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beruecksichtige naturwissenschaftliche Journale:
Photosynthesis Research - published by
Springer -
... is an international journal open to papers of merit dealing with both basic and applied aspects of photosynthesis. It covers all aspects of photosynthesis research, including, but not limited to, light absorption and emission, excitation energy transfer, primary photochemistry, model systems, membrane components, protein complexes, electron transport, photophosphorylation, carbon assimilation, regulatory phenomena, molecular biology, environmental and ecological aspects, photorespiration, and bacterial and algal photosynthesis.
Aktuelle wissenschaftliche Fachartikel der
genannten Journale:
Abstract The large family of light-harvesting-like proteins contains members with one to four membrane spanning helices with significant
homology to the chlorophyll a/b-binding antenna proteins of plants. From structural as well as evolutionary perspective, it is likely that the members of
this family bind chlorophylls and carotenoids. However, undisputable evidence is still lacking. The cyanobacterial small CAB-like
proteins (SCPs) are one-helix proteins with compelling similarity to the first and third transmembrane helix of LHCII (LHCIIb)
including the chlorophyll-binding motifs. They have been proposed to act as chlorophyll-carrier proteins. Here, we analyze
the in vivo absorption spectra of single scp deletion mutants in Synechocystis sp. PCC 6803 and compare the in vitro pigment binding ability of the SCP pairs ScpC/D and ScpB/E with the one of LHCII and
a synthetic peptide containing the chlorophyll-binding motif (Eggink LL, Hoober JK (2000) J Biol Chem 275:9087–9090). We demonstrate
that deletion of scpB alters the pigmentation in the cyanobacterial cell. Furthermore, we are able to show that chlorophylls and carotenoids interact
in vitro with the pairs of ScpC/D and ScpB/E, demonstrated by fluorescence resonance energy transfer and circular dichroism.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9368-0
Authors
Patrik Storm, Umeå University Department of Chemistry and Umeå Plant Science Centre 901 87 Umeå Sweden
Miguel A. Hernandez-Prieto, Umeå University Department of Chemistry and Umeå Plant Science Centre 901 87 Umeå Sweden
Laura L. Eggink, Arizona State University Faculty of Biomedicine and Biotechnology, School of Life Sciences P.O. Box 874501 Tempe AZ 85287-4501 USA
J. Kenneth Hoober, Arizona State University Faculty of Biomedicine and Biotechnology, School of Life Sciences P.O. Box 874501 Tempe AZ 85287-4501 USA
Christiane Funk, Umeå University Department of Chemistry and Umeå Plant Science Centre 901 87 Umeå Sweden
Abstract Solar power is the most abundant source of renewable energy. In this respect, the goal of making photoactive proteins is to
utilize this energy to generate an electron flow. Photosystems have provided the blueprint for making such systems, since
they are capable of converting the energy of light into an electron flow using a series of redox cofactors. Protein tunes
the redox potential of the cofactors and arranges them such that their distance and orientation are optimal for the creation
of a stable charge separation. The aim of this review is to present an overview of the literature with regard to some elegant
functional structures that protein designers have created by introducing cofactors and photoactivity into synthetic proteins.
Content Type Journal Article
Category Review
DOI 10.1007/s11120-008-9367-1
Authors
Reza Razeghifard, Nova Southeastern University Division of Math, Science, and Technology, Farquhar College of Arts & Science Fort Lauderdale FL 33314 USA
Abstract This review summarizes our current state of knowledge on the structural organization and functional pattern of photosynthetic
water splitting in the multimeric Photosystem II (PS II) complex, which acts as a light-driven water: plastoquinone-oxidoreductase.
The overall process comprises three types of reaction sequences: (1) photon absorption and excited singlet state trapping
by charge separation leading to the ion radical pair
formation, (2) oxidative water splitting into four protons and molecular dioxygen at the water oxidizing complex (WOC) with
\textP680 + ·
as driving force and tyrosine YZ as intermediary redox carrier, and (3) reduction of plastoquinone to plastoquinol at the special QB binding site with
\textQ\textA - ·
acting as reductant. Based on recent progress in structure analysis and using new theoretical approaches the mechanism of
reaction sequence (1) is discussed with special emphasis on the excited energy transfer pathways and the sequence of charge
transfer steps:
where 1(RC-PC)* denotes the excited singlet state 1P680* of the reaction centre pigment complex. The structure of the catalytic Mn4OXCa cluster of the WOC and the four step reaction sequence leading to oxidative water splitting are described and problems
arising for the electronic configuration, in particular for the nature of redox state S3, are discussed. The unravelling of the mode of O–O bond formation is of key relevance for understanding the mechanism of
the process. This problem is not yet solved. A multistate model is proposed for S3 and the functional role of proton shifts and hydrogen bond network(s) is emphasized. Analogously, the structure of the QB site for PQ reduction to PQH2 and the energetic and kinetics of the two step redox reaction sequence are described. Furthermore, the relevance of the protein
dynamics and the role of water molecules for its flexibility are briefly outlined. We end this review by presenting future
perspectives on the water oxidation process.
Content Type Journal Article
Category Review
DOI 10.1007/s11120-008-9345-7
Authors
Gernot Renger, Berlin Institute of Technology Max Volmer Laboratory for Biophysical Chemistry Berlin Germany
Thomas Renger, Free University Berlin Institute for Chemistry and Biochemistry Berlin Germany
Abstract Dissipation of excess absorbed light energy in eukaryotic photoautotrophs through zeaxanthin- and ΔpH-dependent photosystem
II antenna quenching is considered the major mechanism for non-photochemical quenching and photoprotection. However, there
is mounting evidence of a zeaxanthin-independent pathway for dissipation of excess light energy based within the PSII reaction
centre that may also play a significant role in photoprotection. We summarize recent reports which indicate that this enigma
can be explained, in part, by the fact that PSII reaction centres can be reversibly interconverted from photochemical energy
transducers that convert light into ATP and NADPH to efficient, non-photochemical energy quenchers that protect the photosynthetic
apparatus from photodamage. In our opinion, reaction centre quenching complements photoprotection through antenna quenching,
and dynamic regulation of photosystem II reaction centre represents a general response to any environmental condition that
predisposes the accumulation of reduced QA in the photosystem II reaction centres of prokaryotic and eukaryotic photoautotrophs. Since the evolution of reaction centres
preceded the evolution of light harvesting systems, reaction centre quenching may represent the oldest photoprotective mechanism.
Content Type Journal Article
Category Review
DOI 10.1007/s11120-008-9365-3
Authors
Alexander G. Ivanov, University of Western Ontario Department of Biology and The Biotron 1151 Richmond Street N. London ON Canada N6A 5B7
Prafullachandra V. Sane, Jain Irrigation Systems Limited Jain Hills Jalgaon 425001 India
Vaughan Hurry, Umeå University Umeå Plant Science Centre, Department of Plant Physiology 901 87 Umea Sweden
Gunnar Öquist, Umeå University Umeå Plant Science Centre, Department of Plant Physiology 901 87 Umea Sweden
Norman P. A. Huner, University of Western Ontario Department of Biology and The Biotron 1151 Richmond Street N. London ON Canada N6A 5B7
Abstract From a chemical point of view methanol is one of the closest analogues of water. Consistent with this idea EPR spectroscopy
studies have shown that methanol binds at—or at least very close to—the Mn4OxCa cluster of photosystem II (PSII). In contrast, Clark-type oxygen rate measurements demonstrate that the O2 evolving activity of PSII is surprisingly unaffected by methanol concentrations of up to 10%. Here we study for the first
time in detail the effect of methanol on photosynthetic water-splitting by employing a Joliot-type bare platinum electrode.
We demonstrate a linear dependence of the miss parameter for Si state advancement on the methanol concentrations in the range of 0–10% (v/v). This finding is consistent with the idea that
methanol binds in PSII with similar affinity as water to one or both substrate binding sites at the Mn4OxCa cluster. The possibility is discussed that the two substrate water molecules bind at different stages of the cycle, one
during the S4 → S0 and the other during the S2 → S3 transition.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9364-4
Authors
Birgit Nöring, Max-Planck-Institut für Bioanorganische Chemie Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
Dmitriy Shevela, Max-Planck-Institut für Bioanorganische Chemie Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
Gernot Renger, TU Berlin Max-Volmer Laboratorium für Biophysikalische Chemie Strasse des 17. Juni 135 Berlin Germany
Johannes Messinger, Max-Planck-Institut für Bioanorganische Chemie Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
Abstract The influence of the protein environment on the primary electron donor, P, a bacteriochlorophyll a dimer, of reaction centers from Rhodobacter sphaeroides, has been investigated using electron paramagnetic resonance and electron nuclear double resonance spectroscopy. These techniques
were used to probe the effects on P that are due to alteration of three amino acid residues, His L168, Asn L170, and Asn M199.
The introduction of Glu at L168, Asp at L170, or Asp at M199 changes the oxidation/reduction midpoint potential of P in a
pH-dependent manner (Williams et al. (2001) Biochemistry 40, 15403–15407). For the double mutant His L168 to Glu and Asn at L170 to Asp, excitation results in electron
transfer along the A-side branch of cofactors at pH 7.2, but at pH 9.5, a long-lived state involving B-side cofactors is produced
(Haffa et al. (2004) J Phys Chem B 108, 4–7). Using electron paramagnetic resonance spectroscopy, the mutants with alterations of each of the
three individual residues and a double mutant, with changes at L168 and L170, were found to have increased linewidths of 10.1–11.0 G
compared to the linewidth of 9.6 G for wild type. The Special TRIPLE spectra were pH dependent, and at pH 8, the introduction
of aspartate at L170 increased the spin density ratio, ρL/ρM, to 6.1 while an aspartate at the symmetry related position, M199, decreased the ratio to 0.7 compared to the value of 2.1
for wild type. These results indicate that the energy of the two halves of P changes by about 100 meV due to the mutations
and are consistent with the interpretation that electrostatic interactions involving these amino acid residues contribute
to the switch in pathway of electron transfer.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9346-6
Authors
J. P. Allen, Arizona State University Department of Chemistry and Biochemistry and Center for Bioenergy and Photosynthesis Tempe AZ 85287-1604 USA
J. M. Cordova, Arizona State University Department of Chemistry and Biochemistry and Center for Bioenergy and Photosynthesis Tempe AZ 85287-1604 USA
C. C. Jolley, Arizona State University Department of Chemistry and Biochemistry and Center for Bioenergy and Photosynthesis Tempe AZ 85287-1604 USA
T. A. Murray, Arizona State University Department of Chemistry and Biochemistry and Center for Bioenergy and Photosynthesis Tempe AZ 85287-1604 USA
J. W. Schneider, Arizona State University Department of Chemistry and Biochemistry and Center for Bioenergy and Photosynthesis Tempe AZ 85287-1604 USA
N. W. Woodbury, Arizona State University Department of Chemistry and Biochemistry and Center for Bioenergy and Photosynthesis Tempe AZ 85287-1604 USA
J. C. Williams, Arizona State University Department of Chemistry and Biochemistry and Center for Bioenergy and Photosynthesis Tempe AZ 85287-1604 USA
J. Niklas, Max-Planck-Institut für Bioanorganische Chemie Mülheim/Ruhr Germany
G. Klihm, Max-Planck-Institut für Bioanorganische Chemie Mülheim/Ruhr Germany
M. Reus, Max-Planck-Institut für Bioanorganische Chemie Mülheim/Ruhr Germany
W. Lubitz, Max-Planck-Institut für Bioanorganische Chemie Mülheim/Ruhr Germany
Abstract Extraction of Ca2+ from the O2-evolving complex (OEC) of photosystem II (PSII) membranes with 2 M NaCl in the light (PSII(–Ca/NaCl)) results in 90% inhibition
of the O2-evolution reaction. However, electron transfer from the donor to acceptor side of PSII, measured as the reduction of the
exogenous acceptor 2,6-dichlorophenolindophenol (DCIP) under continuous light, is inhibited by only 30%. Thus, calcium extraction
from the OEC inhibits the synthesis of molecular O2 but not the oxidation of a substrate we term X, the source of electrons for DCIP reduction. The presence of electron transfer
across PSII(–Ca/NaCl) membranes was demonstrated using fluorescence induction kinetics, a method that does not require an
artificial acceptor. The calcium chelator, EGTA (5 mM), when added to PSII(–Ca/NaCl) membranes, does not affect the inhibition
of O2 evolution by NaCl but does inhibit DCIP reduction up to 92% (the reason why electron transport in Ca2+-depleted materials has not been noticed before). Another chelator, sodium citrate (citrate/low pH method of calcium extraction),
also inhibits both O2 evolution and DCIP reduction. The role of all buffer components (including bicarbonate and sucrose) as possible sources of
electrons for PSII(–Ca/NaCl) membranes was investigated, but only the absence of chloride anions strongly inhibited the rate
of DCIP reduction. Substitution of other anions for chloride indicates that Cl− serves its well-known role as an OEC cofactor, but it is not substrate X. Multiple turnover flash experiments have shown
a period of four oscillations of the fluorescence yield (both the maximum level, Fmax, and the fluorescence level measured 50 s after an actinic flash in the presence of DCMU) in native PSII membranes, reflecting
the normal function of the OEC, but the absence of oscillations in PSII(–Ca/NaCl) samples. Thus, PSII(–Ca/NaCl) samples do
not evolve O2 but do transfer electrons from the donor to acceptor sides and exhibit a disrupted S-state cycle. We explain these results
as follows. In Ca2+-depleted PSII membranes, obtained without chelators, the oxidation of the OEC stops after the absorption of three quanta
of light (from the S1 state), which should convert the native OEC to the S4 state. An one-electron oxidation of the water
molecule bound to the Mn cluster then occurs (the second substrate water molecule is absent due to the absence of calcium),
and the OEC returns to the S3 state. The appearance of a sub-cycle within the S-state cycle between S3-like and S4-like states
supplies electrons (substrate X is postulated to be OH−), explains the absence of O2 production, and results in the absence of a period of four oscillation of the normal functional parameters, such as the fluorescence
yield or the EPR signal from S2. Chloride anions probably keep the redox potential of the Mn cluster low enough for its oxidation
by YZ•.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9347-5
Authors
Boris K. Semin, Lomonosov Moscow State University Department of Biophysics, Faculty of Biology 119991 Moscow Russia
Lira N. Davletshina, Lomonosov Moscow State University Department of Biophysics, Faculty of Biology 119991 Moscow Russia
Il’ya I. Ivanov, Lomonosov Moscow State University Department of Biophysics, Faculty of Biology 119991 Moscow Russia
Andrei B. Rubin, Lomonosov Moscow State University Department of Biophysics, Faculty of Biology 119991 Moscow Russia
Michael Seibert, National Renewable Energy Laboratory Chemical and Biosciences Center Golden CO 80401 USA
Abstract The functionality of photosystem II (PS II) following high-light pre-treatment of leaf segments at a chilling temperature
was monitored as Fv/Fm, the ratio of variable to maximum chlorophyll fluorescence in the dark-adapted state and a measure of the optimal photochemical
efficiency in PS II. Recovery of PS II functionality in low light (LL) and at a favourable temperature was retarded by (1)
water stress and (2) growth in LL, in both spinach and Alocasia macrorrhiza L. In spinach leaf segments, water stress per se affected neither Fv/Fm nor the ability of the adenosine triphosphate (ATP) synthase to be activated by far-red light for ATP synthesis, but it induced
chloroplast shrinkage as observed in frozen and fractured samples by scanning electron microscopy. A common feature of water
stress and growth of plants in LL is the enhanced anchoring of PS II complexes, either across the shrunken lumen in water-stress
conditions or across the partition gap in larger grana due to growth in LL. We suggest that such enhanced anchoring restricts
the mobility of PS II complexes in the thylakoid membrane system, and hence hinders the lateral migration of photoinactivated
PS II reaction centres to the stroma-located ribosomes for repair.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9363-5
Authors
Riichi Oguchi, The Australian National University Research School of Biological Sciences Canberra ACT 0200 Australia
Husen Jia, The Australian National University Research School of Biological Sciences Canberra ACT 0200 Australia
James Barber, Imperial College London Division of Molecular Biosciences, Faculty of Science London SW7 2AZ UK
Wah Soon Chow, The Australian National University Research School of Biological Sciences Canberra ACT 0200 Australia
Abstract Even prior to the publication of the crystal structures for photosystem II (PSII), it had already been suggested that water,
O2 and H+ channels exist in PSII to achieve directed transport of these molecules, and to avoid undesirable side reactions. Computational
efforts to uncover these channels and investigate their properties are still at early stages, and have so far only been based
on the static PSII structure. The rationale behind the proposals for such channels and the computer modelling studies thus
far are reviewed here. The need to take the dynamic protein into account is then highlighted with reference to the specific
issues and techniques applicable to the simulation of each of the three channels. In particular, lessons are drawn from simulation
studies on other protein systems containing similar channels.
Content Type Journal Article
Category REVIEW
DOI 10.1007/s11120-008-9358-2
Authors
Felix M. Ho, Uppsala University Department of Photochemistry and Molecular Science, The Ångström Laboratory P. O. Box 523 75120 Uppsala Sweden
Abstract Green sulfur bacteria (GSB) rely on the chlorosome, a light-harvesting apparatus comprised almost entirely of self-organizing
arrays of bacteriochlorophyll (BChl) molecules, to harvest light energy and pass it to the reaction center. In Chlorobaculum tepidum, over 97% of the total BChl is made up of a mixture of four BChl c homologs in the chlorosome that differ in the number and identity of alkyl side chains attached to the chlorin ring. C. tepidum has been reported to vary the distribution of BChl c homologs with growth light intensity, with the highest degree of BChl c alkylation observed under low-light conditions. Here, we provide evidence that this functional response at the level of the
chlorosome can be induced not only by light intensity, but also by temperature and a mutation that prevents phototrophic thiosulfate
oxidation. Furthermore, we show that in conjunction with these functional adjustments, the fraction of cellular volume occupied
by chlorosomes was altered in response to environmental conditions that perturb the balance between energy absorbed by the
light-harvesting apparatus and energy utilized by downstream metabolic reactions.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9361-7
Authors
Rachael M. Morgan-Kiss, Miami University Department of Microbiology Oxford OH 45045 USA
Leong-Keat Chan, University of Delaware Delaware Biotechnology Institute 15 Innovation Way Newark DE 19711 USA
Shannon Modla, University of Delaware Delaware Biotechnology Institute 15 Innovation Way Newark DE 19711 USA
Timothy S. Weber, University of Delaware Delaware Biotechnology Institute 15 Innovation Way Newark DE 19711 USA
Mark Warner, University of Delaware College of Marine and Earth Studies 700 Pilottown Road Lewes DE 19958 USA
Kirk J. Czymmek, University of Delaware Delaware Biotechnology Institute 15 Innovation Way Newark DE 19711 USA
Thomas E. Hanson, University of Delaware Delaware Biotechnology Institute 15 Innovation Way Newark DE 19711 USA
Abstract This abstract is a prologue to this paper. Prior to his health failing, Martin Gibbs began writing remembrances of his education
and beginning a science career, particularly on the peaceful uses of nuclear radiation, at the U.S. Brookhaven National Laboratory
(BNL), Camp Upton, NY. Two years before his death Martin provided one of us (Govindjee) a draft text narrating his science
beginnings in anticipation of publication in Photosynthesis Research. Govindjee edited his draft and returned it to him. Later, when it became difficult for him to complete it, he phoned Govindjee
and expressed the desire that Govindjee publish this story, provided he kept it close to his original. Certain parts of Martin’s
narrations have appeared without references (Gibbs 1999). The Gibbs family made a similar request since the narrations contained numerous early personal accounts. Clanton Black
recently presented an elegant tribute on Martin Gibbs and his entire science career (Black 2008). Clanton was given the draft, which he and Govindjee then agreed to finish. This chronicle is their effort to place Gibbs’s
narrations about his education and his maturation scientifically, in context with the beginnings of biological chemistry work
with carbon-14 at the BNL (see Gibbs 1999). Further, these events are placed in context with those times of newly discovered radioisotopes which became available as
part of the intensive nuclear research of World War II (WW II). Carbon-14, discovered during WW II nuclear research in 1940,
was extremely useful and quickly led to the rapid discovery of new carbon metabolism pathways and biochemical cycles, e.g.,
photosynthetic carbon assimilation, within a decade after WW II.
Content Type Journal Article
Category Historical
DOI 10.1007/s11120-008-9357-3
Authors
Clanton C. Black, University of Georgia Biochemistry & Molecular Biology Department, Fred C. Davison Life Sciences Complex Athens GA 30602 USA
Govindjee, University of Illinois Department of Plant Biology 265 Morrill Hall, 505 South Goodwin Avenue Urbana IL 61801 USA
Abstract The PsbP is a thylakoid lumenal subunit of photosystem II (PSII), which has developed specifically in higher plants and green
algae. In higher plants, the molecular function of PsbP has been intensively investigated by release–reconstitution experiments
in vitro. Recently, solution of a high-resolution structure of PsbP has enabled investigation of structure–function relationships,
and efficient gene-silencing techniques have demonstrated the crucial role of PsbP in PSII activity in vivo. Furthermore,
genomic and proteomic studies have shown that PsbP belongs to the divergent PsbP protein family, which consists of about 10
members in model plants such as Arabidopsis and rice. Characterization of the molecular function of PsbP homologs using Arabidopsis
mutants suggests that each plays a distinct and important function in maintaining photosynthetic electron transfer. In this
review, recent findings regarding the molecular functions of PsbP and other PsbP homologs in higher plants are summarized,
and the molecular evolution of these proteins is discussed.
Content Type Journal Article
Category Review
DOI 10.1007/s11120-008-9359-1
Authors
Kentaro Ifuku, Kyoto University Graduate School of Biostudies Kyoto 606–8502 Japan
Seiko Ishihara, Kyoto University Graduate School of Biostudies Kyoto 606–8502 Japan
Ren Shimamoto, Kyoto University Graduate School of Biostudies Kyoto 606–8502 Japan
Kunio Ido, Kyoto University Graduate School of Biostudies Kyoto 606–8502 Japan
Fumihiko Sato, Kyoto University Graduate School of Biostudies Kyoto 606–8502 Japan
Abstract Interfering RNA was used to suppress simultaneously the expression of the four genes which encode the PsbO and PsbP proteins
of Photosystem II in Arabidopsis (PsbO: At5g66570, At3g50820 and PsbP: At1g06680, At2g30790). A phenotypic series of transgenic plants was obtained that expressed
variable amounts of the PsbO proteins and undetectable amounts of the PsbP proteins. Immunological studies indicated that
the loss of PsbP expression was correlated with the loss of expression of the PsbQ, D2, and CP47 proteins, while the loss
of PsbO expression was correlated with the loss of expression of the D1 and CP43 proteins. QA− reoxidation kinetics in the absence of DCMU indicated that the slowing of electron transfer from QA− to QB was correlated with the loss of the PsbP protein. QA− reoxidation kinetics in the presence of DCMU indicated that charge recombination between QA− and donor side components of the photosystem was retarded in all of the mutants. Decreasing amounts of the PsbO protein in
the absence of the PsbP component also led to a progressive loss of variable fluorescence yield (FV/FM). During fluorescence induction, the loss of PsbP was correlated with a more rapid O to J transition and a loss of the J
to I transition. These results indicate that the losses of the PsbO and PsbP proteins differentially affect separate protein
components and different PS II functions and can do so, apparently, in the same plant.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9352-8
Authors
Xiaoping Yi, Louisiana State University Division of Biochemistry and Molecular Biology, Department of Biological Sciences Baton Rouge LA 70803 USA
Stefan R. Hargett, UVA Division of Endocrinology 1300 Jefferson Park Avenue #1215 Charlottesville VA 22908 USA
Laurie K. Frankel, Louisiana State University Division of Biochemistry and Molecular Biology, Department of Biological Sciences Baton Rouge LA 70803 USA
Terry M. Bricker, Louisiana State University Division of Biochemistry and Molecular Biology, Department of Biological Sciences Baton Rouge LA 70803 USA
Bacteriophytochromes in anoxygenic photosynthetic bacteria
Content Type Journal Article
Category Erratum
DOI 10.1007/s11120-008-9362-6
Authors
Eric Giraud, IRD, CIRAD, AGRO-M, INRA, UM2 Laboratoire des Symbioses Tropicales et Méditerranéennes TA A-82/J, Campus de Baillarguet 34398 Montpellier Cedex 5 France
André Verméglio, CEA, DSV, IBEB, Lab Bioenerget Cellulaire Saint-Paul-lez-Durance 13108 France
Abstract The Manganese Stabilizing Protein (MSP) of Photosystem II (PSII) is a so-called extrinsic subunit, which reversibly associates
with the other membrane-bound PSII subunits. The MSP is essential for maximum rates of O2 production under physiological conditions as stabilizes the catalytic [Mn4Ca] cluster, which is the site of water oxidation. The function of the MSP subunit in the PSII complex has been extensively
studied in higher plants, and the structure of non-PSII associated MSP has been studied by low-resolution biophysical techniques.
Recently, crystal structures of PSII from the thermophilic cyanobacterium Thermosynechococcus elongatus have resolved the MSP subunit in its PSII-associated state. However, neither any crystal structure is available yet for MSP
from mesophilic organisms, higher plants or algae nor has the non-PSII associated form of MSP been crystallized. This article
reviews the current understanding of the structure, dynamics, and function of MSP, with a particular focus on properties of
the MSP from T. elongatus that may be attributable to the thermophilic ecology of this organism rather than being general features of MSP.
Content Type Journal Article
Category Review
DOI 10.1007/s11120-008-9353-7
Authors
Adele K. Williamson, the Australian National University Research School of Biological Sciences Canberra 0200 Australia
Abstract This article provides a glimpse into the dawning of research on chlorophyll–protein complexes and a brief recollection of
the path that led us to the identification of the photosystem II reaction center, i.e., the polypeptides that carry the site
of primary charge separation in oxygenic photosynthesis. A preliminary version of the personal review on the latter topic
has already appeared in this journal (Satoh Photosynth Res 76:233–240, 2003).
Content Type Journal Article
Category Personal perspective
DOI 10.1007/s11120-008-9348-4
Authors
Kimiyuki Satoh, Okayama University Okayama 700-8530 Japan
Abstract β-carotene (Car) and chlorophyll (Chl) function as secondary electron donors in photosystem II (PS II) under conditions, such
as low temperature, when electron donation from the O2-evolving complex is inhibited. In prior studies of the formation and decay of Car•+ and Chl•+ species at low temperatures, cytochrome b559 (Cyt b559) was chemically oxidized prior to freezing the sample. In this study, the photochemical formation of Car•+ and Chl•+ is characterized at low temperature in O2-evolving Synechocystis PS II treated with ascorbate to reduce most of the Cyt b559. Not all of the Cyt b559 is reduced by ascorbate; the remainder of the PS II reaction centers, containing oxidized low-potential Cyt b559, give rise to Car•+ and Chl•+ species after illumination at low temperature that are characterized by near-IR spectroscopy. These data are compared to
the measurements on ferricyanide-treated O2-evolving Synechocystis PS II in which the Car•+ and Chl•+ species are generated in PS II centers containing mostly high- and intermediate-potential Cyt b559. Spectral differences observed in the ascorbate-reduced PS II samples include decreased intensity of the Chl•+ and Car•+ absorbance peaks, shifts in the Car•+ absorbance maxima, and lack of formation of a 750 nm species that is assigned to a Car neutral radical. These results suggest
that different spectral forms of Car are oxidized in PS II samples containing different redox forms of Cyt b559, which implies that different secondary electron donors are favored depending on the redox form of Cyt b559 in PS II.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9360-8
Authors
Cara A. Tracewell, Yale University Department of Chemistry P.O. Box 208107 New Haven CT 06520-8107 USA
Gary W. Brudvig, Yale University Department of Chemistry P.O. Box 208107 New Haven CT 06520-8107 USA
Abstract High-light illumination of photosynthetic organisms stimulates the production of singlet oxygen by photosystem II (PSII) and
causes photo-oxidative stress. In the PSII reaction centre, singlet oxygen is generated by the interaction of molecular oxygen
with the excited triplet state of chlorophyll (Chl). The triplet Chl is formed via charge recombination of the light-induced
charge pair. Changes in the midpoint potential of the primary electron donor P680 of the primary acceptor pheophytin or of the quinone acceptor QA, modulate the pathway of charge recombination in PSII and influence the yield of singlet oxygen formation. The involvement
of singlet oxygen in the process of photoinhibition is discussed. Singlet oxygen is efficiently quenched by β-carotene, tocopherol
or plastoquinone. If not quenched, it can trigger the up-regulation of genes, which are involved in the molecular defence
response of photosynthetic organisms against photo-oxidative stress.
Content Type Journal Article
Category Review
DOI 10.1007/s11120-008-9349-3
Authors
Anja Krieger-Liszkay, Service de Bioénergétique Biologie Structurale et Mécanisme CEA, Institut de Biologie et Technologies de Saclay, CNRS URA 2096 91191 Gif-sur-Yvette Cedex France
Christian Fufezan, Westfälische Wilhelms-Universität Münster Institut für Biochemie und Biotechnologie der Pflanzen 48143 Münster Germany
Abstract We isolated highly-purified photochemically active photosystem (PS) II reaction center (RC) complexes from the cyanobacterium
Synechocystis sp. PCC 6803 using a histidine-tag introduced to the 47 kDa chlorophyll protein, and characterized their spectroscopic properties.
Purification was carried out in a one-step procedure after isolation of PS II core complex. The RC complexes consist of five
polypeptides, the same as in spinach. The pigment contents per two molecules of pheophytin a were 5.8 ± 0.3 chlorophyll (Chl) a and 1.8 ± 0.1 β-carotene; one cytochrome b559 was found per 6.0 Chl a molecules. Overall absorption and fluorescence properties were very similar to those of spinach PS II RCs; our preparation
retains the best properties so far isolated from cyanobacteria. However, a clear band-shift of pheophytin a and β-carotene was observed. Reasons for these differences, and RC composition, are discussed on the basis of the three-dimensional
structure of complexes.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9354-6
Authors
Tatsuya Tomo, Kyoto University Graduate School of Human and Environmental Studies Yoshida Nihonmatsu-cho, Sakyo-ku Kyoto 606-8501 Japan
Seiji Akimoto, Kobe University Molecular Photoscience Research Center Kobe 657-8501 Japan
Tohru Tsuchiya, Kyoto University Graduate School of Human and Environmental Studies Yoshida Nihonmatsu-cho, Sakyo-ku Kyoto 606-8501 Japan
Michitaka Fukuya, Kobe University Graduate School of Science Kobe 657-8501 Japan
Kazunori Tanaka, Kobe University Graduate School of Science Kobe 657-8501 Japan
Mamoru Mimuro, Kyoto University Graduate School of Human and Environmental Studies Yoshida Nihonmatsu-cho, Sakyo-ku Kyoto 606-8501 Japan
Abstract Arginine257 (R257), in the de-helix that caps the QB site of the D1 protein, has been shown by mutational studies to play a key role in the sensitivity of Photosystem II (PS II)
to bicarbonate-reversible binding of the formate anion. In this article, the role of this residue has been further investigated
through D1 mutations (R257E, R257Q, and R257K) in Chlamydomonas reinhardtii. We have investigated the activity of the QB site by studying differences from wild type on the steady-state turnover of PS II, as assayed through chlorophyll (Chl) a fluorescence yield decay after flash excitation. The effects of p-benzoquinone (BQ, which oxidizes reduced QB, QB−) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU, which blocks electron flow from QA− to QB) were measured. The equilibrium constants of the two-electron gate were obtained through thermoluminescence measurements.
The thermoluminescence properties were changed in the mutants, especially when observed after pretreatment with 100 μM BQ.
A theoretical analysis of the thermoluminescence data, based mainly on the recombination pathways model of Rappaport et al.
(2005), led to the conclusion that the free-energy difference for the recombination of QB− with S2 was reduced by 20–40 mV in the three mutants (D1-R257K, D1-R257Q, and D1-R257E); this was interpreted to be due to a lowering
of the redox potential of QB/QB−. Further, since the recombination of QA− with S2 was unaffected, we suggest that no significant change in redox potential of QA/QA− occurred in these three mutants. The maximum variable Chl a fluorescence yield is lowered in the mutants, in the order R257K > R257Q > R257E, compared to wild type. Our analysis of
the binary oscillations in Chl a fluorescence following pretreatment of cells with BQ showed that turnover of the QB site was relatively unaffected in the three mutants. The mutant D1-R257E had the lowest growth rate and steady-state activity
and showed the weakest binary oscillations. We conclude that the size and the charge of the amino acid at the position D1-257
play a role in PS II function by modulating the effective redox potential of the QB/QB− pair. We discuss an indirect mechanism mediated through electrostatic and/or surface charge effects and the possibility of
more pleiotropic effects arising from decreased stability of the D1/D2 and D1/CP47 interfaces.
Content Type Journal Article
Category Regular Paper
DOI 10.1007/s11120-008-9351-9
Authors
Stuart Rose, University of Illinois at Urbana-Champaign Department of Biochemistry and Center for Biophysics and Computational Biology Urbana IL 61801 USA
Jun Minagawa, Hokkaido University Institute of Low Temperature Science Sapporo 060-0819 Japan
Manfredo Seufferheld, University of Illinois at Urbana-Champaign Department of Natural Resources and Environmental Sciences (NRES) 311 Edgar R. Madigan Lab (ERML), 1201 W. Gregory Drive Urbana IL 61801 USA
Sean Padden, University of Illinois at Urbana-Champaign Physiological and Molecular Plant Biology Program 286 Morrill Hall, 505 S. Goodwin Ave. Urbana IL 61801 USA
Bengt Svensson, University of Minnesota Department of Biochemistry, Molecular Biology and Biophysics 6-155 Jackson Hall, 321 Church St. SE Minneapolis MN 55455 USA
Derrick R. J. Kolling, Princeton University Department of Chemistry 17 Hoyt Laboratory, Washington Road Princeton NJ 08544 USA
Antony R. Crofts, University of Illinois at Urbana-Champaign Department of Biochemistry and Center for Biophysics and Computational Biology Urbana IL 61801 USA
Govindjee, University of Illinois at Urbana-Champaign Department of Biochemistry and Center for Biophysics and Computational Biology Urbana IL 61801 USA
