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Reinot T, Khmelnitskiy A, Kell A, Jassas M, Jankowiak R. Exciton Lifetime Distributions and Population Dynamics in the FMO Protein Complex from Prosthecochloris aestuarii. ACS OMEGA 2021; 6:5990-6008. [PMID: 33681637 PMCID: PMC7931385 DOI: 10.1021/acsomega.1c00286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Significant protein rearrangement upon excitation and energy transfer in Fenna-Matthews-Olson protein of Prosthecochloris aestuarii results in a modified energy landscape, which induces more changes in pigment site energies than predicted by the "standard" hole-burning theory. The energy changes are elucidated by simulations while investigating the effects of site-dependent disorder, both static (site-energy distribution widths) and dynamic (spectral density shapes). The resulting optimized site energies and their fluctuations are consistent with relative differences observed in inhomogeneous widths calculated by recent molecular dynamic simulations. Two sets of different spectral densities reveal how their shapes affect the population dynamics and distribution of exciton lifetimes. Calculations revealed the wavelength-dependent distributions of exciton lifetimes (T 1) in the femtosecond to picosecond time frame. We suggest that the calculated multimodal and asymmetric wavelength-dependent T 1 distributions offer more insight into the interpretation of resonant hole-burned (HB) spectra, kinetic traces in two-dimensional (2D) electronic spectroscopy experiments, and widely used global analyses in fitting data from transient absorption experiments.
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Affiliation(s)
- Tonu Reinot
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Anton Khmelnitskiy
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Adam Kell
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Mahboobe Jassas
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Ryszard Jankowiak
- Department
of Chemistry, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
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2
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Kholod Y, DeFilippo M, Reed B, Valdez D, Gillan G, Kosenkov D. Excitation energy transfer pathways in light‐harvesting proteins: Modeling with PyFREC. J Comput Chem 2017; 39:438-449. [DOI: 10.1002/jcc.25134] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 11/13/2017] [Accepted: 11/27/2017] [Indexed: 01/06/2023]
Affiliation(s)
- Yana Kholod
- Department of Chemistry and Physics, 400 Cedar AveMonmouth UniversityWest Long Branch New Jersey07764
| | - Michael DeFilippo
- Department of Chemistry and Physics, 400 Cedar AveMonmouth UniversityWest Long Branch New Jersey07764
| | - Brittany Reed
- Department of Chemistry and Physics, 400 Cedar AveMonmouth UniversityWest Long Branch New Jersey07764
| | - Danielle Valdez
- Department of Chemistry and Physics, 400 Cedar AveMonmouth UniversityWest Long Branch New Jersey07764
| | - Grant Gillan
- Department of Chemistry and Physics, 400 Cedar AveMonmouth UniversityWest Long Branch New Jersey07764
| | - Dmytro Kosenkov
- Department of Chemistry and Physics, 400 Cedar AveMonmouth UniversityWest Long Branch New Jersey07764
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3
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Harada J, Shibata Y, Teramura M, Mizoguchi T, Kinoshita Y, Yamamoto K, Tamiaki H. In Vivo Energy Transfer from Bacteriochlorophyll c,d,e, orfto Bacteriochlorophyll ain Wild-Type and Mutant Cells of the Green Sulfur BacteriumChlorobaculum limnaeum. CHEMPHOTOCHEM 2017. [DOI: 10.1002/cptc.201700164] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Jiro Harada
- Department of Medical Biochemistry; Kurume University School of Medicine; Kurume 830-0011 Japan
| | - Yutaka Shibata
- Department of Chemistry, Graduate School of Science; Tohoku University; Sendai 980-8578 Japan
| | - Misato Teramura
- Graduate School of Life Sciences; Ritsumeikan University; Kusatsu 525-8577 Japan
| | - Tadashi Mizoguchi
- Graduate School of Life Sciences; Ritsumeikan University; Kusatsu 525-8577 Japan
| | - Yusuke Kinoshita
- Graduate School of Life Sciences; Ritsumeikan University; Kusatsu 525-8577 Japan
| | - Ken Yamamoto
- Department of Medical Biochemistry; Kurume University School of Medicine; Kurume 830-0011 Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences; Ritsumeikan University; Kusatsu 525-8577 Japan
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4
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Plasmonic bio-sensing for the Fenna-Matthews-Olson complex. Sci Rep 2017; 7:39720. [PMID: 28045089 PMCID: PMC5206648 DOI: 10.1038/srep39720] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/25/2016] [Indexed: 12/25/2022] Open
Abstract
We study theoretically the bio-sensing capabilities of metal nanowire surface plasmons. As a specific example, we couple the nanowire to specific sites (bacteriochlorophyll) of the Fenna-Matthews-Olson (FMO) photosynthetic pigment protein complex. In this hybrid system, we find that when certain sites of the FMO complex are subject to either the suppression of inter-site transitions or are entirely disconnected from the complex, the resulting variations in the excitation transfer rates through the complex can be monitored through the corresponding changes in the scattering spectra of the incident nanowire surface plasmons. We also find that these changes can be further enhanced by changing the ratio of plasmon-site couplings. The change of the Fano lineshape in the scattering spectra further reveals that “site 5” in the FMO complex plays a distinct role from other sites. Our results provide a feasible way, using single photons, to detect mutation-induced, or bleaching-induced, local defects or modifications of the FMO complex, and allows access to both the local and global properties of the excitation transfer in such systems.
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5
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Saga Y, Hirota K, Harada J, Tamiaki H. In Vitro Enzymatic Activities of Bacteriochlorophyll a Synthase Derived from the Green Sulfur Photosynthetic Bacterium Chlorobaculum tepidum. Biochemistry 2015; 54:4998-5005. [PMID: 26258685 DOI: 10.1021/acs.biochem.5b00311] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The activity of an enzyme encoded by the CT1610 gene in the green sulfur photosynthetic bacterium Chlorobaculum tepidum, which was annotated as bacteriochlorophyll (BChl) a synthase, BchG (denoted as tepBchG), was examined in vitro using the lysates of Escherichia coli containing the heterologously expressed enzyme. BChl a possessing a geranylgeranyl group at the 17-propionate residue (BChl aGG) was produced from bacteriochlorophyllide (BChlide) a and geranylgeranyl pyrophosphate in the presence of tepBchG. Surprisingly, tepBchG catalyzed the formation of BChl a bearing a farnesyl group (BChl aF) as in the enzymatic production of BChl aGG, indicating loose recognition of isoprenoid pyrophosphates in tepBchG. In contrast to such loose recognition of isoprenoid substrates, BChlide c and chlorophyllide a gave no esterifying product upon being incubated with geranylgeranyl or farnesyl pyrophosphate in the presence of tepBchG. These results confirm that tepBchG undoubtedly acts as the BChl a synthase in Cba. tepidum. The enzymatic activity of tepBchG was higher than that of BchG of Rhodobacter sphaeroides at 45 °C, although the former activity was lower than the latter below 35 °C.
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Affiliation(s)
- Yoshitaka Saga
- †Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan.,‡PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Keiya Hirota
- †Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Jiro Harada
- §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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6
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Kihara S, Hartzler DA, Orf GS, Blankenship RE, Savikhin S. The Fate of the Triplet Excitations in the Fenna–Matthews–Olson Complex. J Phys Chem B 2015; 119:5765-72. [DOI: 10.1021/jp512222c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Shigeharu Kihara
- Department
of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
| | - Daniel A. Hartzler
- Department
of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
| | - Gregory S. Orf
- Photosynthetic
Antenna Research Center, Departments of Chemistry and Biology, Washington University in St. Louis, St. Louis, Missouri 63110, United States
| | - Robert E. Blankenship
- Photosynthetic
Antenna Research Center, Departments of Chemistry and Biology, Washington University in St. Louis, St. Louis, Missouri 63110, United States
| | - Sergei Savikhin
- Department
of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
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7
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Kell A, Acharya K, Blankenship RE, Jankowiak R. On destabilization of the Fenna-Matthews-Olson complex of Chlorobaculum tepidum. PHOTOSYNTHESIS RESEARCH 2014; 120:323-329. [PMID: 24584903 DOI: 10.1007/s11120-014-9990-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 02/17/2014] [Indexed: 06/03/2023]
Abstract
The Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Chlorobaculum tepidum was studied with respect to its stability. We provide a critical assessment of published and recently measured optical spectra. FMO complexes were found to destabilize over time producing spectral shifts, with destabilized samples having significantly higher hole-burning efficiencies; indicating a remodeled protein energy landscape. Observed correlated peak shifts near 825 and 815 nm suggest possible correlated (protein) fluctuations. It is proposed that the value of 35 cm(-1) widely used for reorganization energy (E λ ), which has important implications for the contributions to the coherence rate (Kreisbeck and Kramer 3:2828-2833, 2012), in various modeling studies of two-dimensional electronic spectra is overestimated. We demonstrate that the value of E λ is most likely about 15-22 cm(-1) and suggest that spectra reported in the literature (often measured on different FMO samples) exhibit varied peak positions due to different purification/isolation procedures or destabilization effects.
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Affiliation(s)
- Adam Kell
- Department of Chemistry, Kansas State University, Manhattan, KS, 66506, USA
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8
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Pelzer KM, Can T, Gray SK, Morr DK, Engel GS. Coherent Transport and Energy Flow Patterns in Photosynthesis under Incoherent Excitation. J Phys Chem B 2014; 118:2693-702. [DOI: 10.1021/jp500746a] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Kenley M. Pelzer
- Department
of Chemistry, The James Franck Institute, and the Institute for Biophysical
Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Tankut Can
- The
James Franck Institute and the Department of Physics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Stephen K. Gray
- Center
for Nanoscale Materials, Argonne National Laboratory, 9700 South
Cass Avenue, Building 440, Argonne, Illinois 60439, United States
| | - Dirk K. Morr
- The
James Franck Institute and the Department of Physics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
- Department
of Physics, University of Illinois at Chicago, 845 West Taylor Street M/C 273, Chicago, Illinois 60607, United States
| | - Gregory S. Engel
- Department
of Chemistry, The James Franck Institute, and the Institute for Biophysical
Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
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9
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Herascu N, Kell A, Acharya K, Jankowiak R, Blankenship RE, Zazubovich V. Modeling of Various Optical Spectra in the Presence of Slow Excitation Energy Transfer in Dimers and Trimers with Weak Interpigment Coupling: FMO as an Example. J Phys Chem B 2014; 118:2032-40. [DOI: 10.1021/jp410586f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Nicoleta Herascu
- Department
of Physics, Concordia University, Montreal, H4B 1R6 Quebec, Canada
| | | | | | | | | | - Valter Zazubovich
- Department
of Physics, Concordia University, Montreal, H4B 1R6 Quebec, Canada
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10
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Orf GS, Niedzwiedzki DM, Blankenship RE. Intensity Dependence of the Excited State Lifetimes and Triplet Conversion Yield in the Fenna–Matthews–Olson Antenna Protein. J Phys Chem B 2014; 118:2058-69. [DOI: 10.1021/jp411020a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Gregory S. Orf
- Departments of Chemistry and Biology, §Photosynthetic Antenna
Research Center
(PARC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Dariusz M. Niedzwiedzki
- Departments of Chemistry and Biology, §Photosynthetic Antenna
Research Center
(PARC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Robert E. Blankenship
- Departments of Chemistry and Biology, §Photosynthetic Antenna
Research Center
(PARC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
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11
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Chen GY, Lambert N, Li CM, Chen YN, Nori F. Rerouting excitation transfers in the Fenna-Matthews-Olson complex. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:032120. [PMID: 24125226 DOI: 10.1103/physreve.88.032120] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Indexed: 06/02/2023]
Abstract
We investigate, using the hierarchy method, the entanglement and the excitation transfer efficiency of the Fenna-Matthews-Olson (FMO) complex under two different local modifications: the suppression of transitions between particular sites and localized changes to the protein environment. We find that inhibiting the connection between site 5 and site 6, or completely disconnecting site 5 from the complex, leads to a dramatic enhancement of the entanglement between site 6 and site 7. Similarly, the transfer efficiency actually increases if site 5 is entirely disconnected from the complex. We further show that if sites 5 and 7 are conjointly removed, the efficiency falls. This suggests that while not contributing to the transport efficiency in a normal complex, site 5 may introduce a redundant transport route in case of damage to site 7. Our results suggest an overall robustness of the excitation-energy transfer in the FMO complex under mutations, local defects, and other abnormal situations.
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Affiliation(s)
- Guang-Yin Chen
- Department of Physics and National Center for Theoretical Sciences, National Cheng-Kung University, Tainan 701, Taiwan and CEMS, RIKEN, Saitama, 351-0198, Japan
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12
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Tang JKH, Xu Y, Muhlmann GM, Zare F, Khin Y, Tam SW. Temperature shift effect on the Chlorobaculum tepidum chlorosomes. PHOTOSYNTHESIS RESEARCH 2013; 115:23-41. [PMID: 23435510 DOI: 10.1007/s11120-013-9800-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 01/29/2013] [Indexed: 06/01/2023]
Abstract
Chlorobaculum [Cba.] tepidum is known to grow optimally at 48-52 °C and can also be cultured at ambient temperatures. In this paper, we prepared constant temperature, temperature shift, and temperature shift followed by backshift cultures and investigated the intrinsic properties and spectral features of chlorosomes from those cultures using various approaches, including temperature-dependent measurements on circular dichroism (CD), UV-visible, and dynamic light scattering. Our studies indicate that (1) chlorosomes from constant temperature cultures at 50 and 30 °C exhibited more resistance to heat relative to temperature shift cultures; (2) as temperature increases bacteriochlorophyll c (BChl c) in chlorosomes is prone to demetalation, which forms bacteriopheophytin c, and degradation under aerobic conditions. Some BChl c aggregates inside reduced chlorosomes prepared in low-oxygen environments can reform after heat treatments; (3) temperature shift cultures synthesize and incorporate more BChl c homologs with a smaller substituent at C-8 on the chlorin ring and less BChl c homologs with a larger long-chain alcohol at C-17(3) versus constant-temperature cultures. We hypothesize that the long-chain alcohol at C-17(3) (and perhaps together with the substituent at C-8) may account for thermal stability of chlorosomes and the substituent at C-8 may assist self-assembling BChls; and (4) while almost identical absorption spectra are detected, chlorosomes from different growth conditions exhibited differences in the rotational length of the CD signal, and aerobic and reduced chlorosomes also display different Qy CD intensities. Further, chlorosomes exhibited changes of CD features in response to temperature increases. Additionally, we compare temperature-dependent studies for the Cba. tepidum chlorosomes and previous studies for the Chloroflexus aurantiacus chlorosomes. Together, our work provides useful and novel insights on the properties and organization of chlorosomes.
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13
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Eddie BJ, Hanson TE. Chlorobaculum tepidum TLS displays a complex transcriptional response to sulfide addition. J Bacteriol 2013; 195:399-408. [PMID: 23161024 PMCID: PMC3553837 DOI: 10.1128/jb.01342-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 11/08/2012] [Indexed: 11/20/2022] Open
Abstract
Chlorobaculum tepidum is a green sulfur bacterium (GSB) that is a model system for phototrophic sulfur oxidation. Despite over 2 decades of research, conspicuous gaps exist in our understanding of its electron donor metabolism and regulation. RNA sequencing (RNA-seq) was used to provide a global picture of the C. tepidum transcriptome during growth on thiosulfate as the sole electron donor and at time points following the addition of sulfide to such a culture. Following sulfide addition, 121 to 150 protein-coding genes displayed significant changes in expression depending upon the time point. These changes included a rapid decrease in expression of thiosulfate and elemental sulfur oxidation genes. Genes and gene loci with increased expression included CT1087, encoding a sulfide:quinone oxidoreductase required for growth in high sulfide concentrations; a polysulfide reductase-like complex operon, psrABC (CT0496 to CT0494); and, surprisingly, a large cluster of genes involved in iron acquisition. Finally, two genes that are conserved as a cassette in anaerobic bacteria and archaea, CT1276 and CT1277, displayed a strong increase in expression. The CT1277 gene product contains a DNA-binding domain, suggesting a role for it in sulfide-dependent gene expression changes.
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Affiliation(s)
- Brian J Eddie
- College of Earth, Ocean, and Environment and Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA
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14
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Xin Y, Pan J, Collins AM, Lin S, Blankenship RE. Excitation energy transfer and trapping dynamics in the core complex of the filamentous photosynthetic bacterium Roseiflexus castenholzii. PHOTOSYNTHESIS RESEARCH 2012; 111:149-156. [PMID: 21792612 DOI: 10.1007/s11120-011-9669-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 07/02/2011] [Indexed: 05/31/2023]
Abstract
The light-harvesting core complex of the thermophilic filamentous anoxygenic phototrophic bacterium Roseiflexus castenholzii is intrinsic to the cytoplasmic membrane and intimately bound to the reaction center (RC). Using ultrafast transient absorption and time-resolved fluorescence spectroscopy with selective excitation, energy transfer, and trapping dynamics in the core complex have been investigated at room temperature in both open and closed RCs. Results presented in this report revealed that the excited energy transfer from the BChl 800 to the BChl 880 band of the antenna takes about 2 ps independent of the trapping by the RC. The time constants for excitation quenching in the core antenna BChl 880 by open and closed RCs were found to be 60 and 210 ps, respectively. Assuming that the light harvesting complex is generally similar to LH1 of purple bacteria, the possible structural and functional aspects of this unique antenna complex are discussed. The results show that the core complex of Roseiflexus castenholzii contains characteristics of both purple bacteria and Chloroflexus aurantiacus.
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Affiliation(s)
- Yueyong Xin
- Departments of Biology and Chemistry, Washington University, St. Louis, MO 63130, USA.
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15
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Collins AM, Wen J, Blankenship RE. Photosynthetic Light-Harvesting Complexes. MOLECULAR SOLAR FUELS 2011. [DOI: 10.1039/9781849733038-00085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The light-harvesting antenna systems found in photosynthetic organisms function to collect light and transfer energy in the photon to a reaction center, where electron transfer gives rise to long-term energy storage. The antenna systems found in different types of photosynthetic organisms adapt the organisms to very different photic environments, and almost certainly have been invented multiple times during evolution. The diverse collection of photosynthetic antenna systems is described in terms of their pigment and protein components and their organization in the photosystem. The Förster theory is described as the physical basis of energy transfer in photosynthetic antennas, although in many systems it is not adequate to describe energy transfer in complexes with closely interacting pigments. Regulatory aspects of antennas are described, including the process of non-photochemical quenching.
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Affiliation(s)
- Aaron M. Collins
- Departments of Biology and Chemistry Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Jianzhong Wen
- Departments of Biology and Chemistry Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Robert E. Blankenship
- Departments of Biology and Chemistry Washington University in St. Louis, St. Louis, MO 63130 USA
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16
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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.
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Affiliation(s)
- Richard Y-C Huang
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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17
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Wen J, Zhang H, Gross ML, Blankenship RE. Native electrospray mass spectrometry reveals the nature and stoichiometry of pigments in the FMO photosynthetic antenna protein. Biochemistry 2011; 50:3502-11. [PMID: 21449539 DOI: 10.1021/bi200239k] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The nature and stoichiometry of pigments in the Fenna-Matthews-Olson (FMO) photosynthetic antenna protein complex were determined by native electrospray mass spectrometry. The FMO antenna complex was the first chlorophyll-containing protein that was crystallized. Previous results indicate that the FMO protein forms a trimer with seven bacteriochlorophyll a in each monomer. This model has long been a working basis to understand the molecular mechanism of energy transfer through pigment/pigment and pigment/protein coupling. Recent results have suggested, however, that an eighth bacteriochlorophyll is present in some subunits. In this report, a direct mass spectrometry measurement of the molecular weight of the intact FMO protein complex clearly indicates the existence of an eighth pigment, which is assigned as a bacteriochlorophyll a by mass analysis of the complex and HPLC analysis of the pigment. The eighth pigment is found to be easily lost during purification, which results in its partial occupancy in the mass spectra of the intact complex prepared by different procedures. The results are consistent with the recent X-ray structural models. The existence of the eighth bacteriochlorophyll a in this model antenna protein gives new insights into the functional role of the FMO protein and motivates the need for new theoretical and spectroscopic assignments of spectral features of the FMO protein.
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Affiliation(s)
- Jianzhong Wen
- Department of Biology, Washington University in St. Louis, Missouri 63130, United States
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18
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Hayes D, Wen J, Panitchayangkoon G, Blankenship RE, Engel GS. Robustness of electronic coherence in the Fenna–Matthews–Olson complex to vibronic and structural modifications. Faraday Discuss 2011; 150:459-69; discussion 505-32. [DOI: 10.1039/c0fd00030b] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Wen J, Tsukatani Y, Cui W, Zhang H, Gross ML, Bryant DA, Blankenship RE. Structural model and spectroscopic characteristics of the FMO antenna protein from the aerobic chlorophototroph, Candidatus Chloracidobacterium thermophilum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:157-64. [PMID: 20875391 DOI: 10.1016/j.bbabio.2010.09.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 09/15/2010] [Accepted: 09/17/2010] [Indexed: 11/17/2022]
Abstract
The Fenna-Matthews-Olson protein (FMO) binds seven or eight bacteriochlorophyll a (BChl a) molecules and is an important model antenna system for understanding pigment-protein interactions and mechanistic aspects of photosynthetic light harvesting. FMO proteins of green sulfur bacteria (Chlorobiales) have been extensively studied using a wide range of spectroscopic and theoretical approaches because of their stability, the spectral resolution of their pigments, their water-soluble nature, and the availability of high-resolution structural data. We obtained new structural and spectroscopic insights by studying the FMO protein from the recently discovered, aerobic phototrophic acidobacterium, Candidatus Chloracidobacterium thermophilum. Native C. thermophilum FMO is a trimer according to both analytical gel filtration and native-electrospray mass spectrometry. Furthermore, the mass of intact FMO trimer is consistent with the presence of 21-24 BChl a in each. Homology modeling of the C. thermophilum FMO was performed by using the structure of the FMO protein from Chlorobaculum tepidum as a template. C. thermophilum FMO differs from C. tepidum FMO in two distinct regions: the baseplate, CsmA-binding region and a region that is proposed to bind the reaction center subunit, PscA. C. thermophilum FMO has two fluorescence emission peaks at room temperature but only one at 77K. Temperature-dependent fluorescence spectroscopy showed that the two room-temperature emission peaks result from two excited-state BChl a populations that have identical fluorescence lifetimes. Modeling of the data suggests that the two populations contain 1-2 BChl and 5-6 BChl a molecules and that thermal equilibrium effects modulate the relative population of the two emitting states.
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Affiliation(s)
- Jianzhong Wen
- Department of Biology, Washington University in St. Louis, St. Louis MO 63130, USA
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