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Miloslavina YA, Thomas B, Reus M, Gupta KBSS, Oostergetel GT, Andreas LB, Holzwarth AR, de Groot HJM. Contrasting packing modes for tubular assemblies in chlorosomes. PHOTOSYNTHESIS RESEARCH 2024; 161:105-115. [PMID: 38538911 PMCID: PMC11269348 DOI: 10.1007/s11120-024-01089-3] [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: 10/14/2023] [Accepted: 02/27/2024] [Indexed: 07/25/2024]
Abstract
The largest light-harvesting antenna in nature, the chlorosome, is a heterogeneous helical BChl self-assembly that has evolved in green bacteria to harvest light for performing photosynthesis in low-light environments. Guided by NMR chemical shifts and distance constraints for Chlorobaculum tepidum wild-type chlorosomes, the two contrasting packing modes for syn-anti parallel stacks of BChl c to form polar 2D arrays, with dipole moments adding up, are explored. Layered assemblies were optimized using local orbital density functional and plane wave pseudopotential methods. The packing mode with the lowest energy contains syn-anti and anti-syn H-bonding between stacks. It can accommodate R and S epimers, and side chain variability. For this packing, a match with the available EM data on the subunit axial repeat and optical data is obtained with multiple concentric cylinders for a rolling vector with the stacks running at an angle of 21° to the cylinder axis and with the BChl dipole moments running at an angle ß ∼ 55° to the tube axis, in accordance with optical data. A packing mode involving alternating syn and anti parallel stacks that is at variance with EM appears higher in energy. A weak cross-peak at -6 ppm in the MAS NMR with 50 kHz spinning, assigned to C-181, matches the shift of antiparallel dimers, which possibly reflects a minor impurity-type fraction in the self-assembled BChl c.
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Affiliation(s)
- Yuliya A Miloslavina
- Institute of Chemistry, Leiden University, Box 9502, 2300 RA, Leiden, The Netherlands
- Max-Planck-Institut für Multidisziplinäre Naturwissenschaften, Am Faßberg 11, 37077, Göttingen, Germany
- Eduard-Zintl-Institut für Anorganische and Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str, 64287, Darmstadt, Germany
| | - Brijith Thomas
- Institute of Chemistry, Leiden University, Box 9502, 2300 RA, Leiden, The Netherlands
- Science Division, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Michael Reus
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstr. 34-36, Mülheim a. d. Ruhr, Germany
| | | | - Gert T Oostergetel
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Loren B Andreas
- Max-Planck-Institut für Multidisziplinäre Naturwissenschaften, Am Faßberg 11, 37077, Göttingen, Germany
| | - Alfred R Holzwarth
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstr. 34-36, Mülheim a. d. Ruhr, Germany
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Huub J M de Groot
- Institute of Chemistry, Leiden University, Box 9502, 2300 RA, Leiden, The Netherlands.
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2
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Dsouza L, Li X, Erić V, Huijser A, Jansen TLC, Holzwarth AR, Buda F, Bryant DA, Bahri S, Gupta KBSS, Sevink GJA, de Groot HJM. An integrated approach towards extracting structural characteristics of chlorosomes from a bchQ mutant of Chlorobaculum tepidum. Phys Chem Chem Phys 2024; 26:15856-15867. [PMID: 38546236 DOI: 10.1039/d4cp00221k] [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: 06/07/2024]
Abstract
Chlorosomes, the photosynthetic antenna complexes of green sulfur bacteria, are paradigms for light-harvesting elements in artificial designs, owing to their efficient energy transfer without protein participation. We combined magic angle spinning (MAS) NMR, optical spectroscopy and cryogenic electron microscopy (cryo-EM) to characterize the structure of chlorosomes from a bchQ mutant of Chlorobaculum tepidum. The chlorosomes of this mutant have a more uniform composition of bacteriochlorophyll (BChl) with a predominant homolog, [8Ethyl, 12Ethyl] BChl c, compared to the wild type (WT). Nearly complete 13C chemical shift assignments were obtained from well-resolved homonuclear 13C-13C RFDR data. For proton assignments heteronuclear 13C-1H (hCH) data sets were collected at 1.2 GHz spinning at 60 kHz. The CHHC experiments revealed intermolecular correlations between 132/31, 132/32, and 121/31, with distance constraints of less than 5 Å. These constraints indicate the syn-anti parallel stacking motif for the aggregates. Fourier transform cryo-EM data reveal an axial repeat of 1.49 nm for the helical tubular aggregates, perpendicular to the inter-tube separation of 2.1 nm. This axial repeat is different from WT and is in line with BChl syn-anti stacks running essentially parallel to the tube axis. Such a packing mode is in agreement with the signature of the Qy band in circular dichroism (CD). Combining the experimental data with computational insight suggests that the packing for the light-harvesting function is similar between WT and bchQ, while the chirality within the chlorosomes is modestly but detectably affected by the reduced compositional heterogeneity in bchQ.
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Affiliation(s)
- Lolita Dsouza
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA, Leiden, The Netherlands.
| | - Xinmeng Li
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA, Leiden, The Netherlands.
- Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, 0315, Oslo, Norway
| | - Vesna Erić
- Zernike Institute of Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, The Netherlands
| | - Annemarie Huijser
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE, The Netherlands
| | - Thomas L C Jansen
- Zernike Institute of Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, The Netherlands
| | - Alfred R Holzwarth
- Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Francesco Buda
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA, Leiden, The Netherlands.
| | - Donald A Bryant
- Department for Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Salima Bahri
- NMR Spectroscopy, Bijvoet center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | | | - G J Agur Sevink
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA, Leiden, The Netherlands.
| | - Huub J M de Groot
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA, Leiden, The Netherlands.
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3
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Frehan SK, Dsouza L, Li X, Eríc V, Jansen TLC, Mul G, Holzwarth AR, Buda F, Sevink GJA, de Groot HJM, Huijser A. Photon Energy-Dependent Ultrafast Exciton Transfer in Chlorosomes of Chlorobium tepidum and the Role of Supramolecular Dynamics. J Phys Chem B 2023; 127:7581-7589. [PMID: 37611240 PMCID: PMC10493955 DOI: 10.1021/acs.jpcb.3c05282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/09/2023] [Indexed: 08/25/2023]
Abstract
The antenna complex of green sulfur bacteria, the chlorosome, is one of the most efficient supramolecular systems for efficient long-range exciton transfer in nature. Femtosecond transient absorption experiments provide new insight into how vibrationally induced quantum overlap between exciton states supports highly efficient long-range exciton transfer in the chlorosome of Chlorobium tepidum. Our work shows that excitation energy is delocalized over the chlorosome in <1 ps at room temperature. The following exciton transfer to the baseplate occurs in ∼3 to 5 ps, in line with earlier work also performed at room temperature, but significantly faster than at the cryogenic temperatures used in previous studies. This difference can be attributed to the increased vibrational motion at room temperature. We observe a so far unknown impact of the excitation photon energy on the efficiency of this process. This dependency can be assigned to distinct optical domains due to structural disorder, combined with an exciton trapping channel competing with exciton transfer toward the baseplate. An oscillatory transient signal damped in <1 ps has the highest intensity in the case of the most efficient exciton transfer to the baseplate. These results agree well with an earlier computational finding of exciton transfer driven by low-frequency rotational motion of molecules in the chlorosome. Such an exciton transfer process belongs to the quantum coherent regime, for which the Förster theory for intermolecular exciton transfer does not apply. Our work hence strongly indicates that structural flexibility is important for efficient long-range exciton transfer in chlorosomes.
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Affiliation(s)
- Sean K. Frehan
- MESA+
Institute for Nanotechnology, University
of Twente, 7500 AE Enschede, The Netherlands
| | - Lolita Dsouza
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - Xinmeng Li
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
- Department
of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, 0315 Oslo, Norway
| | - Vesna Eríc
- Zernike
Institute of Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Thomas L. C. Jansen
- Zernike
Institute of Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Guido Mul
- MESA+
Institute for Nanotechnology, University
of Twente, 7500 AE Enschede, The Netherlands
| | - Alfred R. Holzwarth
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Francesco Buda
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - G. J. Agur Sevink
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - Huub J. M. de Groot
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - Annemarie Huijser
- MESA+
Institute for Nanotechnology, University
of Twente, 7500 AE Enschede, The Netherlands
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4
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Erić V, Li X, Dsouza L, Frehan SK, Huijser A, Holzwarth AR, Buda F, Sevink GJA, de Groot HJM, Jansen TLC. Manifestation of Hydrogen Bonding and Exciton Delocalization on the Absorption and Two-Dimensional Electronic Spectra of Chlorosomes. J Phys Chem B 2023; 127:1097-1109. [PMID: 36696537 PMCID: PMC9923760 DOI: 10.1021/acs.jpcb.2c07143] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Chlorosomes are supramolecular aggregates that contain thousands of bacteriochlorophyll molecules. They perform the most efficient ultrafast excitation energy transfer of all natural light-harvesting complexes. Their broad absorption band optimizes light capture. In this study, we identify the microscopic sources of the disorder causing the spectral width and reveal how it affects the excited state properties and the optical response of the system. We combine molecular dynamics, quantum chemical calculations, and response function calculations to achieve this goal. The predicted linear and two-dimensional electronic spectra are found to compare well with experimental data reproducing all key spectral features. Our analysis of the microscopic model reveals the interplay of static and dynamic disorder from the molecular perspective. We find that hydrogen bonding motifs are essential for a correct description of the spectral line shape. Furthermore, we find that exciton delocalization over tens to hundreds of molecules is consistent with the two-dimensional electronic spectra.
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Affiliation(s)
- Vesna Erić
- University
of Groningen, Zernike Institute
for Advanced Materials, 9747
AG Groningen, The Netherlands
| | - Xinmeng Li
- Department
of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, Sem Sælands vei 26, 0315 Oslo, Norway
| | - Lolita Dsouza
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - Sean K. Frehan
- MESA+
Institute for Nanotechnology, University
of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands
| | - Annemarie Huijser
- MESA+
Institute for Nanotechnology, University
of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands
| | - Alfred R. Holzwarth
- Department
of Biophysical Chemistry, Max Planck Institute
for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim, Germany
| | - Francesco Buda
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - G. J. Agur Sevink
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - Huub J. M. de Groot
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - Thomas L. C. Jansen
- University
of Groningen, Zernike Institute
for Advanced Materials, 9747
AG Groningen, The Netherlands,
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5
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Kunsel T, Günther LM, Köhler J, Jansen TLC, Knoester J. Probing size variations of molecular aggregates inside chlorosomes using single-object spectroscopy. J Chem Phys 2021; 155:124310. [PMID: 34598584 DOI: 10.1063/5.0061529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We theoretically investigate the possibility to use single-object spectroscopy to probe size variations of the bacteriochlorophyll aggregates inside chlorosomes. Chlorosomes are the light-harvesting organelles of green sulfur and non-sulfur bacteria. They are known to be the most efficient light-harvesting systems in nature. Key to this efficiency is the organization of bacteriochlorophyll molecules in large self-assembled aggregates that define the secondary structure inside the chlorosomes. Many studies have been reported to elucidate the morphology of these aggregates and the molecular packing inside them. It is widely believed that tubular aggregates play an important role. Because the size (radius and length) of these aggregates affects the optical and excitation energy transport properties, it is of interest to be able to probe these quantities inside chlorosomes. We show that a combination of single-chlorosome linear polarization resolved spectroscopy and single-chlorosome circular dichroism spectroscopy may be used to access the typical size of the tubular aggregates within a chlorosome and, thus, probe possible variations between individual chlorosomes that may result, for instance, from different stages in growth or different growth conditions.
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Affiliation(s)
- T Kunsel
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - L M Günther
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, D-95440 Bayreuth, Germany
| | - J Köhler
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, D-95440 Bayreuth, Germany
| | - T L C Jansen
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - J Knoester
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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6
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Günther LM, Knoester J, Köhler J. Limitations of Linear Dichroism Spectroscopy for Elucidating Structural Issues of Light-Harvesting Aggregates in Chlorosomes. Molecules 2021; 26:899. [PMID: 33572047 PMCID: PMC7914687 DOI: 10.3390/molecules26040899] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/26/2021] [Accepted: 02/02/2021] [Indexed: 11/17/2022] Open
Abstract
Linear dichroism (LD) spectroscopy is a widely used technique for studying the mutual orientation of the transition-dipole moments of the electronically excited states of molecular aggregates. Often the method is applied to aggregates where detailed information about the geometrical arrangement of the monomers is lacking. However, for complex molecular assemblies where the monomers are assembled hierarchically in tiers of supramolecular structural elements, the method cannot extract well-founded information about the monomer arrangement. Here we discuss this difficulty on the example of chlorosomes, which are the light-harvesting aggregates of photosynthetic green-(non) sulfur bacteria. Chlorosomes consist of hundreds of thousands of bacteriochlorophyll molecules that self-assemble into secondary structural elements of curved lamellar or cylindrical morphology. We exploit data from polarization-resolved fluorescence-excitation spectroscopy performed on single chlorosomes for reconstructing the corresponding LD spectra. This reveals that LD spectroscopy is not suited for benchmarking structural models in particular for complex hierarchically organized molecular supramolecular assemblies.
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Affiliation(s)
- Lisa M. Günther
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany;
| | - Jasper Knoester
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands;
| | - Jürgen Köhler
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany;
- Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
- Bavarian Polymer Institute, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
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7
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Silori Y, Chawla S, De AK. Unravelling the Role of Water in Ultrafast Excited-State Relaxation Dynamics within Nano-Architectures of Chlorophyll a. Chemphyschem 2020; 21:1908-1917. [PMID: 32619067 DOI: 10.1002/cphc.202000487] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/01/2020] [Indexed: 11/06/2022]
Abstract
Water plays a pivotal role in structural stability of supramolecular pigment assemblies designed for natural light harvesting (for example, chlorosome antenna complex) as well as their artificial analogs. However, the dynamic role of water in the context of excite-state relaxation has not been explored till date, which we report here. Using femtosecond transient absorption spectroscopy, we investigate the excited-state dynamics of two types of nano-scale assemblies of chlorophyll a with different structural motifs, rod-shaped and micellar assemblies, that depend on the water content. We show how water participates in excess energy dissipation by vibrational cooling of the non-thermally populated Qy band at different rates in different types of clusters but exhibits no polar solvation dynamics. For the micelles, we observe a bifurcation of stimulated emission line shape, whereas a positive-to-negative switching of differential absorption is observed for the rods; both these observations are correlated with their specific structural aspects. Density functional theory calculations reveal two possible stable ground state geometries of dimers, accounting for the bifurcation of line shape in micelles. Thus, our study elucidates water-mediated structure-function relationship within these pigment assemblies.
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Affiliation(s)
- Yogita Silori
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab, 140 306, India
| | - Sakshi Chawla
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab, 140 306, India
| | - Arijit K De
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab, 140 306, India
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8
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Abstract
Modified tetrapyrroles are large macrocyclic compounds, consisting of diverse conjugation and metal chelation systems and imparting an array of colors to the biological structures that contain them. Tetrapyrroles represent some of the most complex small molecules synthesized by cells and are involved in many essential processes that are fundamental to life on Earth, including photosynthesis, respiration, and catalysis. These molecules are all derived from a common template through a series of enzyme-mediated transformations that alter the oxidation state of the macrocycle and also modify its size, its side-chain composition, and the nature of the centrally chelated metal ion. The different modified tetrapyrroles include chlorophylls, hemes, siroheme, corrins (including vitamin B12), coenzyme F430, heme d1, and bilins. After nearly a century of study, almost all of the more than 90 different enzymes that synthesize this family of compounds are now known, and expression of reconstructed operons in heterologous hosts has confirmed that most pathways are complete. Aside from the highly diverse nature of the chemical reactions catalyzed, an interesting aspect of comparative biochemistry is to see how different enzymes and even entire pathways have evolved to perform alternative chemical reactions to produce the same end products in the presence and absence of oxygen. Although there is still much to learn, our current understanding of tetrapyrrole biogenesis represents a remarkable biochemical milestone that is summarized in this review.
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Affiliation(s)
- Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, United Kingdom
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9
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Li X, Buda F, de Groot HJ, Sevink GJA. Contrasting Modes of Self-Assembly and Hydrogen-Bonding Heterogeneity in Chlorosomes of Chlorobaculum tepidum. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2018; 122:14877-14888. [PMID: 30258522 PMCID: PMC6150686 DOI: 10.1021/acs.jpcc.8b01790] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/30/2018] [Indexed: 06/08/2023]
Abstract
Chlorosome antennae form an interesting class of materials for studying the role of structural motifs and dynamics in nonadiabatic energy transfer. They perform robust and highly quantum-efficient transfer of excitonic energy while allowing for compositional variation and completely lacking the usual regulatory proteins. Here, we first cast the geometrical analysis for ideal tubular scaffolding models into a formal framework, to relate effective helical properties of the assembly structures to established characterization data for various types of chlorosomes. This analysis shows that helicity is uniquely defined for chlorosomes composed of bacteriochlorophyll (BChl) d and that three chiral angles are consistent with the nuclear magnetic resonance (NMR) and electron microscope data for BChl c, including two novel ones that are at variance with current interpretations of optical data based on perfect cylindrical symmetry. We use this information as a starting point for investigating dynamic and static heterogeneity at the molecular level by unconstrained molecular dynamics. We first identify a rotational degree of freedom, along the Mg-OH coordination bond, that alternates along the syn-anti stacks and underlies the (flexible) curvature on a larger scale. Because rotation directly relates to the formation or breaking of interstack hydrogen bonds of the O-H···O=C structural motif along the syn-anti stacks, we analyzed the relative fractions of hydrogen-bonded and the nonbonded regions, forming stripe domains in otherwise spectroscopically homogeneous curved slabs. The ratios 7:3 for BChl c and 9:1 for BChl d for the two distinct structural components agree well with the signal intensities determined by NMR. In addition, rotation with curvature-independent formation of stripe domains offers a viable explanation for the localization and dispersion of exciton states over two fractions, as observed in single chlorosome fluorescence decay studies.
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10
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Günther LM, Löhner A, Reiher C, Kunsel T, Jansen TLC, Tank M, Bryant DA, Knoester J, Köhler J. Structural Variations in Chlorosomes from Wild-Type and a bchQR Mutant of Chlorobaculum tepidum Revealed by Single-Molecule Spectroscopy. J Phys Chem B 2018; 122:6712-6723. [PMID: 29863357 DOI: 10.1021/acs.jpcb.8b02875] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Green sulfur bacteria can grow photosynthetically by absorbing only a few photons per bacteriochlorophyll molecule per day. They contain chlorosomes, perhaps the most efficient light-harvesting antenna system found in photosynthetic organisms. Chlorosomes contain supramolecular structures comprising hundreds of thousands of bacteriochlorophyll molecules, which are properly positioned with respect to one another solely by self-assembly and not by using a protein scaffold as a template for directing the mutual arrangement of the monomers. These two features-high efficiency and self-assembly-have attracted considerable attention for developing light-harvesting systems for artificial photosynthesis. However, reflecting the heterogeneity of the natural system, detailed structural information at atomic resolution of the molecular aggregates is not yet available. Here, we compare the results for chlorosomes from the wild type and two mutants of Chlorobaculum tepidum obtained by polarization-resolved, single-particle fluorescence-excitation spectroscopy and theoretical modeling with results previously obtained from nuclear-magnetic resonance spectroscopy and cryo-electron microscopy. Only the combination of information obtained from all of these techniques allows for an unambiguous description of the molecular packing of bacteriochlorophylls within chlorosomes. In contrast to some suggestions in the literature, we find that, for the chlorosomes from the wild type as well as for those from mutants, the dominant secondary structural element features tubular symmetry following a very similar construction principle. Moreover, the results suggest that the various options for methylation of the bacteriochlorophyll molecules, which are a primary source of the structural (and spectral) heterogeneity of wild-type chlorosome samples, are exploited by nature to achieve improved spectral coverage at the level of individual chlorosomes.
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Affiliation(s)
| | | | | | - Tenzin Kunsel
- Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Thomas L C Jansen
- Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Marcus Tank
- Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , State College , Pennsylvania 16802 , United States
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , State College , Pennsylvania 16802 , United States.,Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Jasper Knoester
- Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
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11
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Shoji S, Ogawa T, Hashishin T, Tamiaki H. Self-Assemblies of Zinc Bacteriochlorophyll-d Analogues Having Amide, Ester, and Urea Groups as Substituents at 17-Position and Observation of Lamellar Supramolecular Nanostructures. Chemphyschem 2018; 19:913-920. [PMID: 29231276 DOI: 10.1002/cphc.201701044] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/07/2017] [Indexed: 11/05/2022]
Abstract
Chlorosomes are unique light-harvesting apparatuses in photosynthetic green bacteria. Single chlorosomes contain a large number of bacteriochlorophyll (BChl)-c, -d, -e, and -f molecules, which self-assemble without protein assistance. These BChl self-assemblies involving specific intermolecular interactions (Mg⋅⋅⋅O32 -H⋅⋅⋅O=C131 and π-π stacks of chlorin skeletons) in a chlorosome have been reported to be round-shaped rods (or tubes) with diameters of 5 or 10 nm, or lamellae with a layer spacing of approximately 2 nm. Herein, the self-assembly of synthetic zinc BChl-d analogues having ester, amide, and urea groups in the 17-substituent is reported. Spectroscopic analyses indicate that the zinc BChl-d analogues self-assemble in a nonpolar organic solvent in a similar manner to natural chlorosomal BChls with additional assistance by hydrogen-bonding of secondary amide (or urea) groups (CON-H⋅⋅⋅O=CNH). Microscopic analyses of the supramolecules of a zinc BChl-d analogue bearing amide and urea groups show round- or square-shaped rods with widths of about 65 nm. Cryogenic TEM shows a lamellar arrangement of the zinc chlorin with a layer spacing of 1.5 nm inside the rod. Similar thick rods are also visible in the micrographs of self-assemblies of zinc BChl-d analogues with one or two secondary amide moieties in the 17-substituent.
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Affiliation(s)
- Sunao Shoji
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Tetsuya Ogawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Takeshi Hashishin
- Faculty of Engineering, Kumamoto University, Kumamoto, Kumamoto, 860-8555, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
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12
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Saga Y, Yamashita H. Effects of exogenous isoprenoid diphosphates on in vivo attachment to bacteriochlorophyllide c in the green sulfur photosynthetic bacterium Chlorobaculum tepidum. J Biosci Bioeng 2017; 124:408-413. [PMID: 28579086 DOI: 10.1016/j.jbiosc.2017.05.004] [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: 03/25/2017] [Revised: 04/22/2017] [Accepted: 05/08/2017] [Indexed: 11/18/2022]
Abstract
Metabolic substitution of the esterifying chain in bacteriochlorophyll (BChl) c in green photosynthetic bacteria grown by supplementation of exogenous alcohols has attracted attentions to study supramolecular structures and biogenesis of major antenna complexes chlorosomes in these bacteria as well as BChl pigment biosynthesis. Actual substrates in the enzymatic attachment of the esterifying moieties to the precursor of BChl c, namely bacteriochlorophyllide (BChlide) c, in these bacteria are believed to be diphosphate esters of alcoholic substrates, although only intact alcohols have so far been supplemented in the bacterial cultures. We report herein BChl c compositions in the green sulfur photosynthetic bacterium Chlorobaculum tepidum by supplementation with geranyl and geranylgeranyl diphosphates. The supplementation of these diphosphates hardly produced BChl c derivatives esterified with geraniol and geranylgeraniol in Cba. tepidum, whereas these BChl c derivatives were accumulated by supplementation of intact geraniol and geranylgeraniol. The sharp contrast of the incorporation efficiency of the supplemental isoprenoid moieties in BChl c using the isoprenoid diphosphates to that by the isoprenoid alcohols was mainly ascribable to less penetration abilities of the diphosphate substrates into Cba. tepidum cells because of their anionic and polar diphosphate moiety.
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Affiliation(s)
- Yoshitaka Saga
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
| | - Hayato Yamashita
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan
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13
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Two-dimensional electronic spectra of the photosynthetic apparatus of green sulfur bacteria. Sci Rep 2017; 7:45245. [PMID: 28345621 PMCID: PMC5366913 DOI: 10.1038/srep45245] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 02/21/2017] [Indexed: 12/25/2022] Open
Abstract
Advances in time resolved spectroscopy have provided new insight into the energy transmission in natural photosynthetic complexes. Novel theoretical tools and models are being developed in order to explain the experimental results. We provide a model calculation for the two-dimensional electronic spectra of Cholorobaculum tepidum which correctly describes the main features and transfer time scales found in recent experiments. From our calculation one can infer the coupling of the antenna chlorosome with the environment and the coupling between the chlorosome and the Fenna-Matthews-Olson complex. We show that environment assisted transport between the subunits is the required mechanism to reproduce the experimental two-dimensional electronic spectra.
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14
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Shoji S, Mizoguchi T, Tamiaki H. In vitro self-assemblies of bacteriochlorophylls-c from Chlorobaculum tepidum and their supramolecular nanostructures. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2015.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Shoji S, Ogawa T, Hashishin T, Ogasawara S, Watanabe H, Usami H, Tamiaki H. Nanotubes of Biomimetic Supramolecules Constructed by Synthetic Metal Chlorophyll Derivatives. NANO LETTERS 2016; 16:3650-3654. [PMID: 27172060 DOI: 10.1021/acs.nanolett.6b00781] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Various supramolecular nanotubes have recently been built up by lipids, peptides, and other organic molecules. Major light-harvesting (LH) antenna systems in a filamentous anoxygenic phototroph, Chloroflexus (Cfl.) aurantiacus, are called chlorosomes and contain photofunctional single-wall supramolecular nanotubes with approximately 5 nm in their diameter. Chlorosomal supramolecular nanotubes of Cfl. aurantiacus are constructed by a large amount of bacteriochlorophyll(BChl)-c molecules. Such a pigment self-assembles in a chlorosome without any assistance from the peptides, which is in sharp contrast to the other natural photosynthetic LH antennas. To mimic chlorosomal supramolecular nanotubes, synthetic models were prepared by the modification of naturally occurring chlorophyll(Chl)-a molecule. Metal complexes (magnesium, zinc, and cadmium) of the Chl derivative were synthesized as models of natural chlorosomal BChls. These metal Chl derivatives self-assembled in hydrophobic environments, and their supramolecules were analyzed by spectroscopic and microscopic techniques. Cryo-transmission electron microscopic images showed that the zinc and cadmium Chl derivatives could form single-wall supramolecular nanotubes and their outer and inner diameters were approximately 5 and 3 nm, respectively. Atomic force microscopic images suggested that the magnesium Chl derivative formed similar nanotubes to those of the corresponding zinc and cadmium complexes. Three chlorosomal single-wall supramolecular nanotubes of the metal Chl derivatives were prepared in the solid state and would be useful as photofunctional materials.
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Affiliation(s)
- Sunao Shoji
- Graduate School of Life Sciences, Ritsumeikan University , Kusatsu, Shiga 525-8577, Japan
| | - Tetsuya Ogawa
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Takeshi Hashishin
- Faculty of Engineering, Kumamoto University , Kumamoto, Kumamoto 860-8555, Japan
| | - Shin Ogasawara
- Graduate School of Life Sciences, Ritsumeikan University , Kusatsu, Shiga 525-8577, Japan
| | - Hiroaki Watanabe
- Graduate School of Life Sciences, Ritsumeikan University , Kusatsu, Shiga 525-8577, Japan
| | - Hisanao Usami
- Faculty of Textile Science and Technology, Shinshu University , Ueda, Nagano 386-8567, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University , Kusatsu, Shiga 525-8577, Japan
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Somoza Márquez A, Chen L, Sun K, Zhao Y. Probing ultrafast excitation energy transfer of the chlorosome with exciton–phonon variational dynamics. Phys Chem Chem Phys 2016; 18:20298-311. [DOI: 10.1039/c5cp06491k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Excitation energy transfer of the chlorosome is investigated using exciton–phonon variational dynamics revealing ultrafast energy relaxation and exciton delocalization on a 100 fs scale.
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Affiliation(s)
| | - Lipeng Chen
- Division of Materials Science
- Nanyang Technological University
- Singapore 639798
- Singapore
| | - Kewei Sun
- School of Science
- Hangzhou Dianzi University
- Hangzhou 310018
- China
| | - Yang Zhao
- Division of Materials Science
- Nanyang Technological University
- Singapore 639798
- Singapore
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17
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Harada J, Teramura M, Mizoguchi T, Tsukatani Y, Yamamoto K, Tamiaki H. Stereochemical conversion of C3-vinyl group to 1-hydroxyethyl group in bacteriochlorophyll c by the hydratases BchF and BchV: adaptation of green sulfur bacteria to limited-light environments. Mol Microbiol 2015; 98:1184-98. [PMID: 26331578 DOI: 10.1111/mmi.13208] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2015] [Indexed: 11/28/2022]
Abstract
Photosynthetic green sulfur bacteria inhabit anaerobic environments with very low-light conditions. To adapt to such environments, these bacteria have evolved efficient light-harvesting antenna complexes called as chlorosomes, which comprise self-aggregated bacteriochlorophyll c in the model green sulfur, bacterium Chlorobaculum tepidum. The pigment possess a hydroxy group at the C3(1) position that produces a chiral center with R- or S-stereochemistry and the C3(1) -hydroxy group serves as a connecting moiety for the self-aggregation. Chlorobaculum tepidum carries the two possible homologous genes for C3-vinyl hydratase, bchF and bchV. In the present study, we constructed deletion mutants of each of these genes. Pigment analyses of the bchF-inactivated mutant, which still has BchV as a sole hydratase, showed higher ratios of S-epimeric bacteriochlorophyll c than the wild-type strain. The heightened prevalence of S-stereoisomers in the mutant was more remarkable at lower light intensities and caused a red shift of the chlorosomal Qy absorption band leading to advantages for light-energy transfer. In contrast, the bchV-mutant possessing only BchF showed a significant decrease of the S-epimers and accumulations of C3-vinyl BChl c species. As trans- criptional level of bchV was upregulated at lower light intensity, the Chlorobaculum tepidum adapted to low-light environments by control of the bchV transcription.
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Affiliation(s)
- Jiro Harada
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume, Fukuoka, 830-0011, Japan
| | - Misato Teramura
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Tadashi Mizoguchi
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Yusuke Tsukatani
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo, 152-8550, Japan.,PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, 332-0012, Japan
| | - Ken Yamamoto
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume, Fukuoka, 830-0011, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
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18
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Lange C, Kiesel S, Peters S, Virus S, Scheer H, Jahn D, Moser J. Broadened Substrate Specificity of 3-Hydroxyethyl Bacteriochlorophyllide a Dehydrogenase (BchC) Indicates a New Route for the Biosynthesis of Bacteriochlorophyll a. J Biol Chem 2015; 290:19697-709. [PMID: 26088139 PMCID: PMC4528133 DOI: 10.1074/jbc.m115.660555] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/18/2015] [Indexed: 11/06/2022] Open
Abstract
Bacteriochlorophyll a biosynthesis requires formation of a 3-hydroxyethyl group on pyrrole ring A that gets subsequently converted into a 3-acetyl group by 3-vinyl bacteriochlorophyllide a hydratase (BchF) followed by 3-hydroxyethyl bacteriochlorophyllide a dehydrogenase (BchC). Heterologous overproduction of Chlorobaculum tepidum BchF revealed an integral transmembrane protein that was efficiently isolated by detergent solubilization. Recombinant C. tepidum BchC was purified as a soluble protein-NAD(+) complex. Substrate recognition of BchC was investigated using six artificial substrate molecules. Modification of the isocyclic E ring, omission of the central magnesium ion, zinc as an alternative metal ion, and a non-reduced B ring system were tolerated by BchC. According to this broadened in vitro activity, the chlorin 3-hydroxyethyl chlorophyllide a was newly identified as a natural substrate of BchC in a reconstituted pathway consisting of dark-operative protochlorophyllide oxidoreductase, BchF, and BchC. The established reaction sequence would allow for an additional new branching point for the synthesis of bacteriochlorophyll a. Biochemical and site-directed mutagenesis analyses revealed, in contrast to theoretical predictions, a zinc-independent BchC catalysis that requires NAD(+) as a cofactor. Based on these results, we are designating a new medium-chain dehydrogenase/reductase family (MDR057 BchC) as theoretically proposed from a recent bioinformatics analysis.
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Affiliation(s)
- Christiane Lange
- From the Institute of Microbiology, Technische Universität Braunschweig, Spielmannstrasse 7, D-38106 Braunschweig, Germany and
| | - Svenja Kiesel
- From the Institute of Microbiology, Technische Universität Braunschweig, Spielmannstrasse 7, D-38106 Braunschweig, Germany and
| | - Sabine Peters
- From the Institute of Microbiology, Technische Universität Braunschweig, Spielmannstrasse 7, D-38106 Braunschweig, Germany and
| | - Simone Virus
- From the Institute of Microbiology, Technische Universität Braunschweig, Spielmannstrasse 7, D-38106 Braunschweig, Germany and
| | - Hugo Scheer
- Department Biology I, Botany, Ludwig-Maximilians-Universität München, Menzingerstrasse 67, D-80638 München, Germany
| | - Dieter Jahn
- From the Institute of Microbiology, Technische Universität Braunschweig, Spielmannstrasse 7, D-38106 Braunschweig, Germany and
| | - Jürgen Moser
- From the Institute of Microbiology, Technische Universität Braunschweig, Spielmannstrasse 7, D-38106 Braunschweig, Germany and
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19
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Sun J, Hu Y, Li W, Zhang Y, Chen J, Deng F. Sequential decolorization of azo dye and mineralization of decolorization liquid coupled with bioelectricity generation using a pH self-neutralized photobioelectrochemical system operated with polarity reversion. JOURNAL OF HAZARDOUS MATERIALS 2015; 289:108-117. [PMID: 25723885 DOI: 10.1016/j.jhazmat.2015.02.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/20/2015] [Accepted: 02/03/2015] [Indexed: 05/06/2023]
Abstract
A novel photobioelectrochemical system (PBES) was developed by acclimating algal-bacterial biofilm in both anode and cathode using Chlorella vulgaris and indigenous wastewater bacteria as inoculums. The PBES was operated in polarity reversion mode depend on dark/light alternate reaction to achieve simultaneous pH self-neutralization, azo dye degradation (Congo red) and bioelectricity generation. The anodic accumulated acidity and cathodic accumulated alkalinity were self-neutralized after polarity reversion and hence eliminate the membrane pH gradient. The Congo red was first decolored in the dark anode and the resultant decolorization liquid was subsequently mineralized after the dark anode changing to the photo-biocathode. The presence of C. vulgaris significantly enhanced the two-stage degradation of Congo red, with 93% increases in decolorization rates and 8% increases in mineralization compared to the algae-free BES. The PBES continuously generated stable voltage output over four months under repeatedly reversion of polarity. The maximum power density produced before and after polarity reversion was 78 and 61 mW/m(2), respectively. The synergy between C. vulgaris and mixed bacteria was responsible for the successful operation of the PBES which can be potentially applied to treat wastewater containing azo dye with benefits of enhanced azo dye degradation, high net power output and buffer minimization.
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Affiliation(s)
- Jian Sun
- Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China; School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Yongyou Hu
- Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China; State Key Lab of Pulp and Paper Engineering, College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640, China.
| | - Wanjun Li
- Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Yaping Zhang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Jie Chen
- Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Feng Deng
- Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
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20
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Sawaya NPD, Huh J, Fujita T, Saikin SK, Aspuru-Guzik A. Fast delocalization leads to robust long-range excitonic transfer in a large quantum chlorosome model. NANO LETTERS 2015; 15:1722-1729. [PMID: 25694170 DOI: 10.1021/nl504399d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chlorosomes are efficient light-harvesting antennas containing up to hundreds of thousands of bacteriochlorophyll molecules. With massively parallel computer hardware, we use a nonperturbative stochastic Schrödinger equation, while including an atomistically derived spectral density, to study excitonic energy transfer in a realistically sized chlorosome model. We find that fast short-range delocalization leads to robust long-range transfer due to the antennae's concentric-roll structure. Additionally, we discover anomalous behavior arising from different initial conditions, and outline general considerations for simulating excitonic systems on the nanometer to micrometer scale.
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Affiliation(s)
- Nicolas P D Sawaya
- Department of Chemistry and Chemical Biology, Harvard University , 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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21
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Grouzdev DS, Kuznetsov BB, Keppen OI, Krasil’nikova EN, Lebedeva NV, Ivanovsky RN. Reconstruction of bacteriochlorophyll biosynthesis pathways in the filamentous anoxygenic phototrophic bacterium Oscillochloris trichoides DG-6 and evolution of anoxygenic phototrophs of the order Chloroflexales. Microbiology (Reading) 2015; 161:120-130. [DOI: 10.1099/mic.0.082313-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Denis S. Grouzdev
- Faculty of Biology, Moscow State University, Moscow, Russia
- Bioengineering Center, Russian Academy of Sciences, Moscow, Russia
| | | | - Olga I. Keppen
- Faculty of Biology, Moscow State University, Moscow, Russia
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22
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Strong coupling between chlorosomes of photosynthetic bacteria and a confined optical cavity mode. Nat Commun 2014; 5:5561. [PMID: 25429787 DOI: 10.1038/ncomms6561] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 10/14/2014] [Indexed: 01/13/2023] Open
Abstract
Strong exciton-photon coupling is the result of a reversible exchange of energy between an excited state and a confined optical field. This results in the formation of polariton states that have energies different from the exciton and photon. We demonstrate strong exciton-photon coupling between light-harvesting complexes and a confined optical mode within a metallic optical microcavity. The energetic anti-crossing between the exciton and photon dispersions characteristic of strong coupling is observed in reflectivity and transmission with a Rabi splitting energy on the order of 150 meV, which corresponds to about 1,000 chlorosomes coherently coupled to the cavity mode. We believe that the strong coupling regime presents an opportunity to modify the energy transfer pathways within photosynthetic organisms without modification of the molecular structure.
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23
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Luo SC, Khin Y, Huang SJ, Yang Y, Hou TY, Cheng YC, Chen HM, Chin YY, Chen CT, Lin HJ, Tang JKH, Chan JCC. Probing the Spatial Organization of Bacteriochlorophyll c by Solid-State Nuclear Magnetic Resonance. Biochemistry 2014; 53:5515-25. [DOI: 10.1021/bi500755r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | - Yadana Khin
- Department
of Chemistry and Biochemistry, Clark University, Worcester, Massachusetts 01610, United States,
| | | | - Yanshen Yang
- Department
of Chemistry and Biochemistry, Clark University, Worcester, Massachusetts 01610, United States,
| | | | | | | | - Yi-Ying Chin
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chien-Te Chen
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Hong-Ji Lin
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Joseph Kuo-Hsiang Tang
- Department
of Chemistry and Biochemistry, Clark University, Worcester, Massachusetts 01610, United States,
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24
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v Berlepsch H, Ludwig K, Schade B, Haag R, Böttcher C. Progress in the direct structural characterization of fibrous amphiphilic supramolecular assemblies in solution by transmission electron microscopic techniques. Adv Colloid Interface Sci 2014; 208:279-92. [PMID: 24508499 DOI: 10.1016/j.cis.2014.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/09/2014] [Accepted: 01/11/2014] [Indexed: 11/28/2022]
Abstract
The self-assembly of amphiphilic molecules into fibrous structures has been the subject of numerous studies over past decades due to various current and promising technical applications. Although very different in their head group chemistry many natural as well as synthetic amphiphilic compounds derived from carbohydrates, carbocyanine dyes, or amino acids tend to form fibrous structures by molecular self-assembly in water predominantly twisted ribbons or tubes. Often a transition between these assembly structures is observed, which is a phenomenon already theoretically approached by Wolfgang Helfrich and still focus point in current research. With the development of suitable sample preparation and electron optical imaging techniques, cryogenic transmission electron microscopy (cryo-TEM) in combination with three-dimensional (3D) reconstruction techniques has become a particular popular direct characterization technique for supramolecular assemblies in general. Here we review the recent progress in deriving precise structural information from cryo-TEM data of particularly fibrous structures preferably in three dimensions.
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Affiliation(s)
- Hans v Berlepsch
- Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany; Core Facility BioSupraMol an der Freien Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany
| | - Kai Ludwig
- Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany
| | - Boris Schade
- Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany
| | - Rainer Haag
- Core Facility BioSupraMol an der Freien Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany; Institut für Chemie und Biochemie - Organische Chemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany
| | - Christoph Böttcher
- Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 36a, 14195 Berlin, Germany.
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25
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Fujita T, Huh J, Saikin SK, Brookes JC, Aspuru-Guzik A. Theoretical characterization of excitation energy transfer in chlorosome light-harvesting antennae from green sulfur bacteria. PHOTOSYNTHESIS RESEARCH 2014; 120:273-289. [PMID: 24504540 DOI: 10.1007/s11120-014-9978-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 01/23/2014] [Indexed: 06/03/2023]
Abstract
We present a theoretical study of excitation dynamics in the chlorosome antenna complex of green photosynthetic bacteria based on a recently proposed model for the molecular assembly. Our model for the excitation energy transfer (EET) throughout the antenna combines a stochastic time propagation of the excitonic wave function with molecular dynamics simulations of the supramolecular structure and electronic structure calculations of the excited states. We characterized the optical properties of the chlorosome with absorption, circular dichroism and fluorescence polarization anisotropy decay spectra. The simulation results for the excitation dynamics reveal a detailed picture of the EET in the chlorosome. Coherent energy transfer is significant only for the first 50 fs after the initial excitation, and the wavelike motion of the exciton is completely damped at 100 fs. Characteristic time constants of incoherent energy transfer, subsequently, vary from 1 ps to several tens of ps. We assign the time scales of the EET to specific physical processes by comparing our results with the data obtained from time-resolved spectroscopy experiments.
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Affiliation(s)
- Takatoshi Fujita
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA,
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26
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Valleau S, Saikin SK, Ansari-Oghol-Beig D, Rostami M, Mossallaei H, Aspuru-Guzik A. Electromagnetic study of the chlorosome antenna complex of Chlorobium tepidum. ACS NANO 2014; 8:3884-3894. [PMID: 24641680 DOI: 10.1021/nn500759k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Green sulfur bacteria are an iconic example of nature's adaptation: thriving in environments of extremely low photon density, the bacterium ranks itself among the most efficient natural light-harvesting organisms. The photosynthetic antenna complex of this bacterium is a self-assembled nanostructure, ≈60 × 150 nm, made of bacteriochlorophyll molecules. We study the system from a computational nanoscience perspective by using electrodynamic modeling with the goal of understanding its role as a nanoantenna. Three different nanostructures, built from two molecular packing moieties, are considered: a structure built of concentric cylinders of aggregated bacteriochlorophyll d monomers, a single cylinder of bacteriochlorophyll c monomers, and a model for the entire chlorosome. The theoretical model captures both coherent and incoherent components of exciton transfer. The model is employed to extract optical spectra, concentration and depolarization of electromagnetic fields within the chlorosome, and fluxes of energy transfer for the structures. The second model nanostructure shows the largest field enhancement. Further, field enhancement is found to be more sensitive to dynamic noise rather than structural disorder. Field depolarization, however, is similar for all structures. This indicates that the directionality of transfer is robust to structural variations, while on the other hand, the intensity of transfer can be tuned by structural variations.
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Affiliation(s)
- Stéphanie Valleau
- Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States
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27
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Tang JKH, Saikin SK, Pingali SV, Enriquez MM, Huh J, Frank HA, Urban VS, Aspuru-Guzik A. Temperature and carbon assimilation regulate the chlorosome biogenesis in green sulfur bacteria. Biophys J 2014; 105:1346-56. [PMID: 24047985 DOI: 10.1016/j.bpj.2013.07.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 07/19/2013] [Accepted: 07/23/2013] [Indexed: 11/16/2022] Open
Abstract
Green photosynthetic bacteria adjust the structure and functionality of the chlorosome-the light-absorbing antenna complex-in response to environmental stress factors. The chlorosome is a natural self-assembled aggregate of bacteriochlorophyll (BChl) molecules. In this study, we report the regulation of the biogenesis of the Chlorobaculum tepidum chlorosome by carbon assimilation in conjunction with temperature changes. Our studies indicate that the carbon source and thermal stress culture of C. tepidum grows slower and incorporates fewer BChl c in the chlorosome. Compared with the chlorosome from other cultural conditions we investigated, the chlorosome from the carbon source and thermal stress culture displays (a) smaller cross-sectional radius and overall size, (b) simplified BChl c homologs with smaller side chains, (c) blue-shifted Qy absorption maxima, and (d) a sigmoid-shaped circular dichroism spectra. Using a theoretical model, we analyze how the observed spectral modifications can be associated with structural changes of BChl aggregates inside the chlorosome. Our report suggests a mechanism of metabolic regulation for chlorosome biogenesis.
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Miloslavina Y, Gupta KBSS, Tank M, Bryant DA, de Groot HJM. wPMLG-5 Spectroscopy of Self-Aggregated BChlein Natural Chlorosomes ofChlorobaculum Limnaeum. Isr J Chem 2014. [DOI: 10.1002/ijch.201300129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Huh J, Saikin SK, Brookes JC, Valleau S, Fujita T, Aspuru-Guzik A. Atomistic study of energy funneling in the light-harvesting complex of green sulfur bacteria. J Am Chem Soc 2014; 136:2048-57. [PMID: 24405318 DOI: 10.1021/ja412035q] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Phototrophic organisms such as plants, photosynthetic bacteria, and algae use microscopic complexes of pigment molecules to absorb sunlight. Within the light-harvesting complexes, which frequently have several functional and structural subunits, the energy is transferred in the form of molecular excitations with very high efficiency. Green sulfur bacteria are considered to be among the most efficient light-harvesting organisms. Despite multiple experimental and theoretical studies of these bacteria, the physical origin of the efficient and robust energy transfer in their light-harvesting complexes is not well understood. To study excitation dynamics at the systems level, we introduce an atomistic model that mimics a complete light-harvesting apparatus of green sulfur bacteria. The model contains approximately 4000 pigment molecules and comprises a double wall roll for the chlorosome, a baseplate, and six Fenna-Matthews-Olson trimer complexes. We show that the fast relaxation within functional subunits combined with the transfer between collective excited states of pigments can result in robust energy funneling to the initial excitation conditions and temperature changes. Moreover, the same mechanism describes the coexistence of multiple time scales of excitation dynamics frequently observed in ultrafast optical experiments. While our findings support the hypothesis of supertransfer, the model reveals energy transport through multiple channels on different length scales.
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Affiliation(s)
- Joonsuk Huh
- Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States
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Saga Y, Saiki T, Takahashi N, Shibata Y, Tamiaki H. Scrambled Self-Assembly of Bacteriochlorophyllscandein Aqueous Triton X-100 Micelles. Photochem Photobiol 2013; 90:552-9. [DOI: 10.1111/php.12219] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Accepted: 11/28/2013] [Indexed: 01/13/2023]
Affiliation(s)
- Yoshitaka Saga
- Department of Chemistry; Faculty of Science and Engineering; Kinki University; Higashi-Osaka Japan
| | - Tatsuya Saiki
- Department of Chemistry; Faculty of Science and Engineering; Kinki University; Higashi-Osaka Japan
| | - Naoya Takahashi
- Department of Chemistry; Faculty of Science and Engineering; Kinki University; Higashi-Osaka Japan
| | - Yutaka Shibata
- Department of Chemistry; Graduate School of Science; Tohoku University; Sendai Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences; Ritsumeikan University; Kusatsu Japan
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Sengupta S, Würthner F. Chlorophyll J-aggregates: from bioinspired dye stacks to nanotubes, liquid crystals, and biosupramolecular electronics. Acc Chem Res 2013; 46:2498-512. [PMID: 23865851 DOI: 10.1021/ar400017u] [Citation(s) in RCA: 165] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Among the natural light-harvesting (LH) systems, those of green sulfur and nonsulfur photosynthetic bacteria are exceptional because they lack the support of a protein matrix. Instead, these so-called chlorosomes are based solely on "pigments". These are self-assembled bacteriochlorophyll c, d, and e derivatives, which consist of a chlorophyll skeleton bearing a 3(1)-hydroxy functional group. Chemists consider the latter as an essential structural unit to direct the formation of light-harvesting self-assembled dye aggregates with J-type excitonic coupling. The intriguing properties of chlorosomal J-type aggregates, particularly narrow red-shifted absorption bands, compared with monomers and their ability to delocalize and migrate excitons, have inspired intense research activities toward synthetic analogues in this field. The ultimate goal of this research field is the development of (opto-)electronic devices based on the architectural principle of chlorosomal LH systems. In this regard, the challenge is to develop small, functional building blocks with appropriate substituents that are preprogrammed to self-assemble across different length scales and to emulate functions of natural LH systems or to realize entirely new functions beyond those found in nature. In this Account, we highlight our achievements in the past decade with semisynthetic zinc chlorins (ZnChls) as model compounds of bacteriochlorophylls obtained from the naturally most abundant chlorin precursor: chlorophyll a. To begin, we explore how supramolecular strategies involving π-stacking, hydrogen bonding, and metal-oxygen coordination can be used to design ZnChl-based molecular stack, tube, and liquid crystalline assemblies conducive to charge and energy transport. Our design principle is based on the bioinspired functionalization of the 3(1)-position of ZnChl with a hydroxy or methoxy group; the former gives rise to tubular assemblies, whereas the latter induces stack assemblies. Functionalization of the 17(2)-position with esterified hydrophilic or hydrophobic chains, dendron-wedge substituents, and chromophores having complementary optical properties such as naphthalene bisimides (NBIs) is used to modulate the self-assembly of ZnChl dyes. The resulting assemblies exhibit enhanced charge transport and energy transfer abilities. We have used UV/vis, circular dichroism (CD), fluorescence spectroscopy, and dynamic light scattering (DLS) for the characterization of these assemblies in solution. In addition, we have studied assembly morphologies by atomic force microscopy (AFM), scanning tunneling microscopy (STM), transmission electron microscopy (TEM), and cryogenic-TEM. Crystallographic techniques such as powder X-ray and solid-state NMR have been used to explain the precise long- and short-range packing of dyes in these assemblies. Finally, functional properties such as charge and energy transport have been explored by pulse radiolysis time-resolved microwave conductivity (PR-TRMC), conductive AFM, and time-resolved fluorescence spectroscopy. The design principles discussed in this Account are important steps toward the utilization of these materials in biosupramolecular electronics and photonics in the future.
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Affiliation(s)
- Sanchita Sengupta
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Frank Würthner
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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Sasaki SI, Mizutani K, Kunieda M, Tamiaki H. Cycloaddition to a C3-ethynylated chlorophyll derivative and self-aggregation of zinc chlorin–pyrazole/triazole conjugates. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Orf GS, Blankenship RE. Chlorosome antenna complexes from green photosynthetic bacteria. PHOTOSYNTHESIS RESEARCH 2013; 116:315-31. [PMID: 23761131 DOI: 10.1007/s11120-013-9869-3] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 06/06/2013] [Indexed: 05/18/2023]
Abstract
Chlorosomes are the distinguishing light-harvesting antenna complexes that are found in green photosynthetic bacteria. They contain bacteriochlorophyll (BChl) c, d, e in natural organisms, and recently through mutation, BChl f, as their principal light-harvesting pigments. In chlorosomes, these pigments self-assemble into large supramolecular structures that are enclosed inside a lipid monolayer to form an ellipsoid. The pigment assembly is dictated mostly by pigment-pigment interactions as opposed to protein-pigment interactions. On the bottom face of the chlorosome, the CsmA protein aggregates into a paracrystalline baseplate with BChl a, and serves as the interface to the next energy acceptor in the system. The exceptional light-harvesting ability at very low light conditions of chlorosomes has made them an attractive subject of study for both basic and applied science. This review, incorporating recent advancements, considers several important aspects of chlorosomes: pigment biosynthesis, organization of pigments and proteins, spectroscopic properties, and applications to bio-hybrid and bio-inspired devices.
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Affiliation(s)
- Gregory S Orf
- Departments of Chemistry and Biology, Washington University in St. Louis, Campus Box 1137, One Brookings Drive, St. Louis, MO, 63130, USA
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34
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Reconstruction of rod self-aggregates of natural bacteriochlorophylls-c from Chloroflexus aurantiacus. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.06.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Alia A, Buda F, de Groot HJ, Matysik J. Solid-State NMR of Nanomachines Involved in Photosynthetic Energy Conversion. Annu Rev Biophys 2013; 42:675-99. [DOI: 10.1146/annurev-biophys-083012-130415] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magic-angle spinning NMR, often in combination with photo-CIDNP, is applied to determine how photosynthetic antennae and reaction centers are activated in the ground state to perform their biological function upon excitation by light. Molecular modeling resolves molecular mechanisms by way of computational integration of NMR data with other structure-function analyses. By taking evolutionary historical contingency into account, a better biophysical understanding is achieved. Chlorophyll cofactors and proteins go through self-assembly trajectories that are engineered during evolution and lead to highly homogeneous protein complexes optimized for exciton or charge transfer. Histidine-cofactor interactions allow biological nanomachines to lower energy barriers for light harvesting and charge separation in photosynthetic energy conversion. In contrast, in primordial chlorophyll antenna aggregates, excessive heterogeneity is paired with much less specific characteristics, and both exciton and charge-transfer character are encoded in the ground state.
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Affiliation(s)
- A. Alia
- Solid State NMR, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RB, The Netherlands;, , ,
| | - Francesco Buda
- Solid State NMR, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RB, The Netherlands;, , ,
| | - Huub J.M. de Groot
- Solid State NMR, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RB, The Netherlands;, , ,
| | - Jörg Matysik
- Solid State NMR, Leiden Institute of Chemistry, Leiden University, Leiden 2300 RB, The Netherlands;, , ,
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Pandit A, Ocakoglu K, Buda F, van Marle T, Holzwarth AR, de Groot HJM. Structure Determination of a Bio-Inspired Self-Assembled Light-Harvesting Antenna by Solid-State NMR and Molecular Modeling. J Phys Chem B 2013; 117:11292-8. [DOI: 10.1021/jp402210x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Anjali Pandit
- Leiden Institute of Chemistry, Leiden University, 2300 RA, Leiden, The Netherlands
| | - Kasim Ocakoglu
- Max-Planck-Institute for Chemical Energy Conversion (MPI-CEC) (previously
known as Max-Planck-Institute for Bioinorganic Chemistry), Stiftstrasse
34−36, D-45470 Mülheim an der Ruhr, Germany
| | - Francesco Buda
- Leiden Institute of Chemistry, Leiden University, 2300 RA, Leiden, The Netherlands
| | - Thomas van Marle
- Leiden Institute of Chemistry, Leiden University, 2300 RA, Leiden, The Netherlands
| | - Alfred R. Holzwarth
- Max-Planck-Institute for Chemical Energy Conversion (MPI-CEC) (previously
known as Max-Planck-Institute for Bioinorganic Chemistry), Stiftstrasse
34−36, D-45470 Mülheim an der Ruhr, Germany
| | - Huub J. M. de Groot
- Leiden Institute of Chemistry, Leiden University, 2300 RA, Leiden, The Netherlands
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Orf GS, Tank M, Vogl K, Niedzwiedzki DM, Bryant DA, Blankenship RE. Spectroscopic insights into the decreased efficiency of chlorosomes containing bacteriochlorophyll f. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:493-501. [DOI: 10.1016/j.bbabio.2013.01.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/08/2013] [Accepted: 01/15/2013] [Indexed: 11/24/2022]
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Li H, Frigaard NU, Bryant DA. [2Fe-2S] Proteins in Chlorosomes: CsmI and CsmJ Participate in Light-Dependent Control of Energy Transfer in Chlorosomes of Chlorobaculum tepidum. Biochemistry 2013; 52:1321-30. [DOI: 10.1021/bi301454g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hui Li
- Department of Biochemistry and
Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Niels-Ulrik Frigaard
- Department of Biochemistry and
Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Donald A. Bryant
- Department of Biochemistry and
Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemistry and
Biochemistry, Montana State University,
Bozeman, Montana 59717, United States
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Johnson TW, Li H, Frigaard NU, Golbeck JH, Bryant DA. [2Fe-2S] proteins in Chlorosomes: redox properties of CsmI, CsmJ, and CsmX of the Chlorosome envelope of Chlorobaculum tepidum. Biochemistry 2013; 52:1331-43. [PMID: 23368794 DOI: 10.1021/bi301455k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chlorosome envelope of Chlorobaculum tepidum contains 10 polypeptides, three of which, CsmI, CsmJ, and CsmX, have an adrenodoxin-like domain harboring a single [2Fe-2S] cluster. Mutants that produced chlorosomes containing two, one, or none of these Fe-S proteins were constructed [Li, H., et al. (2013) Biochemistry 52, preceding paper in this issue ( DOI: 10.1021/bi301454g )]. The electron paramagnetic resonance (EPR) spectra, g values, and line widths of the Fe-S clusters in individual CsmI, CsmJ, and CsmX proteins were obtained from studies with isolated chlorosomes. The Fe-S clusters in these proteins were characterized by EPR and could be differentiated on the basis of their g values and line widths. The EPR spectrum of wild-type chlorosomes could be simulated by a 1:1 admixture of the CsmI and CsmJ spectra. No contribution of CsmX to the EPR spectrum of chlorosomes was observed because of its low abundance. In chlorosomes that contained only CsmI or CsmJ, the midpoint potential of the [2Fe-2S] clusters was -205 or 8 mV, respectively; the midpoint potential of the [2Fe-2S] cluster in CsmX was estimated to be more oxidizing than -180 mV. In wild-type chlorosomes, the midpoint potentials of the [2Fe-2S] clusters were -348 mV for CsmI and 92 mV for CsmJ. The lower potential for CsmI in the presence of CsmJ, and the higher potential for CsmJ in the presence of CsmI, were attributed to interactions that occur when these proteins form complexes in the chlorosome envelope. The redox properties of CsmI and CsmJ are consistent with their proposed participation in the transfer of electrons to and from quenchers of energy transfer in chlorosomes.
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Affiliation(s)
- T Wade Johnson
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Furumaki S, Yabiku Y, Habuchi S, Tsukatani Y, Bryant DA, Vacha M. Circular Dichroism Measured on Single Chlorosomal Light-Harvesting Complexes of Green Photosynthetic Bacteria. J Phys Chem Lett 2012; 3:3545-3549. [PMID: 26290985 DOI: 10.1021/jz301671p] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report results on circular dichroism (CD) measured on single immobilized chlorosomes of a triple mutant of green sulfur bacterium Chlorobaculum tepidum . The CD signal is measured by monitoring chlorosomal bacteriochlorphyll c fluorescence excited by alternate left and right circularly polarized laser light with a fixed wavelength of 733 nm. The excitation wavelength is close to a maximum of the negative CD signal of a bulk solution of the same chlorosomes. The average CD dissymmetry parameter obtained from an ensemble of individual chlorosomes was gs = -0.025, with an intrinsic standard deviation (due to variations between individual chlorosomes) of 0.006. The dissymmetry value is about 2.5 times larger than that obtained at the same wavelength in the bulk solution. The difference can be satisfactorily explained by taking into account the orientation factor in the single-chlorosome experiments. The observed distribution of the dissymmetry parameter reflects the well-ordered nature of the mutant chlorosomes.
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Affiliation(s)
- Shu Furumaki
- †Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama 2-12-1-S8, Meguro-ku, Tokyo 152-8552, Japan
| | - Yu Yabiku
- †Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama 2-12-1-S8, Meguro-ku, Tokyo 152-8552, Japan
| | - Satoshi Habuchi
- ‡Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Yusuke Tsukatani
- §Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Donald A Bryant
- §Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- ¶Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Martin Vacha
- †Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama 2-12-1-S8, Meguro-ku, Tokyo 152-8552, Japan
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Vogl K, Tank M, Orf GS, Blankenship RE, Bryant DA. Bacteriochlorophyll f: properties of chlorosomes containing the "forbidden chlorophyll". Front Microbiol 2012; 3:298. [PMID: 22908012 PMCID: PMC3415949 DOI: 10.3389/fmicb.2012.00298] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 07/25/2012] [Indexed: 11/13/2022] Open
Abstract
The chlorosomes of green sulfur bacteria (GSB) are mainly assembled from one of three types of bacteriochlorophylls (BChls), BChls c, d, and e. By analogy to the relationship between BChl c and BChl d (20-desmethyl-BChl c), a fourth type of BChl, BChl f (20-desmethyl-BChl e), should exist but has not yet been observed in nature. The bchU gene (bacteriochlorophyllide C-20 methyltransferase) of the brown-colored green sulfur bacterium Chlorobaculum limnaeum was inactivated by conjugative transfer from Eshcerichia coli and homologous recombination of a suicide plasmid carrying a portion of the bchU. The resulting bchU mutant was greenish brown in color and synthesized BChl f(F). The chlorosomes of the bchU mutant had similar size and polypeptide composition as those of the wild type (WT), but the Q(y) absorption band of the BChl f aggregates was blue-shifted 16 nm (705 nm vs. 721 nm for the WT). Fluorescence spectroscopy showed that energy transfer to the baseplate was much less efficient in chlorosomes containing BChl f than in WT chlorosomes containing BChl e. When cells were grown at high irradiance with tungsten or fluorescent light, the WT and bchU mutant had identical growth rates. However, the WT grew about 40% faster than the bchU mutant at low irradiance (10 μmol photons m(-2) s(-1)). Less efficient energy transfer from BChl f aggregates to BChl a in the baseplate, the much slower growth of the strain producing BChl f relative to the WT, and competition from other phototrophs, may explain why BChl f is not observed naturally.
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Affiliation(s)
- Kajetan Vogl
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park PA, USA
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