1
|
Puskar R, Du Truong C, Swain K, Chowdhury S, Chan KY, Li S, Cheng KW, Wang TY, Poh YP, Mazor Y, Liu H, Chou TF, Nannenga BL, Chiu PL. Molecular asymmetry of a photosynthetic supercomplex from green sulfur bacteria. Nat Commun 2022; 13:5824. [PMID: 36192412 PMCID: PMC9529944 DOI: 10.1038/s41467-022-33505-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/20/2022] [Indexed: 11/21/2022] Open
Abstract
The photochemical reaction center (RC) features a dimeric architecture for charge separation across the membrane. In green sulfur bacteria (GSB), the trimeric Fenna-Matthews-Olson (FMO) complex mediates the transfer of light energy from the chlorosome antenna complex to the RC. Here we determine the structure of the photosynthetic supercomplex from the GSB Chlorobaculum tepidum using single-particle cryogenic electron microscopy (cryo-EM) and identify the cytochrome c subunit (PscC), two accessory protein subunits (PscE and PscF), a second FMO trimeric complex, and a linker pigment between FMO and the RC core. The protein subunits that are assembled with the symmetric RC core generate an asymmetric photosynthetic supercomplex. One linker bacteriochlorophyll (BChl) is located in one of the two FMO-PscA interfaces, leading to differential efficiencies of the two energy transfer branches. The two FMO trimeric complexes establish two different binding interfaces with the RC cytoplasmic surface, driven by the associated accessory subunits. This structure of the GSB photosynthetic supercomplex provides mechanistic insight into the light excitation energy transfer routes and a possible evolutionary transition intermediate of the bacterial photosynthetic supercomplex from the primitive homodimeric RC.
Collapse
Affiliation(s)
- Ryan Puskar
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Chloe Du Truong
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
- Rampart Bioscience, Monrovia, CA, 91016, USA
| | - Kyle Swain
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, 85287, USA
| | - Saborni Chowdhury
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Ka-Yi Chan
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Shan Li
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Kai-Wen Cheng
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Ting Yu Wang
- Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Yu-Ping Poh
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
- Center for Mechanisms of Evolution, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Yuval Mazor
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Haijun Liu
- Department of Biology, Washington University, St. Louis, MO, 63130, USA
| | - Tsui-Fen Chou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
- Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Brent L Nannenga
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, 85287, USA
| | - Po-Lin Chiu
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA.
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.
| |
Collapse
|
2
|
Greening C, Lithgow T. Formation and function of bacterial organelles. Nat Rev Microbiol 2020; 18:677-689. [PMID: 32710089 DOI: 10.1038/s41579-020-0413-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2020] [Indexed: 01/28/2023]
Abstract
Advances in imaging technologies have revealed that many bacteria possess organelles with a proteomically defined lumen and a macromolecular boundary. Some are bound by a lipid bilayer (such as thylakoids, magnetosomes and anammoxosomes), whereas others are defined by a lipid monolayer (such as lipid bodies), a proteinaceous coat (such as carboxysomes) or have a phase-defined boundary (such as nucleolus-like compartments). These diverse organelles have various metabolic and physiological functions, facilitating adaptation to different environments and driving the evolution of cellular complexity. This Review highlights that, despite the diversity of reported organelles, some unifying concepts underlie their formation, structure and function. Bacteria have fundamental mechanisms of organelle formation, through which conserved processes can form distinct organelles in different species depending on the proteins recruited to the luminal space and the boundary of the organelle. These complex subcellular compartments provide evolutionary advantages as well as enabling metabolic specialization, biogeochemical processes and biotechnological advances. Growing evidence suggests that the presence of organelles is the rule, rather than the exception, in bacterial cells.
Collapse
Affiliation(s)
- Chris Greening
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia.
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia.
| |
Collapse
|
3
|
Shen G, Canniffe DP, Ho MY, Kurashov V, van der Est A, Golbeck JH, Bryant DA. Characterization of chlorophyll f synthase heterologously produced in Synechococcus sp. PCC 7002. PHOTOSYNTHESIS RESEARCH 2019; 140:77-92. [PMID: 30607859 DOI: 10.1007/s11120-018-00610-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/17/2018] [Indexed: 05/19/2023]
Abstract
In diverse terrestrial cyanobacteria, Far-Red Light Photoacclimation (FaRLiP) promotes extensive remodeling of the photosynthetic apparatus, including photosystems (PS)I and PSII and the cores of phycobilisomes, and is accompanied by the concomitant biosynthesis of chlorophyll (Chl) d and Chl f. Chl f synthase, encoded by chlF, is a highly divergent paralog of psbA; heterologous expression of chlF from Chlorogloeopsis fritscii PCC 9212 led to the light-dependent production of Chl f in Synechococcus sp. PCC 7002 (Ho et al., Science 353, aaf9178 (2016)). In the studies reported here, expression of the chlF gene from Fischerella thermalis PCC 7521 in the heterologous system led to enhanced synthesis of Chl f. N-terminally [His]10-tagged ChlF7521 was purified and identified by immunoblotting and tryptic-peptide mass fingerprinting. As predicted from its sequence similarity to PsbA, ChlF bound Chl a and pheophytin a at a ratio of ~ 3-4:1, bound β-carotene and zeaxanthin, and was inhibited in vivo by 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Cross-linking studies and the absence of copurifying proteins indicated that ChlF forms homodimers. Flash photolysis of ChlF produced a Chl a triplet that decayed with a lifetime (1/e) of ~ 817 µs and that could be attributed to intersystem crossing by EPR spectroscopy at 90 K. When the chlF7521 gene was expressed in a strain in which the psbD1 and psbD2 genes had been deleted, significantly more Chl f was produced, and Chl f levels could be further enhanced by specific growth-light conditions. Chl f synthesized in Synechococcus sp. PCC 7002 was inserted into trimeric PSI complexes.
Collapse
Affiliation(s)
- Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Daniel P Canniffe
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
| | - Ming-Yang Ho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Vasily Kurashov
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Art van der Est
- Department of Chemistry, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA.
- S-002 Frear Laboratory, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
| |
Collapse
|
4
|
Magdaong NCM, Niedzwiedzki DM, Saer RG, Goodson C, Blankenship RE. Excitation energy transfer kinetics and efficiency in phototrophic green sulfur bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1180-1190. [DOI: 10.1016/j.bbabio.2018.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/25/2018] [Accepted: 07/30/2018] [Indexed: 01/16/2023]
|
5
|
Saga Y, Yoshida N, Yamada S, Mizoguchi T, Tamiaki H. Biosynthesis of unnatural glycolipids possessing diyne moiety in the acyl chain in the green sulfur photosynthetic bacterium Chlorobaculum tepidum grown by supplementation of 10,12-heptadecadiynic acid. Biochem Biophys Rep 2017; 9:42-46. [PMID: 28955987 PMCID: PMC5614547 DOI: 10.1016/j.bbrep.2016.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/09/2016] [Accepted: 11/12/2016] [Indexed: 12/04/2022] Open
Abstract
Unnatural glycolipids possessing the diyne moiety in their acyl groups were successfully biosynthesized in the green sulfur photosynthetic bacterium Chlorobaculum (Cba.) tepidum by cultivation with supplementation of 10,12-heptadecadiynic acid. Monogalactosyldiacylglycerol (MGDG) and rhamnosylgalactosyldiacylglycerol (RGDG) esterified with one 10,12-heptadecadiynic acid were primarily formed in the cells, and small amounts of glycolipids esterified with the two unnatural fatty acids can also be detected. The relative ratio of these unnatural glycolipids occupied in the total glycolipids was estimated to be 49% based on HPLC analysis using a evaporative light scattering detector. These results indicate that the acyl groups in glycolipids, which play important roles in the formation of extramembranous antenna complexes called chlorosomes, can be modified in vivo by cultivation of green sulfur photosynthetic bacteria with exogenous synthetic fatty acids. Visible absorption and circular dichroism spectra of Cba. tepidum containing the unnatural glycolipids demonstrated the formation of chlorosomes, indicating that the unnatural glycolipids in this study did not interfere with the biogenesis of chlorosomes. Novel glycolipids possessing a diyne moiety in the acyl chain were biosynthesized. Supplemental fatty acids were used in the biosynthesis of glycolipids in the photosynthetic bacterium. The novel glycolipids did not inhibit the formation of photosynthetic antenna complexes.
Collapse
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
| | - Nozomi Yoshida
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Shota Yamada
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Tadashi Mizoguchi
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| |
Collapse
|
6
|
Genome Sequence of Prosthecochloris sp. Strain CIB 2401 of the Phylum Chlorobi. GENOME ANNOUNCEMENTS 2016; 4:4/6/e01222-16. [PMID: 27811102 PMCID: PMC5095472 DOI: 10.1128/genomea.01222-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To date, only 13 genomes of green sulfur bacteria (family Chlorobiaceae) have been sequenced. The sequenced strains do not cover the full phylogenetic diversity of the family. We determined the complete genome sequence of Prosthecochloris sp. strain CIB 2401, thereby increasing the genome information for the poorly represented marine Chlorobiaceae.
Collapse
|
7
|
In situ high-resolution structure of the baseplate antenna complex in Chlorobaculum tepidum. Nat Commun 2016; 7:12454. [PMID: 27534696 PMCID: PMC4992139 DOI: 10.1038/ncomms12454] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 07/05/2016] [Indexed: 01/01/2023] Open
Abstract
Photosynthetic antenna systems enable organisms harvesting light and transfer the energy to the photosynthetic reaction centre, where the conversion to chemical energy takes place. One of the most complex antenna systems, the chlorosome, found in the photosynthetic green sulfur bacterium Chlorobaculum (Cba.) tepidum contains a baseplate, which is a scaffolding super-structure, formed by the protein CsmA and bacteriochlorophyll a. Here we present the first high-resolution structure of the CsmA baseplate using intact fully functional, light-harvesting organelles from Cba. tepidum, following a hybrid approach combining five complementary methods: solid-state NMR spectroscopy, cryo-electron microscopy, isotropic and anisotropic circular dichroism and linear dichroism. The structure calculation was facilitated through development of new software, GASyCS for efficient geometry optimization of highly symmetric oligomeric structures. We show that the baseplate is composed of rods of repeated dimers of the strongly amphipathic CsmA with pigments sandwiched within the dimer at the hydrophobic side of the helix. The chlorosome of the photosynthetic bacterium C. tepidum harvests light and transfers the energy to the photosynthetic reaction centre. Here the authors determine the structure of the baseplate, a scaffolding super-structure, to show that the baseplate consists of rods of repeated CsmA dimers containing pigment molecules.
Collapse
|
8
|
Tsukatani Y, Mizoguchi T, Thweatt J, Tank M, Bryant DA, Tamiaki H. Glycolipid analyses of light-harvesting chlorosomes from envelope protein mutants of Chlorobaculum tepidum. PHOTOSYNTHESIS RESEARCH 2016; 128:235-241. [PMID: 26869354 DOI: 10.1007/s11120-016-0228-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/25/2016] [Indexed: 06/05/2023]
Abstract
Chlorosomes are large and efficient light-harvesting organelles in green photosynthetic bacteria, and they characteristically contain large numbers of bacteriochlorophyll c, d, or e molecules. Self-aggregated bacteriochlorophyll pigments are surrounded by a monolayer envelope membrane comprised of glycolipids and Csm proteins. Here, we analyzed glycolipid compositions of chlorosomes from the green sulfur bacterium Chlorobaculum tepidum mutants lacking one, two, or three Csm proteins by HPLC equipped with an evaporative light-scattering detector. The ratio of monogalactosyldiacylglyceride (MGDG) to rhamnosylgalactosyldiacylglyceride (RGDG) was smaller in chlorosomes from mutants lacking two or three proteins in CsmC/D/H motif family than in chlorosomes from the wild-type, whereas chlorosomes lacking CsmIJ showed relatively less RGDG than MGDG. The results suggest that the CsmC, CsmD, CsmH, and other chlorosome proteins are involved in organizing MGDG and RGDG and thereby affect the size and shape of the chlorosome.
Collapse
Affiliation(s)
- Yusuke Tsukatani
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8550, Japan.
- PRESTO, Japan Science and Technology Agency, Saitama, 332-0012, Japan.
| | - Tadashi Mizoguchi
- Graduate School of Life Sciences, Ritsumeikan University, Shiga, 525-8577, Japan
| | - Jennifer Thweatt
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Pennsylvania, 16802, USA
| | - Marcus Tank
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Pennsylvania, 16802, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Pennsylvania, 16802, USA
- Department of Chemistry and Biochemistry, Montana State University, Montana, 59717, USA
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Shiga, 525-8577, Japan
| |
Collapse
|
9
|
Adachi K, Watanabe K, Yamazaki S. pH-Responsive Switchable Aggregation Phenomena of Xanthene Dyes Adsorbed on Tungsten(VI) Oxide Colloid Surface. Ind Eng Chem Res 2014. [DOI: 10.1021/ie5018817] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Kenta Adachi
- Department of Environmental Science & Engineering, Graduate School of Science & Engineering, Yamaguchi University, Yamaguchi, 753-8512, Japan
| | - Kohei Watanabe
- Department of Environmental Science & Engineering, Graduate School of Science & Engineering, Yamaguchi University, Yamaguchi, 753-8512, Japan
| | - Suzuko Yamazaki
- Department of Environmental Science & Engineering, Graduate School of Science & Engineering, Yamaguchi University, Yamaguchi, 753-8512, Japan
| |
Collapse
|
10
|
He G, Zhang H, King JD, Blankenship RE. Structural analysis of the homodimeric reaction center complex from the photosynthetic green sulfur bacterium Chlorobaculum tepidum. Biochemistry 2014; 53:4924-30. [PMID: 25014729 PMCID: PMC4372062 DOI: 10.1021/bi5006464] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
![]()
The reaction center (RC) complex
of the green sulfur bacterium Chlorobaculum tepidum is composed of the Fenna–Matthews–Olson
antenna protein (FMO) and the reaction center core (RCC) complex.
The RCC complex has four subunits: PscA, PscB, PscC, and PscD. We
studied the FMO/RCC complex by chemically cross-linking the purified
sample followed by biochemical and spectroscopic analysis. Blue-native
gels showed that there were two types of FMO/RCC complexes, which
are consistent with complexes with one copy of FMO per RCC and two
copies of FMO per RCC. Sodium dodecyl sulfate–polyacrylamide
gel electrophoresis analysis of the samples after cross-linking showed
that all five subunits of the RC can be linked by three different
cross-linkers: bissulfosuccinimidyl suberate, disuccinimidyl suberate,
and 3,3-dithiobis-sulfosuccinimidyl propionate. The interaction sites
of the cross-linked complex were also studied using liquid chromatography
coupled to tandem mass spectrometry. The results indicated that FMO,
PscB, PscD, and part of PscA are exposed on the cytoplasmic side of
the membrane. PscD helps stabilize FMO to the reaction center and
may facilitate transfer of the electron from the RC to ferredoxin.
The soluble domain of the heme-containing cytochrome subunit PscC
and part of the core subunit PscA are located on the periplasmic side
of the membrane. There is a close relationship between the periplasmic
portions of PscA and PscC, which is needed for the efficient transfer
of the electron between PscC and P840.
Collapse
Affiliation(s)
- Guannan He
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | | | | | | |
Collapse
|
11
|
Pšenčík J, Butcher SJ, Tuma R. Chlorosomes: Structure, Function and Assembly. THE STRUCTURAL BASIS OF BIOLOGICAL ENERGY GENERATION 2014. [DOI: 10.1007/978-94-017-8742-0_5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
|
12
|
Kovács SÁ, Bricker WP, Niedzwiedzki DM, Colletti PF, Lo CS. Computational determination of the pigment binding motif in the chlorosome protein a of green sulfur bacteria. PHOTOSYNTHESIS RESEARCH 2013; 118:231-247. [PMID: 24078352 DOI: 10.1007/s11120-013-9920-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Accepted: 08/31/2013] [Indexed: 06/02/2023]
Abstract
We present a molecular-scale model of Bacteriochlorophyll a (BChl a) binding to the chlorosome protein A (CsmA) of Chlorobaculum tepidum, and the aggregated pigment–protein dimer, as determined from protein–ligand docking and quantum chemistry calculations. Our calculations provide strong evidence that the BChl a molecule is coordinated to the His25 residue of CsmA, with the magnesium center of the bacteriochlorin ring situated\3 A° from the imidazole nitrogen atom of the histidine sidechain, and the phytyl tail aligned along the nonpolar residues of the a-helix of CsmA. We also confirm that the Qy band in the absorption spectra of BChl a experiences a large (?16 to ?43 nm) redshift when aggregated with another BChl a molecule in the CsmA dimer, compared to the BChl a in solvent; this redshift has been previously established by experimental researchers. We propose that our model of the BChl a–CsmA binding motif, where the dimer contains parallel aligned N-terminal regions, serves as the smallest repeating unit in a larger model of the para-crystalline chlorosome baseplate protein.
Collapse
|
13
|
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.
Collapse
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
| | | |
Collapse
|
14
|
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
| |
Collapse
|
15
|
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.
Collapse
Affiliation(s)
- T Wade Johnson
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | | | | | | | | |
Collapse
|
16
|
Comparative and Functional Genomics of Anoxygenic Green Bacteria from the Taxa Chlorobi, Chloroflexi, and Acidobacteria. FUNCTIONAL GENOMICS AND EVOLUTION OF PHOTOSYNTHETIC SYSTEMS 2012. [DOI: 10.1007/978-94-007-1533-2_3] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
17
|
Huang RYC, Wen J, Blankenship RE, Gross ML. Hydrogen-deuterium exchange mass spectrometry reveals the interaction of Fenna-Matthews-Olson protein and chlorosome CsmA protein. Biochemistry 2011; 51:187-93. [PMID: 22142245 DOI: 10.1021/bi201620y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In green-sulfur bacterial photosynthesis, excitation energy absorbed by a peripheral antenna structure known as the chlorosome is sequentially transferred through a baseplate protein to the Fenna-Matthews-Olson (FMO) antenna protein and into the reaction center, which is embedded in the cytoplasmic membrane. The molecular details of the optimized photosystem architecture required for efficient energy transfer are only partially understood. We address here the question of how the baseplate interacts with the FMO protein by applying hydrogen/deuterium exchange coupled with enzymatic digestion and mass spectrometry analysis to reveal the binding interface of the FMO antenna protein and the CsmA baseplate protein. Several regions on the FMO protein, represented by peptides consisting of 123-129, 140-149, 150-162, 191-208, and 224-232, show significant decreases of deuterium uptake after CsmA binding. The results indicate that the CsmA protein interacts with the Bchl a #1 side of the FMO protein. A global picture including peptide-level details for the architecture of the photosystem from green-sulfur bacteria can now be drawn.
Collapse
Affiliation(s)
- Richard Y-C Huang
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | | | | | | |
Collapse
|
18
|
Garcia Costas AM, Tsukatani Y, Romberger SP, Oostergetel GT, Boekema EJ, Golbeck JH, Bryant DA. Ultrastructural analysis and identification of envelope proteins of "Candidatus Chloracidobacterium thermophilum" chlorosomes. J Bacteriol 2011; 193:6701-11. [PMID: 21965575 PMCID: PMC3232888 DOI: 10.1128/jb.06124-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 09/23/2011] [Indexed: 11/20/2022] Open
Abstract
Chlorosomes are sac-like, light-harvesting organelles that characteristically contain very large numbers of bacteriochlorophyll (BChl) c, d, or e molecules. These antenna structures occur in chlorophototrophs belonging to some members of the Chlorobi and Chloroflexi phyla and are also found in a recently discovered member of the phylum Acidobacteria, "Candidatus Chloracidobacterium thermophilum." "Ca. Chloracidobacterium thermophilum" is the first aerobic organism discovered to possess chlorosomes as light-harvesting antennae for phototrophic growth. Chlorosomes were isolated from "Ca. Chloracidobacterium thermophilum" and subjected to electron microscopic, spectroscopic, and biochemical analyses. The chlorosomes of "Ca. Chloracidobacterium thermophilum" had an average size of ∼100 by 30 nm. Cryo-electron microscopy showed that the BChl c molecules formed folded or twisted, sheet-like structures with a lamellar spacing of ∼2.3 nm. Unlike the BChls in the chlorosomes of the green sulfur bacterium Chlorobaculum tepidum, concentric cylindrical nanotubes were not observed. Chlorosomes of "Ca. Chloracidobacterium thermophilum" contained a homolog of CsmA, the BChl a-binding, baseplate protein; CsmV, a protein distantly related to CsmI, CsmJ, and CsmX of C. tepidum, which probably binds a single [2Fe-2S] cluster; and five unique polypeptides (CsmR, CsmS, CsmT, CsmU, and a type II NADH dehydrogenase homolog). Although "Ca. Chloracidobacterium thermophilum" is an aerobe, energy transfer among the BChls in these chlorosomes was very strongly quenched in the presence of oxygen (as measured by quenching of fluorescence emission). The combined analyses showed that the chlorosomes of "Ca. Chloracidobacterium thermophilum" possess a number of unique features but also share some properties with the chlorosomes found in anaerobic members of other phyla.
Collapse
Affiliation(s)
| | | | | | - Gert T. Oostergetel
- Groningen Biomolecular Sciences and Biotechnology Institute, 9747 AG Groningen, The Netherlands
| | - Egbert J. Boekema
- Groningen Biomolecular Sciences and Biotechnology Institute, 9747 AG Groningen, The Netherlands
| | - John H. Golbeck
- Department of Biochemistry and Molecular Biology
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717
| |
Collapse
|
19
|
CsmA Protein is Associated with BChl a in the Baseplate Subantenna of Chlorosomes of the Photosynthetic Green Filamentous Bacterium Oscillochloris trichoides belonging to the Family Oscillochloridaceae. JOURNAL OF BIOPHYSICS 2011; 2011:860382. [PMID: 21941538 PMCID: PMC3175400 DOI: 10.1155/2011/860382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/30/2011] [Accepted: 07/05/2011] [Indexed: 12/05/2022]
Abstract
The baseplate subantenna in chlorosomes of green anoxygenic photosynthetic bacteria, belonging to the families Chloroflexaceae and Chlorobiaceae, is known to represent a complex of bacteriochlorophyll (BChl) a with the ~6 kDa CsmA proteins. Earlier, we showed the existence of a similar BChl a subantenna in chlorosomes of the photosynthetic green bacterium Oscillochloris trichoides, member of Oscillochloridaceae, the third family of green photosynthetic bacteria. However, this BChl a subantenna was not visually identified in absorption spectra of isolated Osc. trichoides chlorosomes in contrast to those of Chloroflexaceae and Chlorobiaceae. In this work, using room and low-temperature absorbance and fluorescence spectroscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of alkaline-treated and untreated chlorosomes of Osc. trichoides, we showed that the baseplate BChl a subantenna does exist in Oscillochloridaceae chlorosomes as a complex of BChl a with the 5.7 kDa CsmA protein. The present results support the idea that the baseplate subantenna, representing a complex of BChl a with a ~6 kDa CsmA protein, is a universal interface between the BChl c subantenna of chlorosomes and the nearest light-harvesting BChl a subantenna in all three known families of green anoxygenic photosynthetic bacteria.
Collapse
|
20
|
Kouyianou K, De Bock PJ, Müller SA, Nikolaki A, Rizos A, Krzyžánek V, Aktoudianaki A, Vandekerckhove J, Engel A, Gevaert K, Tsiotis G. The chlorosome of Chlorobaculum tepidum: Size, mass and protein composition revealed by electron microscopy, dynamic light scattering and mass spectrometry-driven proteomics. Proteomics 2011; 11:2867-80. [DOI: 10.1002/pmic.201000494] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 04/29/2011] [Accepted: 05/03/2011] [Indexed: 11/12/2022]
|
21
|
Mizoguchi T, Yoshitomi T, Harada J, Tamiaki H. Temperature- and Time-Dependent Changes in the Structure and Composition of Glycolipids during the Growth of the Green Sulfur Photosynthetic Bacterium Chlorobaculum tepidum. Biochemistry 2011; 50:4504-12. [DOI: 10.1021/bi2002339] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tadashi Mizoguchi
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Taichi Yoshitomi
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Jiro Harada
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume, Fukuoka 830-0011, Japan
| | - Hitoshi Tamiaki
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| |
Collapse
|
22
|
Schmidt Am Busch M, Müh F, El-Amine Madjet M, Renger T. The Eighth Bacteriochlorophyll Completes the Excitation Energy Funnel in the FMO Protein. J Phys Chem Lett 2011; 2:93-98. [PMID: 26295526 DOI: 10.1021/jz101541b] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The Fenna-Matthews-Olson (FMO) light-harvesting protein connects the outer antenna system (chlorosome/baseplate) with the reaction center complex in green sulfur bacteria. Since its first structure determination in the mid-70s, this pigment-protein complex has become an important model system to study excitation energy transfer. Recently, an additional bacteriochlorophyll a (the eighth) pigment was discovered in each subunit of this homotrimer. Our structure-based calculations of the optical properties of the FMO protein demonstrate that the eighth pigment is the linker to the baseplate, confirming recent suggestions from crystallographic studies.
Collapse
Affiliation(s)
- Marcel Schmidt Am Busch
- †Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Strasse 69, 4040 Linz, Austria
| | - Frank Müh
- ‡Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
| | - Mohamed El-Amine Madjet
- ‡Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
| | - Thomas Renger
- †Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Strasse 69, 4040 Linz, Austria
| |
Collapse
|
23
|
Oostergetel GT, van Amerongen H, Boekema EJ. The chlorosome: a prototype for efficient light harvesting in photosynthesis. PHOTOSYNTHESIS RESEARCH 2010; 104:245-55. [PMID: 20130996 PMCID: PMC2882566 DOI: 10.1007/s11120-010-9533-0] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 01/16/2010] [Indexed: 05/18/2023]
Abstract
Three phyla of bacteria include phototrophs that contain unique antenna systems, chlorosomes, as the principal light-harvesting apparatus. Chlorosomes are the largest known supramolecular antenna systems and contain hundreds of thousands of BChl c/d/e molecules enclosed by a single membrane leaflet and a baseplate. The BChl pigments are organized via self-assembly and do not require proteins to provide a scaffold for efficient light harvesting. Their excitation energy flows via a small protein, CsmA embedded in the baseplate to the photosynthetic reaction centres. Chlorosomes allow for photosynthesis at very low light intensities by ultra-rapid transfer of excitations to reaction centres and enable organisms with chlorosomes to live at extraordinarily low light intensities under which no other phototrophic organisms can grow. This article reviews several aspects of chlorosomes: the supramolecular and molecular organizations and the light-harvesting and spectroscopic properties. In addition, it provides some novel information about the organization of the baseplate.
Collapse
Affiliation(s)
- Gert T. Oostergetel
- Biophysical Chemistry, Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, The Netherlands
| | - Egbert J. Boekema
- Biophysical Chemistry, Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| |
Collapse
|
24
|
Pedersen MØ, Linnanto J, Frigaard NU, Nielsen NC, Miller M. A model of the protein-pigment baseplate complex in chlorosomes of photosynthetic green bacteria. PHOTOSYNTHESIS RESEARCH 2010; 104:233-243. [PMID: 20077007 DOI: 10.1007/s11120-009-9519-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2009] [Accepted: 12/16/2009] [Indexed: 05/28/2023]
Abstract
In contrast to photosynthetic reaction centers, which share the same structural architecture, more variety is found in the light-harvesting antenna systems of phototrophic organisms. The largest antenna system described, so far, is the chlorosome found in anoxygenic green bacteria, as well as in a recently discovered aerobic phototroph. Chlorosomes are the only antenna system, in which the major light-harvesting pigments are organized in self-assembled supramolecular aggregates rather than on protein scaffolds. This unique feature is believed to explain why some green bacteria are able to carry out photosynthesis at very low light intensities. Encasing the chlorosome pigments is a protein-lipid monolayer including an additional antenna complex: the baseplate, a two-dimensional paracrystalline structure containing the chlorosome protein CsmA and bacteriochlorophyll a (BChl a). In this article, we review current knowledge of the baseplate antenna complex, which physically and functionally connects the chlorosome pigments to the reaction centers via the Fenna-Matthews-Olson protein, with special emphasis on the well-studied green sulfur bacterium Chlorobaculum tepidum (previously Chlorobium tepidum). A possible role for the baseplate in the biogenesis of chlorosomes is discussed. In the final part, we present a structural model of the baseplate through combination of a recent NMR structure of CsmA and simulation of circular dichroism and optical spectra for the CsmA-BChl a complex.
Collapse
Affiliation(s)
- Marie Ø Pedersen
- Center for Insoluble Protein Structures, Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, Arhus C, Aarhus, Denmark
| | | | | | | | | |
Collapse
|
25
|
Envelope proteins of the CsmB/CsmF and CsmC/CsmD motif families influence the size, shape, and composition of chlorosomes in Chlorobaculum tepidum. J Bacteriol 2009; 191:7109-20. [PMID: 19749040 DOI: 10.1128/jb.00707-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chlorosome envelope of Chlorobaculum tepidum contains 10 proteins that belong to four structural motif families. A previous mutational study (N.-U. Frigaard, H. Li, K. J. Milks, and D. A. Bryant, J. Bacteriol. 186:646-653, 2004) suggested that some of these proteins might have redundant functions. Six multilocus mutants were constructed to test the effects of eliminating the proteins of the CsmC/CsmD and CsmB/CsmF motif families, and the resulting strains were characterized physiologically and biochemically. Mutants lacking all proteins of either motif family still assembled functional chlorosomes, and as measured by growth rates of the mutant strains, light harvesting was affected only at the lowest light intensities tested (9 and 32 micromol photons m(-2) s(-1)). The size, composition, and biogenesis of the mutant chlorosomes differed from those of wild-type chlorosomes. Mutants lacking proteins of the CsmC/CsmD motif family produced smaller chlorosomes than did the wild type, and the Q(y) absorbance maximum for the bacteriochlorophyll c aggregates in these chlorosomes was strongly blueshifted. Conversely, the chlorosomes of mutants lacking proteins of the CsmB/CsmF motif family were larger than wild-type chlorosomes, and the Q(y) absorption for their bacteriochlorophyll c aggregates was redshifted. When CsmH was eliminated in addition to other proteins of either motif family, chlorosomes had smaller diameters. These data show that the chlorosome envelope proteins of the CsmB/CsmF and CsmC/CsmD families play important roles in determining chlorosome size as well as the assembly and supramolecular organization of the bacteriochlorophyll c aggregates within the chlorosome.
Collapse
|
26
|
Structure of chlorosomes from the green filamentous bacterium Chloroflexus aurantiacus. J Bacteriol 2009; 191:6701-8. [PMID: 19717605 DOI: 10.1128/jb.00690-09] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The green filamentous bacterium Chloroflexus aurantiacus employs chlorosomes as photosynthetic antennae. Chlorosomes contain bacteriochlorophyll aggregates and are attached to the inner side of a plasma membrane via a protein baseplate. The structure of chlorosomes from C. aurantiacus was investigated by using a combination of cryo-electron microscopy and X-ray diffraction and compared with that of Chlorobi species. Cryo-electron tomography revealed thin chlorosomes for which a distinct crystalline baseplate lattice was visualized in high-resolution projections. The baseplate is present only on one side of the chlorosome, and the lattice dimensions suggest that a dimer of the CsmA protein is the building block. The bacteriochlorophyll aggregates inside the chlorosome are arranged in lamellae, but the spacing is much greater than that in Chlorobi species. A comparison of chlorosomes from different species suggested that the lamellar spacing is proportional to the chain length of the esterifying alcohols. C. aurantiacus chlorosomes accumulate larger quantities of carotenoids under high-light conditions, presumably to provide photoprotection. The wider lamellae allow accommodation of the additional carotenoids and lead to increased disorder within the lamellae.
Collapse
|
27
|
Wen J, Zhang H, Gross ML, Blankenship RE. Membrane orientation of the FMO antenna protein from Chlorobaculum tepidum as determined by mass spectrometry-based footprinting. Proc Natl Acad Sci U S A 2009; 106:6134-9. [PMID: 19339500 PMCID: PMC2669346 DOI: 10.1073/pnas.0901691106] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Indexed: 11/18/2022] Open
Abstract
The high excitation energy-transfer efficiency demanded in photosynthetic organisms relies on the optimal pigment-protein binding orientation in the individual protein complexes and also on the overall architecture of the photosystem. In green sulfur bacteria, the membrane-attached Fenna-Matthews-Olson (FMO) antenna protein functions as a "wire" to connect the large peripheral chlorosome antenna complex with the reaction center (RC), which is embedded in the cytoplasmic membrane (CM). Energy collected by the chlorosome is funneled through the FMO to the RC. Although there has been considerable effort to understand the relationships between structure and function of the individual isolated complexes, the specific architecture for in vivo interactions of the FMO protein, the CM, and the chlorosome, ensuring highly efficient energy transfer, is still not established experimentally. Here, we describe a mass spectrometry-based method that probes solvent-exposed surfaces of the FMO by labeling solvent-exposed aspartic and glutamic acid residues. The locations and extents of labeling of FMO on the native membrane in comparison with it alone and on a chlorosome-depleted membrane reveal the orientation. The large differences in the modification of certain peptides show that the Bchl a #3 side of the FMO trimer interacts with the CM, which is consistent with recent theoretical predictions. Moreover, the results also provide direct experimental evidence to confirm the overall architecture of the photosystem from Chlorobaculum tepidum (C. tepidum) and give information on the packing of the FMO protein in its native environment.
Collapse
Affiliation(s)
| | - Hao Zhang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
| | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
| | | |
Collapse
|
28
|
Abstract
The green phototrophic bacteria contain a unique complement of chlorophyll pigments, which self-assemble efficiently into antenna structures known as chlorosomes with little involvement of protein. The few proteins found in chlorosomes have previously been thought to have a primarily structural function. The biosynthetic pathway of the chlorosome pigments, bacteriochlorophylls c, d, and e, is not well understood. In this report, we used spectroscopic, proteomic, and gene expression approaches to investigate the chlorosome proteins of the green filamentous anoxygenic phototrophic bacterium Chloroflexus aurantiacus. Surprisingly, Mg-protoporphyrin IX monomethyl ester (oxidative) cyclase, AcsF, was identified under anaerobic growth conditions. The AcsF protein was found in the isolated chlorosome fractions, and the proteomics analysis suggested that significant portions of the AcsF proteins are not accessible to protease digestion. Additionally, quantitative real-time PCR studies showed that the transcript level of the acsF gene is not lower in anaerobic growth than in semiaerobic growth. Since the proposed enzymatic activity of AcsF requires molecular oxygen, our studies suggest that the roles of AcsF in C. aurantiacus need to be investigated further.
Collapse
|
29
|
Pedersen MØ, Underhaug J, Dittmer J, Miller M, Nielsen NC. The three-dimensional structure of CsmA: A small antenna protein from the green sulfur bacteriumChlorobium tepidum. FEBS Lett 2008; 582:2869-74. [DOI: 10.1016/j.febslet.2008.07.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 06/25/2008] [Accepted: 07/12/2008] [Indexed: 10/21/2022]
|
30
|
Tamiaki H, Yoshimura H, Shimamura Y, Kunieda M. Self-aggregation behavior of synthetic zinc 3-hydroxymethyl-13/15-carbonyl-chlorins as models of main light-harvesting components in photosynthetic green bacteria. PHOTOSYNTHESIS RESEARCH 2008; 95:223-8. [PMID: 17912608 DOI: 10.1007/s11120-007-9247-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Accepted: 09/07/2007] [Indexed: 05/17/2023]
Abstract
Zinc complexes of 3-hydroxymethyl-13/15-carbonyl-chlorins having a six-membered lactone as the E-ring were prepared by modifying purpurin-18 as models of bacteriochlorophyll-d, one of the chlorophyllous pigments in the main light-harvesting antenna systems (chlorosomes) of green photosynthetic bacteria. The synthetic 13-carbonylated compound self-aggregated in 1%(v/v) tetrahydrofuran and hexane to give large oligomers possessing red-shifted and broadened electronic absorption bands and intense circular dichroism bands at the shifted Q ( y ) region, indicating that the supramolecular structure of the resulting self-aggregate was similar to those of natural and artificial chlorosomal aggregates. The red-shift value observed here was smaller than the reported values in chlorosomal pigments having a five-membered keto-ring, which was ascribable to a weaker intermolecular hydrogen-bonding of 13-C=O with 3(1)-OH in a supramolecule of the former self-aggregate and suppression of the pi-pi interaction among the composite chlorins. On the other hand, the isomeric 15-carbonylated molecule was monomeric even in the nonpolar organic solvent, confirming the reported proposal that the linear orientation of three interactive moieties, OH, C=O and Zn, in a molecule is requisite for its chlorosomal self-aggregation.
Collapse
Affiliation(s)
- Hitoshi Tamiaki
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
| | | | | | | |
Collapse
|
31
|
Oostergetel GT, Reus M, Gomez Maqueo Chew A, Bryant DA, Boekema EJ, Holzwarth AR. Long-range organization of bacteriochlorophyll in chlorosomes of Chlorobium tepidum investigated by cryo-electron microscopy. FEBS Lett 2007; 581:5435-9. [PMID: 17981156 DOI: 10.1016/j.febslet.2007.10.045] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Accepted: 10/25/2007] [Indexed: 10/22/2022]
Abstract
Intact chlorosomes of Chlorobium tepidum were embedded in amorphous ice layers and examined by cryo-electron microscopy to study the long-range organization of bacteriochlorophyll (BChl) layers. End-on views reveal that chlorosomes are composed of several multi-layer tubules of variable diameter (20-30 nm) with some locally undulating non-tubular lamellae in between. The multi-layered tubular structures are more regular and larger in a C. tepidum mutant that only synthesizes [8-ethyl, 12-methyl]-BChl d. Our data show that wild-type C. tepidum chlorosomes do not have a highly regular, long-range BChl c layer organization and that they contain several multi-layered tubules rather than single-layer tubules or exclusively undulating lamellae as previously proposed.
Collapse
Affiliation(s)
- Gert T Oostergetel
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | | | | | | | | | | |
Collapse
|
32
|
Alpha-helices direct excitation energy flow in the Fenna Matthews Olson protein. Proc Natl Acad Sci U S A 2007; 104:16862-7. [PMID: 17940020 DOI: 10.1073/pnas.0708222104] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In photosynthesis, light is captured by antenna proteins. These proteins transfer the excitation energy with almost 100% quantum efficiency to the reaction centers, where charge separation takes place. The time scale and pathways of this transfer are controlled by the protein scaffold, which holds the pigments at optimal geometry and tunes their excitation energies (site energies). The detailed understanding of the tuning of site energies by the protein has been an unsolved problem since the first high-resolution crystal structure of a light-harvesting antenna appeared >30 years ago [Fenna RE, Matthews BW (1975) Nature 258:573-577]. Here, we present a combined quantum chemical/electrostatic approach to compute site energies that considers the whole protein in atomic detail and provides the missing link between crystallography and spectroscopy. The calculation of site energies of the Fenna-Matthews-Olson protein results in optical spectra that are in quantitative agreement with experiment and reveals an unexpectedly strong influence of the backbone of two alpha-helices. The electric field from the latter defines the direction of excitation energy flow in the Fenna-Matthews-Olson protein, whereas the effects of amino acid side chains, hitherto thought to be crucial, largely compensate each other. This result challenges the current view of how energy flow is regulated in pigment-protein complexes and demonstrates that attention has to be paid to the backbone architecture.
Collapse
|
33
|
Ikonen TP, Li H, Pšenčík J, Laurinmäki PA, Butcher SJ, Frigaard NU, Serimaa RE, Bryant DA, Tuma R. X-ray scattering and electron cryomicroscopy study on the effect of carotenoid biosynthesis to the structure of Chlorobium tepidum chlorosomes. Biophys J 2007; 93:620-8. [PMID: 17468163 PMCID: PMC1896238 DOI: 10.1529/biophysj.106.101444] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chlorosomes, the main antenna complexes of green photosynthetic bacteria, were isolated from null mutants of Chlorobium tepidum, each of which lacked one enzyme involved in the biosynthesis of carotenoids. The effects of the altered carotenoid composition on the structure of the chlorosomes were studied by means of x-ray scattering and electron cryomicroscopy. The chlorosomes from each mutant strain exhibited a lamellar arrangement of the bacteriochlorophyll c aggregates, which are the major constituents of the chlorosome interior. However, the carotenoid content and composition had a pronounced effect on chlorosome biogenesis and structure. The results indicate that carotenoids with a sufficiently long conjugated system are important for the biogenesis of the chlorosome baseplate. Defects in the baseplate structure affected the shape of the chlorosomes and were correlated with differences in the arrangement of lamellae and spacing between the lamellar planes of bacteriochlorophyll aggregates. In addition, comparisons among the various mutants enabled refinement of the assignments of the x-ray scattering peaks. While the main scattering peaks come from the lamellar structure of bacteriochlorophyll c aggregates, some minor peaks may originate from the paracrystalline arrangement of CsmA in the baseplate.
Collapse
Affiliation(s)
- T. P. Ikonen
- Department of Physical Sciences, University of Helsinki, Helsinki, Finland; Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, Pennsylvania; Department of Chemical Physics and Optics, Charles University, Prague, Czech Republic; Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; and Department of Molecular Biology, University of Copenhagen, Denmark
| | - H. Li
- Department of Physical Sciences, University of Helsinki, Helsinki, Finland; Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, Pennsylvania; Department of Chemical Physics and Optics, Charles University, Prague, Czech Republic; Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; and Department of Molecular Biology, University of Copenhagen, Denmark
| | - J. Pšenčík
- Department of Physical Sciences, University of Helsinki, Helsinki, Finland; Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, Pennsylvania; Department of Chemical Physics and Optics, Charles University, Prague, Czech Republic; Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; and Department of Molecular Biology, University of Copenhagen, Denmark
| | - P. A. Laurinmäki
- Department of Physical Sciences, University of Helsinki, Helsinki, Finland; Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, Pennsylvania; Department of Chemical Physics and Optics, Charles University, Prague, Czech Republic; Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; and Department of Molecular Biology, University of Copenhagen, Denmark
| | - S. J. Butcher
- Department of Physical Sciences, University of Helsinki, Helsinki, Finland; Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, Pennsylvania; Department of Chemical Physics and Optics, Charles University, Prague, Czech Republic; Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; and Department of Molecular Biology, University of Copenhagen, Denmark
| | - N.-U. Frigaard
- Department of Physical Sciences, University of Helsinki, Helsinki, Finland; Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, Pennsylvania; Department of Chemical Physics and Optics, Charles University, Prague, Czech Republic; Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; and Department of Molecular Biology, University of Copenhagen, Denmark
| | - R. E. Serimaa
- Department of Physical Sciences, University of Helsinki, Helsinki, Finland; Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, Pennsylvania; Department of Chemical Physics and Optics, Charles University, Prague, Czech Republic; Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; and Department of Molecular Biology, University of Copenhagen, Denmark
| | - D. A. Bryant
- Department of Physical Sciences, University of Helsinki, Helsinki, Finland; Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, Pennsylvania; Department of Chemical Physics and Optics, Charles University, Prague, Czech Republic; Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; and Department of Molecular Biology, University of Copenhagen, Denmark
| | - R. Tuma
- Department of Physical Sciences, University of Helsinki, Helsinki, Finland; Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, Pennsylvania; Department of Chemical Physics and Optics, Charles University, Prague, Czech Republic; Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; and Department of Molecular Biology, University of Copenhagen, Denmark
| |
Collapse
|
34
|
Kim H, Li H, Maresca JA, Bryant DA, Savikhin S. Triplet exciton formation as a novel photoprotection mechanism in chlorosomes of Chlorobium tepidum. Biophys J 2007; 93:192-201. [PMID: 17434948 PMCID: PMC1914439 DOI: 10.1529/biophysj.106.103556] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chlorosomes comprise thousands of bacteriochlorophylls (BChl c, d, or e) in a closely packed structure surrounded by a lipid-protein envelope and additionally contain considerable amounts of carotenoids, quinones, and BChl a. It has been suggested that carotenoids in chlorosomes provide photoprotection by rapidly quenching triplet excited states of BChl via a triplet-triplet energy transfer mechanism that prevents energy transfer to oxygen and the formation of harmful singlet oxygen. In this work we studied triplet energy transfer kinetics and photodegradation of chlorosomes isolated from wild-type Chlorobium tepidum and from genetically modified species with different types of carotenoids and from a carotenoid-free mutant. Supporting a photoprotective function of carotenoids, carotenoid-free chlorosomes photodegrade approximately 3 times faster than wild-type chlorosomes. However, a significant fraction of the BChls forms a long-lived, triplet-like state that does not interact with carotenoids or with oxygen. We propose that these states are triplet excitons that form due to triplet-triplet interaction between the closely packed BChls. Numerical exciton simulations predict that the energy of these triplet excitons may fall below that of singlet oxygen and triplet carotenoids; this would prevent energy transfer from triplet BChl. Thus, the formation of triplet excitons in chlorosomes serves as an alternative photoprotection mechanism.
Collapse
Affiliation(s)
- Hanyoup Kim
- Department of Physics, Purdue University, West Lafayette, Indiana, USA
| | | | | | | | | |
Collapse
|
35
|
Hohmann-Marriott MF, Blankenship RE. Hypothesis on chlorosome biogenesis in green photosynthetic bacteria. FEBS Lett 2007; 581:800-3. [PMID: 17303128 DOI: 10.1016/j.febslet.2007.01.078] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 01/31/2007] [Accepted: 01/31/2007] [Indexed: 11/25/2022]
Abstract
Chlorosomes are specialized compartments that constitute the main light harvesting system of green sulfur bacteria (GSB) and some filamentous anoxygenic phototrophs (FAP). Chlorosome biogenesis promises to be a complex process requiring the generation of a unilayer membrane and the targeting of bacteriochlorophyll, carotenoids, quinones, and proteins to the chlorosome. The biogenesis of chlorosomes as well as their presence in two distinct bacterial groups, GSB and FAP, remains enigmatic. The photosynthetic machinery and overall metabolic characteristics of these two bacterial groups are very different, and horizontal gene transfer has been proposed to explain chlorosome distribution. Chlorosomes have been considered to be unique structures that require a specific assembly machinery. We propose that no special machinery is required for chlorosome assembly. Instead, it is suggested that chlorosomes are a special form of lipid body. We present a model for chlorosome biogenesis that combines aspects of lipid body biogenesis with established chlorosome characteristics and may help explain the presence of chlorosomes in two metabolically diverse organism groups.
Collapse
|