Photosynthesis Research - Current Research Articles
Current research articles: Photosynthesis
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Photosynthesis Research - published by Springer
... is an international journal open to papers of merit dealing with both basic and applied aspects of photosynthesis.
Fungicides are widely used to control pests in crop plants. However, it has been reported that these pesticides may have negative
effects on crop physiology, especially on photosynthesis. An alteration in photosynthesis might lead to a reduction in photoassimilate
production, resulting in a decrease in both growth and yield of crop plants. For example, a contact fungicide such as copper
inhibits photosynthesis by destroying chloroplasts, affecting photosystem II activity and chlorophyll biosynthesis. Systemic
fungicides such as benzimidazoles, anilides, and pyrimidine are also phytotoxic, whereas azoles stimulate photosynthesis.
This article focuses on the available information about toxic effects of fungicides on photosynthesis in crop plants, highlighting
the mechanisms of perturbation, interaction, and the target sites of different classes of fungicides.
Content Type Journal Article
Category Review
Pages 1-12
DOI 10.1007/s11120-012-9719-8
Authors
Anne-Noëlle Petit, Laboratoire de Stress, Défenses et Reproduction des Plantes, URVVC EA 2069, Université de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, Bâtiment 18, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France
Florence Fontaine, Laboratoire de Stress, Défenses et Reproduction des Plantes, URVVC EA 2069, Université de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, Bâtiment 18, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France
Parul Vatsa, Laboratoire de Stress, Défenses et Reproduction des Plantes, URVVC EA 2069, Université de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, Bâtiment 18, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France
Christophe Clément, Laboratoire de Stress, Défenses et Reproduction des Plantes, URVVC EA 2069, Université de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, Bâtiment 18, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France
Nathalie Vaillant-Gaveau, Laboratoire de Stress, Défenses et Reproduction des Plantes, URVVC EA 2069, Université de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, Bâtiment 18, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2, France
Photoassimilated carbons are converted to sucrose in green plant leaves and distributed to non-phototropic tissues to provide
carbon and energy. In photosynthetic sucrose biosynthesis, the chloroplast envelope triose phosphate/phosphate translocator
(TPT) and cytosolic fructose-1,6-bisphosphatase (cFBPase) are key components in photosynthetic sucrose biosynthesis. The simultaneous
overexpression of TPT and cFBPase was utilized to increase the source capacity of Arabidopsis. The TPT and cFBPase overexpression lines exhibited enhanced growth with larger rosette sizes and increased fresh weights compared with wild-type
(WT) plants. The simultaneous overexpression of TPT and cFBPase resulted in enhanced photosynthetic CO2 assimilation rates in moderate and elevated light conditions. During the phototropic period, the soluble sugar (sucrose,
glucose, and fructose) levels in the leaves of these transgenic lines were also higher than those of the WT plants. These
results suggest that the simultaneous overexpression of TPT and cFBPase enhances source capacity and consequently leads to growth enhancement in transgenic plants.
Content Type Journal Article
Category Regular Paper
Pages 1-8
DOI 10.1007/s11120-012-9720-2
Authors
Man-Ho Cho, Plant Metabolism Research Center and Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701 Korea
Areum Jang, Plant Metabolism Research Center and Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701 Korea
Seong Hee Bhoo, Plant Metabolism Research Center and Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701 Korea
Jong-Seong Jeon, Plant Metabolism Research Center and Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701 Korea
Tae-Ryong Hahn, Plant Metabolism Research Center and Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701 Korea
Phototrophs of the family Heliobacteriaceae contain the simplest known Type I reaction center (RC), consisting of a homodimeric
(PshA)2 core devoid of bound cytochromes and antenna proteins. Unlike plant and cyanobacterial Photosystem I in which the FA/FB protein, PsaC, is tightly bound to P700–FX cores, the RCs of Heliobacterium modesticaldum contain two FA/FB proteins, PshBI and PshBII, which are loosely bound to P800–FX cores. These two 2[4Fe–4S] ferredoxins have been proposed to function as mobile redox proteins, reducing downstream metabolic
partners much in the same manner as does [2Fe–2S] ferredoxin or flavodoxin (Fld) in PS I. Using P800–FX cores devoid of PshBI and PshBII, we show that iron–sulfur cluster FX directly reduces Fld without the involvement of FA or FB (Fld is used as a proxy for soluble redox proteins even though a gene encoding Fld is not identified in the H. modesticaldum genome). The reduction of Fld is suppressed by the addition of PshBI or PshBII, an effect explained by competition for the
electron on FX. In contrast, P700–FX cores require the presence of the PsaC, and hence, the FA/FB clusters for Fld (or ferredoxin) reduction. Thus, in H. modesticaldum, the interpolypeptide FX cluster serves as the terminal bound electron acceptor. This finding implies that the homodimeric (PshA)2 cores should be capable of donating electrons to a wide variety of yet-to-be characterized soluble redox partners.
Content Type Journal Article
Category Regular Paper
Pages 1-6
DOI 10.1007/s11120-012-9723-z
Authors
Steven P. Romberger, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
John H. Golbeck, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
The future environment may be altered by high concentrations of salt in the soil and elevated [CO2] in the atmosphere. These have opposite effects on photosynthesis. Generally, salt stress inhibits photosynthesis by stomatal
and non-stomatal mechanisms; in contrast, elevated [CO2] stimulates photosynthesis by increasing CO2 availability in the Rubisco carboxylating site and by reducing photorespiration. However, few studies have focused on the
interactive effects of these factors on photosynthesis. To elucidate this knowledge gap, we grew the barley plant, Hordeum vulgare (cv. Iranis), with and without salt stress at either ambient or elevated atmospheric [CO2] (350 or 700 ?mol mol?1 CO2, respectively). We measured growth, several photosynthetic and fluorescence parameters, and carbohydrate content. Under saline
conditions, the photosynthetic rate decreased, mostly because of stomatal limitations. Increasing salinity progressively increased
metabolic (photochemical and biochemical) limitation; this included an increase in non-photochemical quenching and a reduction
in the PSII quantum yield. When salinity was combined with elevated CO2, the rate of CO2 diffusion to the carboxylating site increased, despite lower stomatal and internal conductance. The greater CO2 availability increased the electron sink capacity, which alleviated the salt-induced metabolic limitations on the photosynthetic
rate. Consequently, elevated CO2 partially mitigated the saline effects on photosynthesis by maintaining favorable biochemistry and photochemistry in barley
leaves.
Content Type Journal Article
Category Regular Paper
Pages 1-15
DOI 10.1007/s11120-012-9721-1
Authors
Usue Pérez-López, Departamento de Biología Vegetal y Ecología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
Anabel Robredo, Departamento de Biología Vegetal y Ecología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
Maite Lacuesta, Departamento de Biología Vegetal y Ecología, Facultad de Farmacia, Universidad del País Vasco, UPV/EHU, Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Spain
Amaia Mena-Petite, Departamento de Biología Vegetal y Ecología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
Alberto Muñoz-Rueda, Departamento de Biología Vegetal y Ecología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
During the recent years, wide varieties of methodologies have been developed up to the level of commercial use to measure
photosynthetic electron transport by modulated chlorophyll a-in vivo fluorescence. It is now widely accepted that the ratio between electron transport rates and new biomass (PFl/BC) is not fixed and depends on many factors that are also taxonomically variable. In this study, the balance between photon
absorption and biomass production has been measured in two phycobilin-containing phototrophs, namely, a cyanobacterium and
a cryptophyte, which differ in their antenna organization. It is demonstrated that the different antenna organization exerts
influence on the regulation of the primary photosynthetic reaction and the dissipation of excessively absorbed radiation.
Although, growth rates and the quantum efficiency of biomass production of both phototrophs were comparable, the ratio PFl/BC was twice as high in the cryptophyte in comparison to the cyanobacterium. It is assumed that this discrepancy is because
of differences in the metabolic regulation of cell growth. In the cryptophyte, absorbed photosynthetic energy is used to convert
assimilated carbon directly into proteins and lipids, whereas in the cyanobacterium, the photosynthetic energy is preferentially
stored as carbohydrates.
Content Type Journal Article
Category Regular Paper
Pages 1-11
DOI 10.1007/s11120-011-9715-4
Authors
Christfried Kunath, Institute of Biology, Plant Physiology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
Torsten Jakob, Institute of Biology, Plant Physiology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
Christian Wilhelm, Institute of Biology, Plant Physiology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
Chromera velia is a newly discovered photosynthetic eukaryotic alga that has functional chloroplasts closely related to the apicoplast of
apicomplexan parasites. Recently, the chloroplast in C. velia was shown to be derived from the red algal lineage. Light-harvesting protein complexes (LHC), which are a group of proteins
involved in photon capture and energy transfer in photosynthesis, are important for photosynthesis efficiency, photo-adaptation/accumulation
and photo-protection. Although these proteins are encoded by genes located in the nucleus, LHC peptides migrate and function
in the chloroplast, hence the LHC may have a different evolutionary history compared to chloroplast evolution. Here, we compare
the phylogenetic relationship of the C. velia LHCs to LHCs from other photosynthetic organisms. Twenty-three LHC homologues retrieved from C. velia EST sequences were aligned according to their conserved regions. The C.velia LHCs are positioned in four separate groups on trees constructed by neighbour-joining, maximum likelihood and Bayesian methods.
A major group of seventeen LHCs from C. velia formed a separate cluster that was closest to dinoflagellate LHC, and to LHC and fucoxanthin chlorophyll-binding proteins
from diatoms. One C. velia LHC sequence grouped with LI1818/LI818-like proteins, which were recently identified as environmental stress-induced protein
complexes. Only three LHC homologues from C. velia grouped with the LHCs from red algae.
Content Type Journal Article
Category Regular Paper
Pages 1-10
DOI 10.1007/s11120-011-9710-9
Authors
Hao Pan, School of Biological Sciences (A08), Faculty of Sciences, University of Sydney, Sydney, NSW 2006, Australia
Jan Šlapeta, Faculty of Veterinary Science, University of Sydney, Sydney, NSW 2006, Australia
Dee Carter, Discipline of Microbiology, School of Molecular Biosciences, University of Sydney, Sydney, NSW 2006, Australia
Min Chen, School of Biological Sciences (A08), Faculty of Sciences, University of Sydney, Sydney, NSW 2006, Australia
Energy transfer (ET) processes between chromophores in R-phycoerythrin (R-PE) from Polysiphonia urceolata were studied by use of ultrafast spectroscopic methods. Several primary ET pathways were elaborated. A fluorescence decay
component with a time constant of several hundred picoseconds observed by streak camera is tentatively assigned to the reversible
formation of exciton traps between ?84 and ?84 pigment pairs. In order to investigate much faster ET processes in R-PE, a
noncollinear optical parametric amplifier based femtosecond time-resolved transient fluorescence spectrometer was employed.
The results reveal that the ET between ?84 and ?84 pigment pair has a time constant of 1–2 ps; the energy migration between
?84 and ?84 pairs within the R-PE trimer has a time constant of 30–40 ps. We also demonstrated an ET process from phycourobilin
to phycoerythrobilin with a time constant as fast as 2.5–3.0 ps, which was directly observed in fluorescence kinetics by selective
excitation of the phycourobilin molecules acting as the energy donor.
Content Type Journal Article
Category Regular Paper
Pages 1-6
DOI 10.1007/s11120-011-9708-3
Authors
Hailong Chen, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijng, 100190 China
Wei Dang, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijng, 100190 China
Jie Xie, Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190 China
Jingquan Zhao, Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190 China
Yuxiang Weng, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijng, 100190 China
Elastic incoherent neutron scattering (EINS), a non-invasive technique which is capable of measuring the mean square displacement
of atoms in the sample, has been widely used in biology for exploring the dynamics of proteins and lipid membranes but studies
on photosynthetic systems are scarce. In this study we investigated the dynamic characteristics of Photosystem II (PSII) membrane
fragments between 280 and 340 K, i.e., in the physiological temperature range and in the range of thermal denaturation of
some of the protein complexes. The mean square displacement values revealed the presence of a hydration-sensitive transition
in the sample between 310 and 320 K, suggesting that the oxygen evolving complex (OEC) plays an important role in the transition.
Indeed, in samples in which the OEC had been removed by TRIS- or heat-treatments (323 and 333 K) no such transition was found.
Further support on the main role of OEC in these reorganizations is provided by data obtained from differential scanning calorimetry
experiments, showing marked differences between the untreated and TRIS-treated samples. In contrast, circular dichroism spectra
exhibited only minor changes in the excitonic interactions below 323 K, showing that the molecular organization of the pigment-protein
complexes remains essentially unaffected. Our data, along with earlier incoherent neutron scattering data on PSII membranes
at cryogenic temperatures (Pieper et al., Biochemistry 46:11398–11409, 2007), demonstrate that this technique can be applied to characterize the dynamic features of PSII membranes, and can be used
to investigate photosynthetic membranes under physiologically relevant experimental conditions.
Content Type Journal Article
Category Regular Paper
Pages 1-12
DOI 10.1007/s11120-011-9701-x
Authors
Gergely Nagy, Institut Laue-Langevin, P.O. Box 156, 38042 Grenoble Cedex 9, France
Jörg Pieper, Institute of Physics, University of Tartu, Riia 142, 51014 Tartu, Estonia
Sashka B. Krumova, Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, G. Bontchev Str., bl. 21, 1113 Sofia, Bulgaria
László Kovács, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged, P.O. Box 521, 6701 Hungary
Marcus Trapp, Institut Laue-Langevin, P.O. Box 156, 38042 Grenoble Cedex 9, France
Gy?z? Garab, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged, P.O. Box 521, 6701 Hungary
Conventional linear and time-resolved spectroscopic techniques are often not appropriate to elucidate specific pigment–pigment
interactions in light-harvesting pigment-protein complexes (LHCs). Nonlinear (laser-) spectroscopic techniques, including
nonlinear polarization spectroscopy in the frequency domain (NLPF) as well as step-wise (resonant) and simultaneous (non-resonant) two-photon excitation spectroscopies may be advantageous in this regard. Nonlinear spectroscopies have been
used to elucidate substructure(s) of very complex spectra, including analyses of strong excitonic couplings between chlorophylls
and of interactions between (bacterio)chlorophylls and “optically dark” states of carotenoids in LHCs, including the major
antenna complex of higher plants, LHC II. This article shortly reviews our previous study and outlines perspectives regarding
the application of selected nonlinear laser-spectroscopic techniques to disentangle structure–function relationships in LHCs
and other pigment-protein complexes.
Content Type Journal Article
Category Review
Pages 1-9
DOI 10.1007/s11120-011-9700-y
Authors
Heiko Lokstein, Institut für Biochemie und Biologie/Pflanzenphysiologie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Haus 20, 14476 Potsdam-Golm, Germany
Alexander Betke, Institut für Physik und Astronomie/Photonik, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Haus 28, 14476 Potsdam-Golm, Germany
Maria Krikunova, Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany
Klaus Teuchner, Institut für Physik und Astronomie/Photonik, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Haus 28, 14476 Potsdam-Golm, Germany
Bernd Voigt, Institut für Physik und Astronomie/Photonik, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Haus 28, 14476 Potsdam-Golm, Germany
The multiexponential fluorescence decay of the CP29 complex in which the apoprotein and pigments were reconstituted in vitro
was examined. Of the three decay components observed only the two dominant ones, with about 3 and 5 ns lifetimes, were studied.
The main question addressed was whether the multicomponent decay was associated with sample optical heterogeneity. To this
end, we examined the optical absorption and fluorescence of the CP29 sample by means of two different and independent experimental
strategies. This approach was used as the wavelength positions of the absorption/fluorescence spectral forms has recently
been shown to be a sensitive indicator of the binding site-induced porphyrin ring deformation (Zucchelli et al. Biophys J
93:2240–2254, 2007) and hence of apoprotein conformational changes. The data indicate that this CP29 sample is optically homogeneous. It is
hypothesised that the different lifetimes are explained in terms of multiple detergent/CP29 interactions leading to different
quenching states, a suggestion that allows for optical homogeneity.
Content Type Journal Article
Category Regular Paper
Pages 1-10
DOI 10.1007/s11120-011-9696-3
Authors
Erica Belgio, CNR-Istituto di Biofisica, Sede di Milano, Via G. Celoria 26, 20133 Milan, Italy
Giorgio Tumino, CNR-Istituto di Biofisica, Sede di Milano, Via G. Celoria 26, 20133 Milan, Italy
Stefano Santabarbara, CNR-Istituto di Biofisica, Sede di Milano, Via G. Celoria 26, 20133 Milan, Italy
Giuseppe Zucchelli, CNR-Istituto di Biofisica, Sede di Milano, Via G. Celoria 26, 20133 Milan, Italy
Robert Jennings, CNR-Istituto di Biofisica, Sede di Milano, Via G. Celoria 26, 20133 Milan, Italy
The trimeric fucoxanthin–chlorophyll a/c protein (FCP) was purified from a Japanese brown alga, Cladosiphon okamuranus TOKIDA. Its pigment stoichiometry was determined to be chlorophyll (Chl) a:Chl c1:Chl c2:fucoxanthin = 4.6:1.1:1.0:5.5 by a combination of binary HPLC and 1H NMR spectroscopy. No violaxanthin found bound to the FCP. The ratio of Chl c/Chl a in this FCP is amongst the highest so far reported.
Content Type Journal Article
Category Regular Paper
Pages 1-8
DOI 10.1007/s11120-011-9698-1
Authors
Ritsuko Fujii, The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
Mamiko Kita, CREST/JST, 4-1-8 Hon-cho Kawaguchi, Saitama, 332-0012 Japan
Matsumi Doe, The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
Yoshiro Iinuma, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Naohiro Oka, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Yuki Takaesu, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Tomonori Taira, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Masahiko Iha, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Tadashi Mizoguchi, Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
Richard J. Cogdell, Glasgow Biomedical Research Centre, University of Glasgow, 12 University Place, Glasgow, G12 8QQ Scotland, UK
Hideki Hashimoto, The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
Diatoms possess effective photoprotection mechanisms, which may involve reorganizations in the photosynthetic machinery. We
have shown earlier, by using circular dichroism (CD) spectroscopy, that in Phaeodactylum tricornutum the pigment–protein complexes are arranged into chiral macrodomains, which have been proposed to be associated with the multilamellar
organization of the thylakoid membranes and shown to be capable of undergoing light-induced reversible reorganizations (Szabó
et al. Photosynth Res 95:237, 2008). Recently, by using small-angle neutron scattering (SANS) on the same algal cells we have determined the repeat distances
and revealed reversible light-induced reorganizations in the lamellar order of thylakoids (Nagy et al. Biochem J 436:225,
2011). In this study, we show that in moderately heat-treated samples, the weakening of the lamellar order is accompanied by the
diminishment of the psi-type CD signal associated with the long-range chiral order of the chromophores (psi, polymer or salt-induced).
Further, we show that the light-induced reversible increase in the psi-type CD is associated with swelling in the membrane
system, with magnitudes larger in high light than in low light. In contrast, shrinkage of the membrane system, induced by
sorbitol, brings about a decrease in the psi-type CD signal; this shrinkage also diminishes the non-photochemical quenching
capability of the cells. These data shed light on the origin of the psi-type CD signal, and confirm that both CD spectroscopy
and SANS provide valuable information on the macro-organization of the thylakoid membranes and their dynamic properties; these
parameters are evidently of interest with regard to the photoprotection in whole algal cells.
Content Type Journal Article
Category Regular Paper
Pages 1-9
DOI 10.1007/s11120-011-9693-6
Authors
Gergely Nagy, Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, Budapest, 1215 Hungary
Milán Szabó, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701 Hungary
Renáta Ünnep, Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, Budapest, 1215 Hungary
György Káli, Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, Budapest, 1215 Hungary
Yuliya Miloslavina, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701 Hungary
Petar H. Lambrev, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701 Hungary
Ottó Zsiros, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, Szeged, 6701 Hungary
A chlorophyll c binding membrane intrinsic light-harvesting complex, the fucoxanthin-chlorophyll a/c protein (FCP), was isolated from cultured discoid germilings of an edible Japanese brown alga, Cladosiphon (C.) okamuranus TOKIDA (Okinawa Mozuku in Japanese). The discoid germiling is an ideal source of brown algal photosynthetic pigment-protein
complexes in terms of its size and easiness of cultivation on a large scale. Ion-exchange chromatography was crucial for the
purification of FCP from solubilized thylakoid proteins. The molecular weight of the purified FCP assembly was estimated to
be ~56 kDa using blue native-PAGE. Further subunit analyses using 2D-PAGE revealed that the FCP assembled as a trimer consisting
of two distinguishable subunits having molecular weights of 18.2 (H) and 17.5 (L) kDa. Fluorescence and fluorescence-excitation
spectra confirmed that the purified FCP assembly was functionally intact.
Content Type Journal Article
Category Regular Paper
Pages 1-7
DOI 10.1007/s11120-011-9688-3
Authors
Ritsuko Fujii, The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585 Japan
Mamiko Kita, CREST/JST, 4-1-8 Hon-cho Kawaguchi, Saitama, 332-0012 Japan
Yoshiro Iinuma, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Naohiro Oka, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Yuki Takaesu, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Tomonori Taira, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Masahiko Iha, South Product Co. Ltd, 12-75 Suzaki, Uruma, Okinawa, 904-2234 Japan
Richard J. Cogdell, Glasgow Biomedical Research Centre, University of Glasgow, 12 University Place, Glasgow, G12 8QQ Scotland, UK
Hideki Hashimoto, The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585 Japan
In two recent studies, energy transfer was reported in certain phthalocyanine–carotenoid dyads between the optically forbidden
first excited state of carotenoids (Car S1) and phthalocyanines (Pcs) in the direction Pc ? Car S1 (Kloz et al., J Am Chem Soc 133:7007–7015, 2011) as well as in the direction Car S1 ? Pc (Liao et al., J Phys Chem A 115:4082–4091, 2011). In this article, we show that the extent of this energy transfer in both directions is closely correlated in these dyads.
This correlation and the additional observation that Car S1 is instantaneously populated after Pc excitation provides evidence that in these compounds excitonic interactions can occur.
Besides pure energy transfer and electron transfer, this is the third type of tetrapyrrole–carotenoid interaction that has
been shown to occur in these model compounds and that has previously been proposed as a photosynthetic regulation mechanism.
We discuss the implications of these models for photosynthetic regulation. The findings are also discussed in the context
of a model in which both electronic states are disordered and in which the strength of the electronic coupling determines
whether energy transfer, excitonic coupling, or electron transfer occurs.
Content Type Journal Article
Category Review
Pages 1-7
DOI 10.1007/s11120-011-9690-9
Authors
Pen-Nan Liao, Department for Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig, Germany
Smitha Pillai, Department of Chemistry & Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, AZ 85287-1604, USA
Miroslav Kloz, Biophysics Section, Departments of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081HV Amsterdam, The Netherlands
Devens Gust, Department of Chemistry & Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, AZ 85287-1604, USA
Ana L. Moore, Department of Chemistry & Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, AZ 85287-1604, USA
Thomas A. Moore, Department of Chemistry & Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, AZ 85287-1604, USA
John T. M. Kennis, Biophysics Section, Departments of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081HV Amsterdam, The Netherlands
Rienk van Grondelle, Biophysics Section, Departments of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081HV Amsterdam, The Netherlands
Peter J. Walla, Department for Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig, Germany
The Poisson-TrEsp method (where TrEsp stands for transition charges from electrostatic potentials) has been successfully applied
to calculate excitonic couplings in a variety of pigment–protein complexes. It relies on an isomorphism that allows for relating
the excitonic coupling between transition densities in dielectric media to their Coulomb coupling. This isomorphism was derived
by Hsu et al. (J. Chem. Phys. 114, 3065, (2001)) using time-dependent density functional response theory. In this article,
we provide an alternative and simple derivation by first-order perturbation theory. An application of Poisson-TrEsp to photosystem
I trimers reveals that the local field correction/screening factor depends on the mutual orientation of the pigments and on
the dielectric boundaries rather than on distance. A mean correction factor of f = 0.69 is determined for this system.
Content Type Journal Article
Category Regular Paper
Pages 1-6
DOI 10.1007/s11120-011-9685-6
Authors
Thomas Renger, Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040 Linz, Austria
Frank Müh, Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040 Linz, Austria
The temperature-dependent disassembly process of three monomeric isoforms, namely Lhcb1, Lhcb2, and Lhcb3, of the major light-harvesting
chlorophyll (Chl) a/b complexes of photosystem II (LHCIIb) were characterized by observing the changes of absorption spectra, circular dichroism
(CD), and dissociation processes of the bound pigments to the in vitro reconstituted complexes subjected to high temperatures.
Our results suggest that the three isoforms of LHCIIb undergo conformational rearrangements, structural changes, and dissociations
of the bound pigments when the ambient temperature increases from 20 to 90°C. The conformation of the complexes changed sensitively
to the changing temperatures because the absorption peaks in the Soret region (436 and 471 nm) and the Qy region (650–660
and 680 nm) decreased immediately upon elevating the ambient temperatures. Analyzing temperature-dependent denaturing and
pigment dissociation process, we can divide the disassembly process into three stages: The first stage, appeared from 20°C
to around 50–60°C, was characterized by the diminishment of the absorption around 650–660 and 680 nm, accompanied by the blue-shift
of the peak at 471 nm and disappearance of the absorbance at 436 nm, which is related to changes in the transition energy
of the Chl b cluster, and the red-most Chl a cluster in the LHCIIb. The second stage, beginning at about 50–60°C, was signified by the diminishment of the CD signal between
(+)483 nm and (?)490 nm, which implied the disturbance of dipole–dipole interaction of pigments, and the onset of the pigment
dissociation. The last stage, beginning at about 70–80°C, indicates the complete dissociation of the pigments from the complex.
The physiological aspects of the three stages in the denaturing process are also discussed.
Content Type Journal Article
Category Regular Paper
Pages 1-9
DOI 10.1007/s11120-011-9677-6
Authors
Yajie Zhang, Key Laboratory of Photobiology; Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing, 100093 China
Cheng Liu, Key Laboratory of Photobiology; Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing, 100093 China
Chunhong Yang, Key Laboratory of Photobiology; Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing, 100093 China
Light energy harvested by the pigments in Photosystem I (PSI) is used for charge separation in the reaction center (RC), after
which the positive charge resides on a special chlorophyll dimer called P700. In studies on the PSI trapping kinetics, P700+ is usually chemically reduced to re-open the RCs. So far, the information available about the reduction rate and possible
chlorophyll fluorescence quenching effects of these reducing agents is limited. This information is indispensible to estimate
the fraction of open RCs under known experimental conditions. Moreover, it would be important to understand if these reagents
have a chlorophyll fluorescence quenching effects to avoid the introduction of exogenous singlet excitation quenching in the
measurements. In this study, we investigated the effect of the commonly used reducing agent phenazine methosulfate (PMS) on
the RC and fluorescence emission of higher plant PSI–LHCI. We measured the P700+ reduction rate for different PMS concentrations, and show that we can give a reliable estimation on the fraction of closed
RCs based on these rates. The data show that PMS is quenching chlorophyll fluorescence emission. Finally, we determined that
the fluorescence quantum yield of PSI with closed RCs is 4% higher than if the RCs are open.
Content Type Journal Article
Category Regular Paper
Pages 1-7
DOI 10.1007/s11120-011-9671-z
Authors
Emilie Wientjes, Department of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
Roberta Croce, Department of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
This short review describes how solid-state NMR has provided a mechanistic and electronic picture of pigment–protein and pigment–pigment
interactions in photosynthetic antenna complexes. NMR results on purple bacterial antenna complexes show how the packing of
the protein and the pigments inside the light-harvesting oligomers induces mutual conformational stress. The protein scaffold
produces deformation and electrostatic polarization of the BChl macrocycles and leads to a partial electronic charge transfer
between the BChls and their coordinating histidines, which can tune the light-harvesting function. In chlorosome antennae
assemblies, the NMR template structure reveals how the chromophores can direct their self-assembly into higher macrostructures
which, in turn, tune the light-harvesting properties of the individual molecules by controlling their disorder, structural
deformation, and electronic polarization without the need for a protein scaffold. These results pave the way for addressing
the next challenge, which is to resolve the functional conformational dynamics of the lhc antennae of oxygenic species that allows them to switch between light-emitting and light-energy dissipating states.
Content Type Journal Article
Category Review
Pages 1-8
DOI 10.1007/s11120-011-9674-9
Authors
Anjali Pandit, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
Huub J. M. de Groot, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
Chlorosomes, the light-harvesting antennae of green photosynthetic bacteria, are based on large aggregates of bacteriochlorophyll
molecules. Aggregates with similar properties to those in chlorosomes can also be prepared in vitro. Several agents were shown
to induce aggregation of bacteriochlorophyll c in aqueous environments, including certain lipids, carotenes, and quinones. A key distinguishing feature of bacteriochlorophyll
c aggregates, both in vitro and in chlorosomes, is a large (>60 nm) red shift of their Qy absorption band compared with that of the monomers. In this study, we investigate the self-assembly of bacteriochlorophyll
c with the xanthophyll astaxanthin, which leads to the formation of a new type of complexes. Our results indicate that, due
to its specific structure, astaxanthin molecules competes with bacteriochlorophylls for the bonds involved in the aggregation,
thus preventing the formation of any significant red shift compared with pure bacteriochlorophyll c in aqueous buffer. A strong interaction between both the types of pigments in the developed assemblies, is manifested by
a rather efficient (~40%) excitation energy transfer from astaxanthin to bacteriochlorophyll c, as revealed by fluorescence excitation spectroscopy. Results of transient absorption spectroscopy show that the energy transfer
is very fast (<500 fs) and proceeds through the S2 state of astaxanthin.
Content Type Journal Article
Category Regular Paper
Pages 1-12
DOI 10.1007/s11120-011-9670-0
Authors
J. Alster, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Praha, Czech Republic
T. Polívka, Institute of Physical Biology, University of South Bohemia, Zámek 136, 373 33 Nové Hrady, Czech Republic
J. B. Arellano, Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC), Apdo. 257, 37071 Salamanca, Spain
P. H?íbek, Institute of Physical Biology, University of South Bohemia, Zámek 136, 373 33 Nové Hrady, Czech Republic
F. Vácha, Institute of Physical Biology, University of South Bohemia, Zámek 136, 373 33 Nové Hrady, Czech Republic
J. Hála, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Praha, Czech Republic
J. Pšen?ík, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Praha, Czech Republic
Single complex fluorescence polarization spectroscopy is applied to study the peripheral light harvesting antenna (LH2) from
photosynthetic purple bacterium Rhodopseudomonas (Rps.) acidophila. The measured two-dimensional excitation-emission polarization plots are used to construct geometric representation for the
absorbing B800 and emitting B850 as ellipses. The shape and orientation of the ellipses is discussed in terms of tilted LH2
complexes where emission occurs from energetically disordered B850 excitons.
Content Type Journal Article
Category Regular Paper
Pages 1-5
DOI 10.1007/s11120-011-9676-7
Authors
Sumera Tubasum, Department of Chemical Physics, Lund University, Lund, Sweden
Daniel Thomsson, Department of Chemical Physics, Lund University, Lund, Sweden
Richard Cogdell, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, UK
Ivan Scheblykin, Department of Chemical Physics, Lund University, Lund, Sweden
Tõnu Pullerits, Department of Chemical Physics, Lund University, Lund, Sweden
The PufX protein, encoded by the pufX gene of Rhodobacter sphaeroides, plays a key role in the organization and function of the core antenna (LH1)-reaction centre (RC) complex, which collects
photons and triggers primary photochemical reactions. We synthesized a PufX/maltose-binding protein (MBP) fusion protein to
study the effect of the PufX protein on the reconstitution of B820 subunit-type and LH1-type complexes. The fusion protein
was synthesized using an Escherichia coli expression system and purified by affinity chromatography. Reconstitution experiments demonstrated that the MBP-PufX protein
destabilizes the subunit-type complex (20°C), consistent with previous reports. Interestingly, however, the preformed LH1-type
complex was stable in the presence of MBP-PufX. The MBP-PufX protein did not influence the preformed LH1-type complexes (4°C).
The LH1-type complex containing MBP-PufX showed a unique temperature-dependent structural transformation that was irreversible.
The predominant form of the complex at 4°C was the LH1-type. When shifted to 20°C, subunit-type complexes became predominant.
Upon subsequent cooling back to 4°C, instead of re-forming the LH1-type complexes, the predominant form remained the subunit-type
complexes. In contrast, reversible transformation of LH1 (4°C) and subunit-type complexes (20°C) occurs in the absence of
PufX. These results are consistent with the suggestion that MBP-PufX interacts with the LH1?- polypeptide in the subunit (?/?)-type
complex (at 20°C), preventing oligomerization of the subunit to form LH1-type complexes.
Content Type Journal Article
Category Regular Paper
Pages 1-7
DOI 10.1007/s11120-011-9673-x
Authors
Shunnsuke Sakai, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555 Japan
Akito Hiro, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555 Japan
Masaharu Kondo, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555 Japan
Toshihisa Mizuno, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555 Japan
Toshiki Tanaka, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555 Japan
Takehisa Dewa, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555 Japan
Mamoru Nango, The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585 Japan
The linear optical spectra (absorbance, linear dichroism, circular dichroism, fluorescence) of the CP43 (PsbC) antenna of
the photosystem II core complex (PSIIcc) pertaining to the S0 ? S1 (QY) transitions of the chlorophyll (Chl) a pigments are simulated by applying a combined quantum chemical/electrostatic method to obtain excitonic couplings and local
transition energies (site energies) on the basis of the 2.9 Å resolution crystal structure (Guskov et al., Nat Struct Mol
Biol 16:334–342, 2009). The electrostatic calculations identify three Chls with low site energies (Chls 35, 37, and 45 in the nomenclature of Loll
et al. (Nature 438:1040–1044, 2005). A refined simulation of experimental spectra of isolated CP43 suggests a modified set of site energies within 143 cm?1 of the directly calculated values (root mean square deviation: 80 cm?1). In the refined set, energy sinks are at Chls 37, 43, and 45 in agreement with earlier fitting results (Raszewski and Renger,
J Am Chem Soc 130:4431–4446, 2008). The present structure-based simulations reveal that a large part of the redshift of Chl 37 is due to a digalactosyldiacylglycerol
lipid. This finding suggests a new role for lipids in PSIIcc, namely the tuning of optical spectra and the creation of an
excitation energy funnel towards the reaction center. The analysis of electrostatic pigment–protein interactions is used to
identify amino acid residues that are of potential interest for an experimental approach to an assignment of site energies
and energy sinks by site-directed mutagenesis.
Content Type Journal Article
Category Regular Paper
Pages 1-15
DOI 10.1007/s11120-011-9675-8
Authors
Frank Müh, Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040 Linz, Austria
Mohamed El-Amine Madjet, Center for Free-Electron Laser Science/DESY, Notkestr. 85, 22607 Hamburg, Germany
Thomas Renger, Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040 Linz, Austria
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.
Content Type Journal Article
Category Regular Paper
Pages 1-8
DOI 10.1007/s11120-011-9669-6
Authors
Yueyong Xin, Departments of Biology and Chemistry, Washington University, St. Louis, MO 63130, USA
Jie Pan, The Biodesign Institute at Arizona State University, Arizona State University, Tempe, AZ 85287, USA
Aaron M. Collins, Departments of Biology and Chemistry, Washington University, St. Louis, MO 63130, USA
Su Lin, The Biodesign Institute at Arizona State University, Arizona State University, Tempe, AZ 85287, USA
Robert E. Blankenship, Departments of Biology and Chemistry, Washington University, St. Louis, MO 63130, USA
Small-angle neutron scattering (SANS) and dynamic light scattering (DLS) have been employed in studying the structural information
of various biological systems, particularly in systems without high-resolution structural information available. In this report,
we briefly present some principles and biological applications of neutron scattering and DLS, compare the differences in information
that can be obtained with small-angle X-ray scattering (SAXS), and then report recent studies of SANS and DLS, together with
other biophysical approaches, for light-harvesting antenna complexes and reaction centers of purple and green phototrophic
bacteria.
Content Type Journal Article
Category Review
Pages 1-13
DOI 10.1007/s11120-011-9665-x
Authors
Kuo-Hsiang Tang, Department of Biology and Department of Chemistry, Washington University in St. Louis, Campus Box 1137, St. Louis, MO 63130, USA
Robert E. Blankenship, Department of Biology and Department of Chemistry, Washington University in St. Louis, Campus Box 1137, St. Louis, MO 63130, USA
In photosynthesis research, circular dichroism (CD) spectroscopy is an indispensable tool to probe molecular architecture
at virtually all levels of structural complexity. At the molecular level, the chirality of the molecule results in intrinsic
CD; pigment–pigment interactions in protein complexes and small aggregates can give rise to excitonic CD bands, while “psi-type”
CD signals originate from large, densely packed chiral aggregates. It has been well established that anisotropic CD (ACD),
measured on samples with defined non-random orientation relative to the propagation of the measuring beam, carries specific
information on the architecture of molecules or molecular macroassemblies. However, ACD is usually combined with linear dichroism
and can be distorted by instrumental imperfections, which given the strong anisotropic nature of photosynthetic membranes
and complexes, might be the reason why ACD is rarely studied in photosynthesis research. In this study, we present ACD spectra,
corrected for linear dichroism, of isolated intact thylakoid membranes of granal chloroplasts, washed unstacked thylakoid
membranes, photosystem II (PSII) membranes (BBY particles), grana patches, and tightly stacked lamellar macroaggregates of
the main light-harvesting complex of PSII (LHCII). We show that the ACD spectra of face- and edge-aligned stacked thylakoid
membranes and LHCII lamellae exhibit profound differences in their psi-type CD bands. Marked differences are also seen in
the excitonic CD of BBY and washed thylakoid membranes. Magnetic CD (MCD) spectra on random and aligned samples, and the largely
invariable nature of the MCD spectra, despite dramatic variations in the measured isotropic and anisotropic CD, testify that
ACD can be measured without substantial distortions and thus employed to extract detailed information on the (supra)molecular
organization of photosynthetic complexes. An example is provided showing the ability of CD data to indicate such an organization,
leading to the discovery of a novel crystalline structure in macroaggregates of LHCII.
Content Type Journal Article
Category Regular Paper
Pages 1-11
DOI 10.1007/s11120-011-9664-y
Authors
Yuliya Miloslavina, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, 6701 Szeged, Hungary
Petar H. Lambrev, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, 6701 Szeged, Hungary
Tamás Jávorfi, Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Chilton, Didcot, OX11 0DE UK
Zsuzsanna Várkonyi, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, 6701 Szeged, Hungary
Václav Karlický, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, 6701 Szeged, Hungary
Joseph S. Wall, Biology Department, Brookhaven National Laboratory, Upton, NY, USA
Geoffrey Hind, Biology Department, Brookhaven National Laboratory, Upton, NY, USA
Gy?z? Garab, Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, 6701 Szeged, Hungary
In this study, gene sequences coding for the light-harvesting (LH) 2 polypeptides from a thermophilic purple sulfur bacterium
Thermochromatiumtepidum are reported and characterization of the LH2 complex is described. Three sets of pucBA genes have been identified, and the gene products have been analyzed by electrophoresis and reversed-phase chromatography.
The result shows that all of the genes are expressed but the distribution of the expression is not uniform. The gene products
undergo post-translational modification, where two of the ?-polypeptides appear to be N-terminally methylated. Absorption
spectrum of the purified LH2 complex exhibits Qy transitions at 800 and 854 nm in dodecyl ?-maltopyranoside solution, and the circular dichroism spectrum shows a “molischianum”-like
characteristic. No spectral change was observed for the LH2 when the bacterium was cultured under different conditions of
light intensity. In lauryl dimethylamine N-oxide (LDAO) solution, significant changes in the absorption spectrum were observed. The B850 peak decreased and blue-shifted
with increasing the LDAO concentration, whereas the B800 intensity increased without change in the peak position. The spectral
changes can be partially or almost completely reversed by addition of metal ions, and the divalent cations seem to be more
effective. The results indicate that ionic interactions may exist between LH2, detergent molecules and metal ions. Possible
mechanisms involved in the detergent- and cation-induced spectral changes are discussed.
Content Type Journal Article
Category Regular Paper
Pages 1-10
DOI 10.1007/s11120-011-9658-9
Authors
Fumie Sekine, Faculty of Science, Ibaraki University, Mito, 310-8512 Japan
Kentaro Horiguchi, Faculty of Science, Ibaraki University, Mito, 310-8512 Japan
Yasuhiro Kashino, Graduate School and Faculty of Science, University of Hyogo, 3-2-1 Kohto, Ako-gun, Hyogo 678-1297, Japan
Yuuki Shimizu, Faculty of Science, Ibaraki University, Mito, 310-8512 Japan
Long-Jiang Yu, Faculty of Science, Ibaraki University, Mito, 310-8512 Japan
Masayuki Kobayashi, Ariake National College of Technology, Omuta, Fukuoka 836-8585, Japan
Zheng-Yu Wang, Faculty of Science, Ibaraki University, Mito, 310-8512 Japan
During the last years significant progress was achieved in unraveling molecular characteristics of the thylakoid membrane
of different diatoms. With the present review it is intended to summarize the current knowledge about the structural and functional
changes within the thylakoid membrane of diatoms acclimated to different light conditions. This aspect is addressed on the
level of the organization and regulation of light-harvesting proteins, the dissipation of excessively absorbed light energy
by the process of non-photochemical quenching, and the lipid composition of diatom thylakoid membranes. Finally, a working
hypothesis of the domain formation of the diatom thylakoid membrane is presented to highlight the most prominent differences
of heterokontic thylakoids in comparison to vascular plants and green algae during the acclimation to low and high light conditions.
Content Type Journal Article
Category Review
Pages 1-13
DOI 10.1007/s11120-011-9633-5
Authors
Bernard Lepetit, CNRS UMR6250 ‘LIENSs’, Institute for Coastal and Environmental Research (ILE), University of La Rochelle, 2 rue Olympe de Gouges, 17042 La Rochelle cedex, France
Reimund Goss, Department of Plant Physiology, Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
Torsten Jakob, Department of Plant Physiology, Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
Christian Wilhelm, Department of Plant Physiology, Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
Methyl pheophorbide-a/a? derivatives covalently linked with oligomethylene chains at the 3-CH2OCO– and 132-COO– moieties in a molecule were prepared by modifying chlorophyll-a through intramolecular ring-closing metathesis of vinyl groups. At least, a C10-length between the 33- and 134-positions was necessary for the cyclization and connection of a C12-strap was the most suitable to achieve the highest closure
yield. The oligomethylene chain in 132R-epimers derived from methyl pheophorbide-a covered the ?-face of the chlorin ?-plane and the strap in the corresponding 132S-epimers protected the ?-face. Synthetic 132R-epimer with a dodecamethylene chain gave a flat chlorin ?-plane, while the decamethylene chain in the 132R-epimer distorted the ?-system due to its shorter linkage. The distortion by strapping in the 132R-epimer induced a slight blue-shift of Qy peak in dichloromethane. CD spectra of the 132R-epimers were similarly dependent on the chain length, i.e., the distortion of ?-plane. Visible absorption and CD spectra
of all the strapped 132S-epimers were almost identical and only slightly different from those of the unstrapped. The strapping in the 132S-epimers shifted the Qy peak bathochromically.
Content Type Journal Article
Category Regular Paper
Pages 1-8
DOI 10.1007/s11120-010-9616-y
Authors
Hitoshi Tamiaki, Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
Hiroshi Takebe, Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
Shin-ichi Sasaki, Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
Yumiko Kataoka, Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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