1
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Tournaire MD, Scharff LB, Kramer M, Goss T, Vuorijoki L, Rodriguez‐Heredia M, Wilson S, Kruse I, Ruban A, Balk L. J, Hase T, Jensen P, Hanke GT. Ferredoxin C2 is required for chlorophyll biosynthesis and accumulation of photosynthetic antennae in Arabidopsis. Plant Cell Environ 2023; 46:3287-3304. [PMID: 37427830 PMCID: PMC10947542 DOI: 10.1111/pce.14667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 06/09/2023] [Accepted: 06/22/2023] [Indexed: 07/11/2023]
Abstract
Ferredoxins (Fd) are small iron-sulphur proteins, with sub-types that have evolved for specific redox functions. Ferredoxin C2 (FdC2) proteins are essential Fd homologues conserved in all photosynthetic organisms and a number of different FdC2 functions have been proposed in angiosperms. Here we use RNAi silencing in Arabidopsis thaliana to generate a viable fdC2 mutant line with near-depleted FdC2 protein levels. Mutant leaves have ~50% less chlorophyll a and b, and chloroplasts have poorly developed thylakoid membrane structure. Transcriptomics indicates upregulation of genes involved in stress responses. Although fdC2 antisense plants show increased damage at photosystem II (PSII) when exposed to high light, PSII recovers at the same rate as wild type in the dark. This contradicts literature proposing that FdC2 regulates translation of the D1 subunit of PSII, by binding to psbA transcript. Measurement of chlorophyll biosynthesis intermediates revealed a build-up of Mg-protoporphyrin IX, the substrate of the aerobic cyclase. We localise FdC2 to the inner chloroplast envelope and show that the FdC2 RNAi line has a disproportionately lower protein abundance of antennae proteins, which are nuclear-encoded and must be refolded at the envelope after import.
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Affiliation(s)
| | - Lars B. Scharff
- Department of Plant and Environmental Sciences, Copenhagen Plant Science CentreUniversity of CopenhagenFrederiksbergDenmark
| | - Manuela Kramer
- School of Biological and Behavioural sciencesQueen Mary University of LondonLondonUK
| | - Tatjana Goss
- Department of Plant PhysiologyOsnabrück UniversityOsnabrückGermany
| | | | | | - Sam Wilson
- School of Biological and Behavioural sciencesQueen Mary University of LondonLondonUK
| | - Inga Kruse
- Department of Plant PhysiologyOsnabrück UniversityOsnabrückGermany
| | - Alexander Ruban
- School of Biological and Behavioural sciencesQueen Mary University of LondonLondonUK
| | | | - Toshiharu Hase
- Institute for Protein ResearchOsaka UniversityOsakaJapan
| | - Poul‐Erik Jensen
- Department of Food ScienceUniversity of CopenhagenFrederiksbergDenmark
| | - Guy T. Hanke
- School of Biological and Behavioural sciencesQueen Mary University of LondonLondonUK
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2
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Gagliardi F, Snider S, Roncelli F, Pompeo E, De Domenico P, Klungtvedt V, Barzaghi LR, Comai S, Zuber V, Bulotta A, Bandiera A, Castellano A, Ruban A, Mortini P. P14.03.B Glutamate excitotoxicity in brain metastases from lung, breast, and melanoma treated with stereotactic radiosurgery. Neuro Oncol 2022. [DOI: 10.1093/neuonc/noac174.288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Brain metastases (BM) are the most frequent neoplasm in the central nervous system (CNS) and primary tumors frequently involved are melanoma, lung cancer and breast cancer. CNS localisation is associated with poor prognosis, and stereotactic radiosurgery (SRS) represents a treatment option for patients with a good performance status. Glutamate (Glu) is a neurotransmitter which plays a facilitating role in carcinogenesis and progression of malignant tumors, as well as in excitotoxicity. Glu efflux from the brain is regulated by scavengers glutamic oxaloacetic transaminase (GOT), glutamate-pyruvate transaminase (GPT) and lactate dehydrogenase (LDH), with aspartate and lactate as catabolites. Glu efflux from the brain seems to be impaired in advanced-stage cancers, resulting in increased blood Glu levels where scavengers exert a protective role. Our hypothesis is that serum Glu and scavengers’ levels are related to neuroinvasion and treatment response in patients with BM and may represent potential biomarkers for BM course and prognosis.
Material and Methods
Serum Glu scavengers (GOT1, GPT and LDH), serum Glu, aspartate and lactate levels are collected in included patients treated and grouped in A) BM group of patients affected by BM from lung or breast cancer or melanoma, treated with SRS; B) Control-1 group of patients affected by lung cancer, breast cancer or melanoma but without BM and C) Control-2 group of patients with benign intracranial lesions (meningiomas, acoustic schwannomas) treated with SRS.In A) and C) serum metabolites and scavengers will be analyzed before and after SRS treatment (at 3, 6, 9 months) while in B) analyzed once. Blood levels in A) and C) help in identifying differences related to malignancy, the role of SRS and the association with disease control, while blood levels in A) and B) help in detecting differences related to BMs. Exclusion criteria are surgical or previous radiosurgical treatment for BM. This study has received Institutional Ethical Committee approval on 3rd August 2020 (Project NCH04-2020, Clinicaltrials.gov identifier: NCT04785521).
Preliminary results
Comparison between BM group (n = 32) and Control-1 (n=18) revealed a significant difference in LDH (271.93 vs 217.56 U/L; p 0.041) and lactate (1.86 vs 1.34 mmol/L, p = 0.022) and a trend towards significance in glutamate (103.43 vs 73.74 µmol/L, p = 0.07). Comparison between BM group (n=32) and Control-2 (n = 37) revealed a difference in LDH (271.93 vs 210.89 U/L; p < 0.001), lactate (1.86 vs 1.24 mmol/L; p < 0.001), aspartate (16.36 vs 10.22 µmol/L, p 0.006) and glutamate levels (123 vs 103 µmol/L, p = 0.052).
Conclusion
The present study is the first one addressing serum glutamate and scavenger levels in patients with BM. If the hypothesis will be confirmed, new targets in glutamate signalling pathway could be identified to define new therapeutic strategies in this challenging disease.
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Affiliation(s)
- F Gagliardi
- Department of Neurosurgery and Gamma Knife Radiosurgery, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | - S Snider
- Department of Neurosurgery and Gamma Knife Radiosurgery, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | - F Roncelli
- Department of Neurosurgery and Gamma Knife Radiosurgery, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | - E Pompeo
- Department of Neurosurgery and Gamma Knife Radiosurgery, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | - P De Domenico
- Department of Neurosurgery and Gamma Knife Radiosurgery, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | | | - L R Barzaghi
- Department of Neurosurgery and Gamma Knife Radiosurgery, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | - S Comai
- Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | - V Zuber
- Breast Surgery Unit, San Raffaele Scientific Institute, Vita-Salute Universitye , Milan , Italy
| | - A Bulotta
- Department of Oncology, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | - A Bandiera
- Department of Thoracic Surgery, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | - A Castellano
- Neuroradiology Unit and CERMAC, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
| | - A Ruban
- Nursing Deparment, Steyer School of Health Professions, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel-Aviv University (TAU) , Tel Aviv , Israel
| | - P Mortini
- Department of Neurosurgery and Gamma Knife Radiosurgery, San Raffaele Scientific Institute, Vita-Salute University , Milan , Italy
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3
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Affiliation(s)
- Alexander Ruban
- SBBS, Queen Mary University of London - Mile End Campus, United Kingdom
| | - Francesco Saccon
- School of Biological and Chemical Sciences, Queen Mary University of London - Mile End Campus, United Kingdom
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4
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Artes Vivancos JM, van Stokkum IHM, Saccon F, Hontani Y, Kloz M, Ruban A, van Grondelle R, Kennis JTM. Unraveling the Excited-State Dynamics and Light-Harvesting Functions of Xanthophylls in Light-Harvesting Complex II Using Femtosecond Stimulated Raman Spectroscopy. J Am Chem Soc 2020; 142:17346-17355. [PMID: 32878439 PMCID: PMC7564077 DOI: 10.1021/jacs.0c04619] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
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Photosynthesis
in plants starts with the capture of photons by
light-harvesting complexes (LHCs). Structural biology and spectroscopy
approaches have led to a map of the architecture and energy transfer
pathways between LHC pigments. Still, controversies remain regarding
the role of specific carotenoids in light-harvesting and photoprotection,
obligating the need for high-resolution techniques capable of identifying
excited-state signatures and molecular identities of the various pigments
in photosynthetic systems. Here we demonstrate the successful application
of femtosecond stimulated Raman spectroscopy (FSRS) to a multichromophoric
biological complex, trimers of LHCII. We demonstrate the application
of global and target analysis (GTA) to FSRS data and utilize it to
quantify excitation migration in LHCII trimers. This powerful combination
of techniques allows us to obtain valuable insights into structural,
electronic, and dynamic information from the carotenoids of LHCII
trimers. We report spectral and dynamical information on ground- and
excited-state vibrational modes of the different pigments, resolving
the vibrational relaxation of the carotenoids and the pathways of
energy transfer to chlorophylls. The lifetimes and spectral characteristics
obtained for the S1 state confirm that lutein 2 has a distorted conformation
in LHCII and that the lutein 2 S1 state does not transfer to chlorophylls,
while lutein 1 is the only carotenoid whose S1 state plays a significant
energy-harvesting role. No appreciable energy transfer takes place
from lutein 1 to lutein 2, contradicting recent proposals regarding
the functions of the various carotenoids (Son et al. Chem.2019, 5 (3), 575–584). Also, our results demonstrate that FSRS can be used in combination
with GTA to simultaneously study the electronic and vibrational landscapes
in LHCs and pave the way for in-depth studies of photoprotective conformations
in photosynthetic systems.
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Affiliation(s)
- Juan M Artes Vivancos
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.,Department of Chemistry, Kennedy College of Science, University of Massachusetts-Lowell, One University Avenue, Lowell, Massachusetts 01854, United States
| | - Ivo H M van Stokkum
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Francesco Saccon
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road/E1 4NS London, U.K
| | - Yusaku Hontani
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Miroslav Kloz
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Alexander Ruban
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road/E1 4NS London, U.K
| | - Rienk van Grondelle
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - John T M Kennis
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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5
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Abstract
Gastroparesis is characterized by delayed gastric emptying, with symptoms such as nausea, vomiting and abdominal pain, in the absence of mechanical obstruction. In most cases, it is idiopathic although diabetes mellitus is another leading cause. The physiology of gastric emptying is a complex process which is influenced by various inputs including the central nervous system, enteric nervous system and gut hormones. Developments in our understanding of gastroparesis have now demonstrated dysfunction in these systems, thus disrupting normal gastric emptying. Once mechanical obstruction is excluded, gastric scintigraphy remains the gold standard for diagnosis although wireless motility capsule and breath testing are alternative methods for diagnosis. Treatment for gastroparesis is challenging, and widely available therapies are often limited either by their poor evidence for efficacy or concerns over their long-term safety profile. Novel prokinetic agents have shown initial promise in clinical trials, and new endoscopic techniques such as gastric per-oral endoscopic myotomy are emerging. These new treatment modalities may provide an option in refractory gastroparesis with the adage of reduced morbidity compared to surgical treatments.
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Affiliation(s)
- A Sullivan
- Homerton University Hospital, London, UK
| | | | - A Ruban
- Department of Surgery and Cancer, Imperial College, London, UK.
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6
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Maximov D, Talyshev A, Ruban A, Kozyrev A. Upgrade of the KEDR detector DAQ system. EPJ Web Conf 2020. [DOI: 10.1051/epjconf/202024501004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The KEDR experiment is ongoing at the VEPP-4M e+e− collider at Budker INP in Novosibirsk. The collider center of mass energy range covers a wide spectrum from 2 to 11 GeV. Most of the up-to-date statistics were taken at the lower end of the energy range around the charmonia region. Planned activities at greater energies up to the bottomonia would lead to a significant increase of event recording rates and accelerator backgrounds, thus stressing the existing DAQ and trigger systems beyond their limits. The described DAQ upgrade plan includes: the redesign of the trigger electronics using modern components to improve the trigger decision time; the development of new readout processors using ethernet connections; new software for collecting events and electronics management; high level of parallelization of data transfers and events processing; improved reliability based on readout computing cluster with redundancy. The upgraded DAQ system is going to be very flexible and could be considered as a concept prototype of the projected BINP Super Charm-Tau Factory.
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7
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Tsivion H, Perets N, Ben-Zur T, Bikovsky L, Goldshmit Y, Ruban A, Offen D. Mscs-derived evs as potential treatment in a phencyclidine model of schizophrenia. Cytotherapy 2019. [DOI: 10.1016/j.jcyt.2019.04.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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Affiliation(s)
- Julia Bailey-Serres
- Center for Plant Cell Biology and Department of Botany and Plant Sciences, University of California, Riverside, California 92521; Plant Ecophysiology, Department of Biology, Utrecht University, 3584 CH, Utrecht, The Netherlands
| | - Ronald Pierik
- Plant Ecophysiology, Department of Biology, Utrecht University, 3584 CH, Utrecht, The Netherlands
| | - Alexander Ruban
- Department of Cell and Molecular Biology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Astrid Wingler
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland
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9
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Ruban A. Surgical treatment of traumatic macular hole. Acta Ophthalmol 2017. [DOI: 10.1111/j.1755-3768.2017.03513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Pérez-Mato M, Ramos-Cabrer P, Sobrino T, Blanco M, Ruban A, Mirelman D, Menendez P, Castillo J, Campos F. Human recombinant glutamate oxaloacetate transaminase 1 (GOT1) supplemented with oxaloacetate induces a protective effect after cerebral ischemia. Cell Death Dis 2014; 5:e992. [PMID: 24407245 PMCID: PMC4040715 DOI: 10.1038/cddis.2013.507] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 11/13/2013] [Accepted: 11/18/2013] [Indexed: 11/09/2022]
Abstract
Blood glutamate scavenging is a novel and attractive protecting strategy to reduce the excitotoxic effect of extracellular glutamate released during ischemic brain injury. Glutamate oxaloacetate transaminase 1 (GOT1) activation by means of oxaloacetate administration has been used to reduce the glutamate concentration in the blood. However, the protective effect of the administration of the recombinant GOT1 (rGOT1) enzyme has not been yet addressed in cerebral ischemia. The aim of this study was to analyze the protective effect of an effective dose of oxaloacetate and the human rGOT1 alone and in combination with a non-effective dose of oxaloacetate in an animal model of ischemic stroke. Sixty rats were subjected to a transient middle cerebral artery occlusion (MCAO). Infarct volumes were assessed by magnetic resonance imaging (MRI) before treatment administration, and 24 h and 7 days after MCAO. Brain glutamate levels were determined by in vivo MR spectroscopy (MRS) during artery occlusion (80 min) and reperfusion (180 min). GOT activity and serum glutamate concentration were analyzed during the occlusion and reperfusion period. Somatosensory test was performed at baseline and 7 days after MCAO. The three treatments tested induced a reduction in serum and brain glutamate levels, resulting in a reduction in infarct volume and sensorimotor deficit. Protective effect of rGOT1 supplemented with oxaloacetate at 7 days persists even when treatment was delayed until at least 2 h after onset of ischemia. In conclusion, our findings indicate that the combination of human rGOT1 with low doses of oxaloacetate seems to be a successful approach for stroke treatment
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Affiliation(s)
- M Pérez-Mato
- Department of Neurology, Neurovascular Area, Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain
| | - P Ramos-Cabrer
- Department of Neurology, Neurovascular Area, Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain
| | - T Sobrino
- Department of Neurology, Neurovascular Area, Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain
| | - M Blanco
- Department of Neurology, Neurovascular Area, Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain
| | - A Ruban
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
| | - D Mirelman
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - P Menendez
- 1] Josep Carreras Leukemia Research Institute, Cell Therapy Program of the University of Barcelona, Barcelona, Spain [2] Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - J Castillo
- Department of Neurology, Neurovascular Area, Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain
| | - F Campos
- Department of Neurology, Neurovascular Area, Clinical Neurosciences Research Laboratory, Hospital Clínico Universitario, Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, Santiago de Compostela, Spain
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11
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Ruban A, Berkutzki T, Cooper I, Mohar B, Teichberg V. 914 Blood Glutamate Scavengers Prolong the Survival of Rats and Mice With Brain-implanted Gliomas. Eur J Cancer 2012. [DOI: 10.1016/s0959-8049(12)71543-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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12
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Rozhenko AB, Ruban A, Thelen V, Nieger M, Airola K, Schoeller WW, Niecke E. Island Homoaromaticity in the W‐Shaped 2,4‐Diphospha‐3‐arsapentadienide Anion and Related Compounds – Theoretical and Experimental Investigations. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201101360] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Alexander B. Rozhenko
- Institute of Organic Chemistry of the National Academy of Sciences of Ukraine, Murmans'ka str. 5, 02660 Kyiv, Ukraine, Fax: +380‐44‐573‐2543
- Fakultät für Chemie der Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
| | - Alexander Ruban
- Institute of Organic Chemistry of the National Academy of Sciences of Ukraine, Murmans'ka str. 5, 02660 Kyiv, Ukraine, Fax: +380‐44‐573‐2543
- Anorganisch‐Chemisches Institut der Universität Bonn, Gerhard‐Domagk‐Str. 1, 5300 Bonn, Germany
| | - Vera Thelen
- Anorganisch‐Chemisches Institut der Universität Bonn, Gerhard‐Domagk‐Str. 1, 5300 Bonn, Germany
| | - Martin Nieger
- Anorganisch‐Chemisches Institut der Universität Bonn, Gerhard‐Domagk‐Str. 1, 5300 Bonn, Germany
- Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P. O. Box 55 (A.I. Virtasen aukio 1), 00014 University of Helsinki, Finland
| | - Karri Airola
- Department of Chemistry, University of Jyväskylä, P. O. Box 35, 40114 Jyväskylä, Finland
| | - Wolfgang W. Schoeller
- Fakultät für Chemie der Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
- Department of Chemistry, University of California, Riverside, CA 92521‐0403, USA
| | - Edgar Niecke
- Anorganisch‐Chemisches Institut der Universität Bonn, Gerhard‐Domagk‐Str. 1, 5300 Bonn, Germany
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13
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Gall A, Berera R, Alexandre MTA, Pascal AA, Bordes L, Mendes-Pinto MM, Andrianambinintsoa S, Stoitchkova KV, Marin A, Valkunas L, Horton P, Kennis JTM, van Grondelle R, Ruban A, Robert B. Molecular adaptation of photoprotection: triplet states in light-harvesting proteins. Biophys J 2011; 101:934-42. [PMID: 21843485 DOI: 10.1016/j.bpj.2011.05.057] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 05/12/2011] [Accepted: 05/13/2011] [Indexed: 10/17/2022] Open
Abstract
The photosynthetic light-harvesting systems of purple bacteria and plants both utilize specific carotenoids as quenchers of the harmful (bacterio)chlorophyll triplet states via triplet-triplet energy transfer. Here, we explore how the binding of carotenoids to the different types of light-harvesting proteins found in plants and purple bacteria provides adaptation in this vital photoprotective function. We show that the creation of the carotenoid triplet states in the light-harvesting complexes may occur without detectable conformational changes, in contrast to that found for carotenoids in solution. However, in plant light-harvesting complexes, the triplet wavefunction is shared between the carotenoids and their adjacent chlorophylls. This is not observed for the antenna proteins of purple bacteria, where the triplet is virtually fully located on the carotenoid molecule. These results explain the faster triplet-triplet transfer times in plant light-harvesting complexes. We show that this molecular mechanism, which spreads the location of the triplet wavefunction through the pigments of plant light-harvesting complexes, results in the absence of any detectable chlorophyll triplet in these complexes upon excitation, and we propose that it emerged as a photoprotective adaptation during the evolution of oxygenic photosynthesis.
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Affiliation(s)
- Andrew Gall
- CEA, Institute of Biology and Technology of Saclay, Gif sur Yvette, France
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14
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Crouchman S, Ruban A, Horton P. PsbS enhances nonphotochemical fluorescence quenching in the absence of zeaxanthin. FEBS Lett 2006; 580:2053-8. [PMID: 16545380 DOI: 10.1016/j.febslet.2006.03.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Revised: 02/28/2006] [Accepted: 03/02/2006] [Indexed: 11/23/2022]
Abstract
Leaves and chloroplasts from Arabidopsis plants with increased amounts of PsbS protein showed the same percentage increase in nonphotochemical quenching in comparison to the wild type both in the presence and absence of zeaxanthin. The absorption change at 525-535 nm was also more pronounced in both cases. It is suggested that PsbS alone can cause the quenching, supporting the model in which zeaxanthin acts as an allosteric activator and is not the primary cause of the process. It is proposed that PsbS acts as a trigger of the conformational change that leads to the establishment of nonphotochemical quenching.
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Affiliation(s)
- Sophie Crouchman
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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15
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Horton P, Wentworth M, Ruban A. Control of the light harvesting function of chloroplast membranes: the LHCII-aggregation model for non-photochemical quenching. FEBS Lett 2005; 579:4201-6. [PMID: 16051219 DOI: 10.1016/j.febslet.2005.07.003] [Citation(s) in RCA: 263] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Accepted: 07/07/2005] [Indexed: 11/22/2022]
Abstract
Dissipation of excess excitation energy within the photosystem II light-harvesting antenna (LHCII) by non-photochemical quenching (NPQ) is an important photoprotective process in plants. An update to a hypothesis for the mechanism of NPQ [FEBS Letters 292, 1991] is presented. The impact of recent advances in understanding the structure, organisation and photophysics of LHCII is assessed. We show possible locations of the predicted regulatory and quenching pigment-binding sites in the structural model of the major LHCII. We suggest that NPQ is a highly regulated concerted response of the organised thylakoid macrostructure, which can include different mechanisms and sites at different times.
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Affiliation(s)
- Peter Horton
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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16
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Pascal AA, Liu Z, Broess K, van Oort B, van Amerongen H, Wang C, Horton P, Robert B, Chang W, Ruban A. Molecular basis of photoprotection and control of photosynthetic light-harvesting. Nature 2005; 436:134-7. [PMID: 16001075 DOI: 10.1038/nature03795] [Citation(s) in RCA: 444] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Accepted: 05/09/2005] [Indexed: 11/08/2022]
Abstract
In order to maximize their use of light energy in photosynthesis, plants have molecules that act as light-harvesting antennae, which collect light quanta and deliver them to the reaction centres, where energy conversion into a chemical form takes place. The functioning of the antenna responds to the extreme changes in the intensity of sunlight encountered in nature. In shade, light is efficiently harvested in photosynthesis. However, in full sunlight, much of the energy absorbed is not needed and there are vitally important switches to specific antenna states, which safely dissipate the excess energy as heat. This is essential for plant survival, because it provides protection against the potential photo-damage of the photosynthetic membrane. But whereas the features that establish high photosynthetic efficiency have been highlighted, almost nothing is known about the molecular nature of the dissipative states. Recently, the atomic structure of the major plant light-harvesting antenna protein, LHCII, has been determined by X-ray crystallography. Here we demonstrate that this is the structure of a dissipative state of LHCII. We present a spectroscopic analysis of this crystal form, and identify the specific changes in configuration of its pigment population that give LHCII the intrinsic capability to regulate energy flow. This provides a molecular basis for understanding the control of photosynthetic light-harvesting.
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Affiliation(s)
- Andrew A Pascal
- Service de Biophysique des Fonctions Membranaires, URA2096/CNRS and DBJC/CEA, CEA-Saclay, 91191 Gif-sur-Yvette Cedex, France
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Abstract
The photosystem II (PSII) light-harvesting system carries out two essential functions, the efficient collection of light energy for photosynthesis, and the regulated dissipation of excitation energy in excess of that which can be used. This dual function requires structural and functional flexibility, in which light-harvesting proteins respond to an external signal, the thylakoid DeltapH, to induce feedback control. This process, referred to as non-photochemical quenching (NPQ) depends upon the xanthophyll cycle and the PsbS protein. In nature, NPQ is heterogeneous in terms of kinetics and capacity, and this adapts photosynthetic systems to the specific dynamic features of the light environment. The molecular features of the thylakoid membrane which may enable this flexibility and plasticity are discussed.
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Affiliation(s)
- Peter Horton
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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Ruban A, Lavaud J, Rousseau B, Guglielmi G, Horton P, Etienne AL. The super-excess energy dissipation in diatom algae: comparative analysis with higher plants. Photosynth Res 2004; 82:165-75. [PMID: 16151872 DOI: 10.1007/s11120-004-1456-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
When grown at intermittent light regime, diatom alga Phaeodactylum tricornutum is able to form photoprotective non-photochemical chlorophyll fluorescence quenching (NPQ) three to five times larger than that observed in the higher plants. This quenching is sustained in the dark for 5 to 10 min, reverses completely within approximately 1 h and seems to be very tightly related to the presence of the zeaxanthin analogue, diatoxanthin. Addition of the uncoupler NH4Cl before illumination can completely abolish formation of NPQ, revealing the DeltapH-dependency of the xanthophyll cycle activity. Once established, NPQ can also be almost completely reversed by the uncoupler. However, the higher NPQ is formed the more time is required for its reversal. At the point when the fluorescence was approximately 90% recovered the level of illumination-induced diatoxanthin was found to be only partially reduced. This indicates that the proton gradient is a key triggering factor of NPQ. It was also noticed that NPQ in Phaeodactylum cells was absent even when majority of reaction centers were closed and the plastoquinone pool was significantly reduced. The absence of NPQ at these conditions could be due to very low levels of DeltapH. It is likely that in diatoms alternative sources of protons such as the PS I cyclic electron transfer and/or chlororespiration are important in generating the proton gradient sufficient to trigger NPQ. Absorption changes associated with the xanthophyll cycle activity were found to be larger than those for higher plants. The position of the positive maximum in the difference spectrum illuminated-minus-dark was 512-514 nm in comparison to the 505-508 nm for leaves. The 535 nm band associated with NPQ in plants is absent in Phaeodactylum. An uncoupler-sensitive absorption change at 522 nm was discovered. Kinetics of NPQ showed linear correlation with the 522 nm absorption change.
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Affiliation(s)
- Alexander Ruban
- The Robert Hill Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, UK
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Aspinall-O'Dea M, Wentworth M, Pascal A, Robert B, Ruban A, Horton P. In vitro reconstitution of the activated zeaxanthin state associated with energy dissipation in plants. Proc Natl Acad Sci U S A 2002; 99:16331-5. [PMID: 12461177 PMCID: PMC138611 DOI: 10.1073/pnas.252500999] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Indexed: 11/18/2022] Open
Abstract
Dissipation of excess light energy in plant photosynthetic membranes plays an important role in the response of plants to the environment, providing short-term balancing between the intensity of sunlight and photosynthetic capacity. The carotenoid zeaxanthin and the photosystem II subunit PsbS play vital roles in this process, but the mechanism of their action is largely unexplained. Here we report that the isolated photosystem II subunit PsbS was able to bind exogenous zeaxanthin, the binding resulting in a strong red shift in the absorption spectrum, and the appearance of characteristic features in the resonance Raman spectrum and a distinct circular dichroism spectrum, indicating pigment-protein, as well as specific pigment-pigment, interaction. A strong shift in the absorption spectrum of PsbS phenylalanine residues after zeaxanthin binding was observed. It is concluded that zeaxanthin binding to PsbS is the origin of the well known energy dissipation-related 535-nm absorption change that we showed in vivo to arise from activation of 1-2 molecules of this pigment. The altered properties of zeaxanthin and PsbS that result from this interaction provide the first direct indication about how they regulate energy dissipation.
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Affiliation(s)
- Mark Aspinall-O'Dea
- Robert Hill Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
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Affiliation(s)
- M Blättner
- Anorganisch-Chemisches Institut der Universität Gerhard-Domagk-Strasse 1, 53121 Bonn (Germany)
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Blättner M, Ruban A, Gudat D, Nieger M, Niecke E. From Neutral to Cationic Adducts: Investigations on the System Halogeno (Imino) Phosphane (Bisiminophosphorane)/DMAP. PHOSPHORUS SULFUR 1999. [DOI: 10.1080/10426509908053496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- M. Blättner
- a Institut für Anorganische Chemie , Gerhard-Domagk-Straße 1, D-53121 , Bonn , Germany
| | - A. Ruban
- a Institut für Anorganische Chemie , Gerhard-Domagk-Straße 1, D-53121 , Bonn , Germany
| | - D. Gudat
- a Institut für Anorganische Chemie , Gerhard-Domagk-Straße 1, D-53121 , Bonn , Germany
| | - M. Nieger
- a Institut für Anorganische Chemie , Gerhard-Domagk-Straße 1, D-53121 , Bonn , Germany
| | - E. Niecke
- a Institut für Anorganische Chemie , Gerhard-Domagk-Straße 1, D-53121 , Bonn , Germany
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Ruban A. Two Convenient Routes for the Preparation of Bis[bis(trimethylsilyl)methylene](halogeno)-phosphoranes. SYNTHESIS-STUTTGART 1997. [DOI: 10.1055/s-1997-1301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Schinkels B, Ruban A, Nieger M, Niecke E. Synthesis, crystal structure and rearrangement of a methylene(ylene)- phosphorane containing a CH2-moiety at an sp2-hybridized phosphorus(v) centre. Chem Commun (Camb) 1997. [DOI: 10.1039/a607402b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Worgul B, Likhtaryov I, Kundiev Y, Medvedovsky C, Sergienko N, Parkhomenko G, Chumak V, Ruban A, Vitte P, Wu B, Wegener A. 1148 Cataractogenesis in the chernobyl liquidators: The effects of dose and age. Vision Res 1995. [DOI: 10.1016/0042-6989(95)90044-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ruban A, Nieger M, Niecke E. Synthese und Struktur von Bis(tri-tert-butylphenyl)-iminohalogenphosphoranen XP(NtBu3C6H2)2. Angew Chem Int Ed Engl 1993. [DOI: 10.1002/ange.19931051042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ruban A, Nieger M, Niecke E. Synthesis and Structure of Bis(tri-tert-butylphenyl)iminohalogenphosphoranes X?P(?NtBu3C6H2)2. Angew Chem Int Ed Engl 1993. [DOI: 10.1002/anie.199314191] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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