023] [Indexed: 01/18/2023] Open
Abstract
One restriction for biohybrid photovoltaics is the limited conversion of green light by most natural photoactive components. The present study aims to fill the green gap of photosystem I (PSI) with covalently linked fluorophores, ATTO 590 and ATTO 532. Photobiocathodes are prepared by combining a 20 μm thick 3D indium tin oxide (ITO) structure with these constructs to enhance the photocurrent density compared to setups based on native PSI. To this end, two electron transfer mechanisms, with and without a mediator, are studied to evaluate differences in the behavior of the constructs. Wavelength-dependent measurements confirm the influence of the additional fluorophores on the photocurrent. The performance is significantly increased for all modifications compared to native PSI when cytochrome c is present as a redox-mediator. The photocurrent almost doubles from -32.5 to up to -60.9 μA cm-2. For mediator-less photobiocathodes, interestingly, drastic differences appear between the constructs made with various dyes. While the turnover frequency (TOF) is doubled to 10 e-/PSI/s for PSI-ATTO590 on the 3D ITO compared to the reference specimen, the photocurrents are slightly smaller since the PSI-ATTO590 coverage is low. In contrast, the PSI-ATTO532 construct performs exceptionally well. The TOF increases to 31 e-/PSI/s, and a photocurrent of -47.0 μA cm-2 is obtained. This current is a factor of 6 better than the reference made with native PSI in direct electron transfer mode and sets a new record for mediator-free photobioelectrodes combining 3D electrode structures and light-converting biocomponents.
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Affiliation(s)
- Sascha Morlock
- Biosystems Technology, Technical University of Applied Sciences Wildau Hochschulring 1 15745 Wildau Germany .,Biophysics of Photosynthesis, Humboldt University of Berlin Philippstraße 13 10099 Berlin Germany
| | - Senthil K. Subramanian
- Biophysics of Photosynthesis, Humboldt University of BerlinPhilippstraße 1310099 BerlinGermany
| | - Athina Zouni
- Biophysics of Photosynthesis, Humboldt University of BerlinPhilippstraße 1310099 BerlinGermany
| | - Fred Lisdat
- Biosystems Technology, Technical University of Applied Sciences Wildau Hochschulring 1 15745 Wildau Germany
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6
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Cryo-EM structure of the whole photosynthetic reaction center apparatus from the green sulfur bacterium Chlorobaculum tepidum. Proc Natl Acad Sci U S A 2023; 120:e2216734120. [PMID: 36693097 PMCID: PMC9945994 DOI: 10.1073/pnas.2216734120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Light energy absorption and transfer are very important processes in photosynthesis. In green sulfur bacteria light is absorbed primarily by the chlorosomes and its energy is transferred via the Fenna-Matthews-Olson (FMO) proteins to a homodimeric reaction center (RC). Here, we report the cryogenic electron microscopic structure of the intact FMO-RC apparatus from Chlorobaculum tepidum at 2.5 Å resolution. The FMO-RC apparatus presents an asymmetric architecture and contains two FMO trimers that show different interaction patterns with the RC core. Furthermore, the two permanently bound transmembrane subunits PscC, which donate electrons to the special pair, interact only with the two large PscA subunits. This structure fills an important gap in our understanding of the transfer of energy from antenna to the electron transport chain of this RC and the transfer of electrons from reduced sulfur compounds to the special pair.
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7
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Morlock S, Subramanian SK, Zouni A, Lisdat F. Bio-inorganic hybrid structures for direct electron transfer to photosystem I in photobioelectrodes. Biosens Bioelectron 2022; 214:114495. [DOI: 10.1016/j.bios.2022.114495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/31/2022] [Accepted: 06/19/2022] [Indexed: 11/02/2022]
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8
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Keable SM, Kölsch A, Simon PS, Dasgupta M, Chatterjee R, Subramanian SK, Hussein R, Ibrahim M, Kim IS, Bogacz I, Makita H, Pham CC, Fuller FD, Gul S, Paley D, Lassalle L, Sutherlin KD, Bhowmick A, Moriarty NW, Young ID, Blaschke JP, de Lichtenberg C, Chernev P, Cheah MH, Park S, Park G, Kim J, Lee SJ, Park J, Tono K, Owada S, Hunter MS, Batyuk A, Oggenfuss R, Sander M, Zerdane S, Ozerov D, Nass K, Lemke H, Mankowsky R, Brewster AS, Messinger J, Sauter NK, Yachandra VK, Yano J, Zouni A, Kern J. Room temperature XFEL crystallography reveals asymmetry in the vicinity of the two phylloquinones in photosystem I. Sci Rep 2021; 11:21787. [PMID: 34750381 PMCID: PMC8575901 DOI: 10.1038/s41598-021-00236-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 09/02/2021] [Indexed: 11/09/2022] Open
Abstract
Photosystem I (PS I) has a symmetric structure with two highly similar branches of pigments at the center that are involved in electron transfer, but shows very different efficiency along the two branches. We have determined the structure of cyanobacterial PS I at room temperature (RT) using femtosecond X-ray pulses from an X-ray free electron laser (XFEL) that shows a clear expansion of the entire protein complex in the direction of the membrane plane, when compared to previous cryogenic structures. This trend was observed by complementary datasets taken at multiple XFEL beamlines. In the RT structure of PS I, we also observe conformational differences between the two branches in the reaction center around the secondary electron acceptors A1A and A1B. The π-stacked Phe residues are rotated with a more parallel orientation in the A-branch and an almost perpendicular confirmation in the B-branch, and the symmetry breaking PsaB-Trp673 is tilted and further away from A1A. These changes increase the asymmetry between the branches and may provide insights into the preferential directionality of electron transfer.
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Affiliation(s)
- Stephen M Keable
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Adrian Kölsch
- Institut für Biologie, Humboldt-Universität Zu Berlin, 10115, Berlin, Germany
| | - Philipp S Simon
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Medhanjali Dasgupta
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ruchira Chatterjee
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | | | - Rana Hussein
- Institut für Biologie, Humboldt-Universität Zu Berlin, 10115, Berlin, Germany
| | - Mohamed Ibrahim
- Institut für Biologie, Humboldt-Universität Zu Berlin, 10115, Berlin, Germany
| | - In-Sik Kim
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Isabel Bogacz
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hiroki Makita
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Cindy C Pham
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Franklin D Fuller
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Sheraz Gul
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Daniel Paley
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Louise Lassalle
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Kyle D Sutherlin
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Asmit Bhowmick
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Nigel W Moriarty
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Iris D Young
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, 94158, USA
| | - Johannes P Blaschke
- National Energy Research Scientific Computing Center, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Casper de Lichtenberg
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, 75237, Uppsala, Sweden.,Department of Chemistry, Umeå University, Linnaeus väg 6 (KBC huset), 90187, Umeå, Sweden
| | - Petko Chernev
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, 75237, Uppsala, Sweden
| | - Mun Hon Cheah
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, 75237, Uppsala, Sweden
| | - Sehan Park
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, Korea
| | - Gisu Park
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, Korea
| | - Jangwoo Kim
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, Korea
| | - Sang Jae Lee
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, Korea
| | - Jaehyun Park
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, Korea
| | - Kensuke Tono
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan.,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Shigeki Owada
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan.,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Mark S Hunter
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Alexander Batyuk
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | | | | | | | | | - Karol Nass
- Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Henrik Lemke
- Paul Scherrer Institut, 5232, Villigen, Switzerland
| | | | - Aaron S Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Johannes Messinger
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, 75237, Uppsala, Sweden
| | - Nicholas K Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Vittal K Yachandra
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Athina Zouni
- Institut für Biologie, Humboldt-Universität Zu Berlin, 10115, Berlin, Germany
| | - Jan Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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Morlock S, Subramanian SK, Zouni A, Lisdat F. Scalable Three-Dimensional Photobioelectrodes Made of Reduced Graphene Oxide Combined with Photosystem I. ACS APPLIED MATERIALS & INTERFACES 2021; 13:11237-11246. [PMID: 33621059 DOI: 10.1021/acsami.1c01142] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Photobioelectrodes represent one of the examples where artificial materials are combined with biological entities to undertake semi-artificial photosynthesis. Here, an approach is described that uses reduced graphene oxide (rGO) as an electrode material. This classical 2D material is used to construct a three-dimensional structure by a template-based approach combined with a simple spin-coating process during preparation. Inspired by this novel material and photosystem I (PSI), a biophotovoltaic electrode is being designed and investigated. Both direct electron transfer to PSI and mediated electron transfer via cytochrome c from horse heart as redox protein can be confirmed. Electrode preparation and protein immobilization have been optimized. The performance can be upscaled by adjusting the thickness of the 3D electrode using different numbers of spin-coating steps during preparation. Thus, photocurrents up to ∼14 μA/cm2 are measured for 12 spin-coated layers of rGO corresponding to a turnover frequency of 30 e- PSI-1 s-1 and external quantum efficiency (EQE) of 0.07% at a thickness of about 15 μm. Operational stability has been analyzed for several days. Particularly, the performance at low illumination intensities is very promising (1.39 μA/cm2 at 0.1 mW/cm2 and -0.15 V vs Ag/AgCl; EQE 6.8%).
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Affiliation(s)
- Sascha Morlock
- Biosystems Technology, Institute of Life Sciences and Biomedical Technologies, Technical University of Applied Sciences Wildau, Hochschulring 1, Wildau 15745, Germany
- Biophysics of Photosynthesis, Institute for Biology, Humboldt University of Berlin, Philippstraße 13, Berlin 10115, Germany
| | - Senthil K Subramanian
- Biophysics of Photosynthesis, Institute for Biology, Humboldt University of Berlin, Philippstraße 13, Berlin 10115, Germany
| | - Athina Zouni
- Biophysics of Photosynthesis, Institute for Biology, Humboldt University of Berlin, Philippstraße 13, Berlin 10115, Germany
| | - Fred Lisdat
- Biosystems Technology, Institute of Life Sciences and Biomedical Technologies, Technical University of Applied Sciences Wildau, Hochschulring 1, Wildau 15745, Germany
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10
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Insights into Solution Structures of Photosynthetic Protein Complexes from Small-Angle Scattering Methods. CRYSTALS 2021. [DOI: 10.3390/cryst11020203] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
High-resolution structures of photosynthetic pigment–protein complexes are often determined using crystallography or cryo-electron microscopy (cryo-EM), which are restricted to the use of protein crystals or to low temperatures, respectively. However, functional studies and biotechnological applications of photosystems necessitate the use of proteins isolated in aqueous solution, so that the relevance of high-resolution structures has to be independently verified. In this regard, small-angle neutron and X-ray scattering (SANS and SAXS, respectively) can serve as the missing link because of their capability to provide structural information for proteins in aqueous solution at physiological temperatures. In the present review, we discuss the principles and prototypical applications of SANS and SAXS using the photosynthetic pigment–protein complexes phycocyanin (PC) and Photosystem I (PSI) as model systems for a water-soluble and for a membrane protein, respectively. For example, the solution structure of PSI was studied using SAXS and SANS with contrast matching. A Guinier analysis reveals that PSI in solution is virtually free of aggregation and characterized by a radius of gyration of about 75 Å. The latter value is about 10% larger than expected from the crystal structure. This is corroborated by an ab initio structure reconstitution, which also shows a slight expansion of Photosystem I in buffer solution at room temperature. In part, this may be due to conformational states accessible by thermally activated protein dynamics in solution at physiological temperatures. The size of the detergent belt is derived by comparison with SANS measurements without detergent match, revealing a monolayer of detergent molecules under proper solubilization conditions.
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11
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Falke S, Feiler C, Chapman H, Sarrou I. Crystal structures of native cytochrome c 6 from Thermosynechococcus elongatus in two different space groups and implications for its oligomerization. Acta Crystallogr F Struct Biol Commun 2020; 76:444-452. [PMID: 32880593 PMCID: PMC7470040 DOI: 10.1107/s2053230x20010249] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 07/23/2020] [Indexed: 11/10/2022] Open
Abstract
Native cytochrome c6 was purified from an extract of strain BP-1 of the thermophilic cyanobacterium Thermosynechococcus elongatus. The protein was crystallized, and with only slight modifications of the buffer and vapour-diffusion conditions two different space groups were observed, namely H3 and C2. Both crystal structures were solved; they contained three and six molecules per asymmetric unit and were refined to 1.7 and 2.25 Å resolution, respectively. To date, the structure of native cytochrome c6 from T. elongatus has only been reported as a monomer using NMR spectroscopy, i.e. without addressing putative oligomerization, and related structures have only previously been solved using X-ray crystallography after recombinant gene overexpression in Escherichia coli. The reported space groups of related cyanobacterial cytochrome c6 structures differ from those reported here. Interestingly, the protein-protein interfaces that were observed utilizing X-ray crystallography could also explain homo-oligomerization in solution; specifically, trimerization is indicated by infra-red dynamic light scattering and blue native gel electrophoresis in solution. Trimers were also detected by mass spectrometry. Furthermore, there is an indication of post-translational methylation in the crystal structure. Additionally, the possibility of modifying the crystal size and the redox activity in the context of photosynthesis is shaping the investigated cytochrome as a highly suitable model protein for advanced serial crystallography at highly brilliant X-ray free-electron laser sources.
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Affiliation(s)
- Sven Falke
- Institute for Biochemistry and Molecular Biology, University of Hamburg, c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany
| | - Christian Feiler
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Henry Chapman
- Center for Free-Electron Laser Science, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Iosifina Sarrou
- Center for Free-Electron Laser Science, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
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Kölsch A, Radon C, Golub M, Baumert A, Bürger J, Mielke T, Lisdat F, Feoktystov A, Pieper J, Zouni A, Wendler P. Current limits of structural biology: The transient interaction between cytochrome c 6 and photosystem I. Curr Res Struct Biol 2020; 2:171-179. [PMID: 34235477 PMCID: PMC8244401 DOI: 10.1016/j.crstbi.2020.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/11/2020] [Accepted: 08/17/2020] [Indexed: 12/22/2022] Open
Abstract
Trimeric photosystem I from the cyanobacterium Thermosynechococcus elongatus (TePSI) is an intrinsic membrane protein, which converts solar energy into electrical energy by oxidizing the soluble redox mediator cytochrome c 6 (Cyt c 6 ) and reducing ferredoxin. Here, we use cryo-electron microscopy and small angle neutron scattering (SANS) to characterize the transient binding of Cyt c 6 to TePSI. The structure of TePSI cross-linked to Cyt c 6 was solved at a resolution of 2.9 Å and shows additional cofactors as well as side chain density for 84% of the peptide chain of subunit PsaK, revealing a hydrophobic, membrane intrinsic loop that enables binding of associated proteins. Due to the poor binding specificity, Cyt c 6 could not be localized with certainty in our cryo-EM analysis. SANS measurements confirm that Cyt c 6 does not bind to TePSI at protein concentrations comparable to those for cross-linking. However, SANS data indicate a complex formation between TePSI and the non-native mitochondrial cytochrome from horse heart (Cyt c HH ). Our study pinpoints the difficulty of identifying very small binding partners (less than 5% of the overall size) in EM structures when binding affinities are poor. We relate our results to well resolved co-structures with known binding affinities and recommend confirmatory methods for complexes with K M values higher than 20 μM.
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Affiliation(s)
- A. Kölsch
- Department of Biology, Humboldt–Universität zu Berlin, Philippstrasse 13, 10115, Berlin, Germany
| | - C. Radon
- Institute of Biochemistry and Biology, Department of Biochemistry, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Potsdam-Golm, Germany
| | - M. Golub
- Institute of Physics, University of Tartu, Wilhelm Ostwaldi 1, 50411, Tartu, Estonia
| | - A. Baumert
- Institute of Biochemistry and Biology, Department of Biochemistry, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Potsdam-Golm, Germany
| | - J. Bürger
- Max-Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195, Berlin, Germany
- Charité, Institut für Medizinische Physik und Biophysik, Charitéplatz 1, 10117, Berlin, Germany
| | - T. Mielke
- Max-Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195, Berlin, Germany
| | - F. Lisdat
- Institute of Applied Life Sciences, Technical University of Applied Sciences Wildau, Hochschulring 1, 15745, Wildau, Germany
| | - A. Feoktystov
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstr. 1, 85748, Garching, Germany
| | - J. Pieper
- Institute of Physics, University of Tartu, Wilhelm Ostwaldi 1, 50411, Tartu, Estonia
| | - A. Zouni
- Department of Biology, Humboldt–Universität zu Berlin, Philippstrasse 13, 10115, Berlin, Germany
| | - P. Wendler
- Institute of Biochemistry and Biology, Department of Biochemistry, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Potsdam-Golm, Germany
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Wolfe KD, Dervishogullari D, Stachurski CD, Passantino JM, Kane Jennings G, Cliffel DE. Photosystem I Multilayers within Porous Indium Tin Oxide Cathodes Enhance Mediated Electron Transfer. ChemElectroChem 2019. [DOI: 10.1002/celc.201901628] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Kody D. Wolfe
- Interdisciplinary Materials Science Program Vanderbilt University Nashville Tennessee 37235-1822 United States
| | - Dilek Dervishogullari
- Department of Chemistry Vanderbilt University Nashville Tennessee 37235-1822 United States
| | | | - Joshua M. Passantino
- Department of Chemical and Biomolecular Engineering Vanderbilt University Nashville Tennessee 37235-1822 United States
| | - G. Kane Jennings
- Department of Chemical and Biomolecular Engineering Vanderbilt University Nashville Tennessee 37235-1822 United States
| | - David E. Cliffel
- Department of Chemistry Vanderbilt University Nashville Tennessee 37235-1822 United States
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Ciornii D, Kölsch A, Zouni A, Lisdat F. A precursor-approach in constructing 3D ITO electrodes for the improved performance of photosystem I-cyt c photobioelectrodes. NANOSCALE 2019; 11:15862-15870. [PMID: 31380869 DOI: 10.1039/c9nr04344f] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In recent years the use of photoelectrodes based on conductive metal oxides has become very popular in the field of photovoltaics. The application of 3D electrodes holds great promise since they can integrate large amounts of photoactive proteins. In this study photosystem I (PSI) from the thermophilic cyanobacterium Thermosynechococcus elongatus was immobilized on 3D ITO electrodes and electrically wired via the redox protein cytochrome c (cyt c). The main goal, however, was the investigation of construction parameters of such electrodes for achieving a high performance. For this, ITO electrodes were constructed from liquid precursors resulting in improved transmission compared to previous nanoparticle-based preparation protocols. First, the doping level of Sn was varied for establishing suitable conditions for a fast cyt c electrochemistry on such 3D electrodes. In a second step the pore diameter was varied in order to elucidate optimal conditions. Third, the scalability of the template-based preparation was studied from 3 to 15 layers during spin coating and the subsequent baking step. In the thickness range from 3 to 17 μm no limitation in the protein immobilization and also in the photocurrent generation was found. Consequently, a photocurrent of about 270 μA cm-2 and a turnover number (Te) of 30 e- s-1 at PSI were achieved. Because of the high current flow the withdrawal of electrons at the stromal side of PSI becomes clearly rate limiting. Here improved transport conditions and alternative electron acceptors were studied to overcome this limitation.
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Affiliation(s)
- Dmitri Ciornii
- Biosystems Technology, Institute of Life Sciences and Biomedical Technologies, Technical University Wildau, 15745 Wildau, Hochschulring 1, Germany.
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Exploiting new ways for a more efficient orientation and wiring of PSI to electrodes: A fullerene C70 approach. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.01.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Brady NG, Li M, Ma Y, Gumbart JC, Bruce BD. Non-detergent isolation of a cyanobacterial photosystem I using styrene maleic acid alternating copolymers. RSC Adv 2019; 9:31781-31796. [PMID: 35527920 PMCID: PMC9072662 DOI: 10.1039/c9ra04619d] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/02/2019] [Indexed: 11/21/2022] Open
Abstract
Trimeric Photosystem I (PSI) from the thermophilic cyanobacteriumThermosynechococcus elongatus(Te) is the largest membrane protein complex to be encapsulated within a SMALP to date.
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Affiliation(s)
- Nathan G. Brady
- Department of Biochemistry & Cellular and Molecular Biology
- University of Tennessee at Knoxville
- Knoxville
- USA
| | - Meng Li
- Department of Biochemistry & Cellular and Molecular Biology
- University of Tennessee at Knoxville
- Knoxville
- USA
- Bredesen Center for Interdisciplinary Research and Education
| | - Yue Ma
- Department of Biochemistry & Cellular and Molecular Biology
- University of Tennessee at Knoxville
- Knoxville
- USA
| | | | - Barry D. Bruce
- Department of Biochemistry & Cellular and Molecular Biology
- University of Tennessee at Knoxville
- Knoxville
- USA
- Bredesen Center for Interdisciplinary Research and Education
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