Abstract：
:The temperature dependence of the partial reactions leading to turn-over of the UQH2:cyt c 2 oxidoreductase of Rhodobacter sphaeroides have been studied. The redox properties of the cytochrome components show a weak temperature dependence over the range 280-330 K, with coefficients of about 1 m V per degree; our results suggest that the other components show similar dependencies, so that no significant change in the gradient of standard free-energy between components occurs over this temperature range. The rates of the reactions of the high potential chain (the Rieske iron sulfur center, cytochromes c 1 and c 2, reaction center primary donor) show a weak temperature dependence, indicating an activation energy < 8 kJ per mole for electron transfer in this chain. The oxidation of ubiquinol at the Qz-site of the complex showed a strong temperature dependence, with an activation energy of about 32 kJ mole(-1). The electron transfer from cytochrome b-566 to cytochrome b-561 was not rate determining at any temperature, and did not contribute to the energy barrier. The activation energy of 32 kJ mole(-1) for quinol oxidation was the same for all states of the quinone pool (fully oxidized, partially reduced, or fully reduced before the flash). We suggest that the activation barrier is in the reaction by which ubiquinol at the catalytic site is oxidized to semiquinone. The most economical scheme for this reaction would have the semiquinone intermediate at the energy level indicated by the activation barrier. We discuss the plausibility of this simple model, and the values for rate constants, stability constant, the redox potentials of the intermediate couples, and the binding constant for the semiquinone, which are pertinent to the mechanism of the ubiquinol oxidizing site.
journal_name
Photosynth Resjournal_title
Photosynthesis researchauthors
Crofts AR,Wang Zdoi
10.1007/BF00114768subject
Has Abstractpub_date
1989-01-01 00:00:00pages
69-87issue
1eissn
0166-8595issn
1573-5079journal_volume
22pub_type
杂志文章abstract：:The chlorina-f2 mutant of barley (Hordeum vulgare L.) contains no chlorophyll b in its light-harvesting antenna, whereas the chlorina-103 mutant contains approximately 10% of the chlorophyll b found in wild-type. The absolute chlorophyll antenna size for Photosystem-II in wild-type, chlorina-103 and chlorina-f2 mutant...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00146413
更新日期：1993-11-01 00:00:00
abstract：:Photosystem II (PSII) catalyzes the oxidation of water to O2 at the manganese-containing, oxygen-evolving complex (OEC). Photoexcitation of PSII results in the oxidation of the OEC; four sequential oxidation reactions are required for the generation and release of molecular oxygen. Therefore, with flash illumination, ...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-007-9147-3
更新日期：2007-06-01 00:00:00
abstract：:The dependence on temperature of tryptophan fluorescence lifetime in trimeric photosystem I (PSI) complexes from cyanobacteria Synechocystis sp. PCC 6803 during the heating of pre-frozen to - 180 °C in the dark or in the light-activated preparations has been studied. Fluorescence lifetime in samples frozen in the ligh...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-018-0595-8
更新日期：2019-03-01 00:00:00
abstract：:Solubilisation of thylakoid membranes from young leaves of Pisum sativum in the presence of Triton X-100 resulted in an almost complete loss of quenching of light-harvesting chlorophyll-protein (LHCP) fluorescence, as measured at 77°K. There were concomitant changes in the kinetics of light-saturation curves of electr...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00037130
更新日期：1986-01-01 00:00:00
abstract：: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 inf...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-011-9671-z
更新日期：2012-03-01 00:00:00
abstract：:A chloroplast preparation was extracted from squash (Cucurbita pepo (L.) var. Senator). Enrichment of intact chloroplasts was achieved by continuous free-flow electrophoresis. The addition of monoterpenes, detergent and free fatty acids changed the elecrophoretic separation pattern characteristically. Monoterpene-depe...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00054124
更新日期：1991-06-01 00:00:00
abstract：:Roderick K. Clayton passed away on October 23, 2011, at the age of 89, shortly after the plan for this dedicatory issue of Photosynthesis Research had been hatched. I had just written a lengthy letter to him to re-establish contact after a hiatus of 2 or 3 years, and to suggest that I visit him to talk about his life....
journal_title：Photosynthesis research
pub_type： 传,历史文章,杂志文章
doi：10.1007/s11120-013-9948-5
更新日期：2014-05-01 00:00:00
abstract：:Photosynthesis powers our planet and is a source of inspiration for developing artificial constructs mimicking many aspects of the natural energy transducing process. In the complex machinery of photosystem II (PSII), the redox activity of the tyrosine Z (Tyrz) hydrogen-bonded to histidine 190 (His190) is essential fo...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-020-00815-x
更新日期：2021-01-11 00:00:00
abstract：:We have used antibodies generated against synthetic peptides to determine the topology of the 43 kD chlorophyll a binding protein (CP 43) of Photosystem II. Based on the pattern of proteolytic fragments detected (on western blots) by peptide specific antibodies, a six transmembrane span topological model, with the ami...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00019041
更新日期：1994-04-01 00:00:00
abstract：:We present here the life and work of Shmuel Malkin (1934-2017), an accomplished scientist and a gifted musician who touched the lives of many around the world. His early scientific work addressed the dynamics of light harvesting and electron transport in photosynthesis. Later, he used photoacoustic and photothermal me...
journal_title：Photosynthesis research
pub_type： 传,历史文章,杂志文章
doi：10.1007/s11120-018-0478-z
更新日期：2018-07-01 00:00:00
abstract：:Illumination of the dark-incubated cells of Synechocystis PCC6803 caused recovery of both respiratory activity of oxygen uptake and PS I-cyclic electron flow, which was monitored by the dark reduction of P700(+) in the presence of DCMU after a 50 ms pulse light (MT) under background far-red light, but the effects were...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1023/A:1017946524199
更新日期：2001-01-01 00:00:00
abstract：:The possible origins of the different fluorescence decay components in green plants are discussed in terms of a random walk and Butler's bipartite model. The interaction of the excitations with the photosystem II reaction centers and, specifically, the regeneration of theses excitations by charge recombination within ...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00118288
更新日期：1986-01-01 00:00:00
abstract：:Oxygenic photosynthesis is driven by two multi-subunit membrane protein complexes, Photosystem I and Photosystem II. In plants and green algae, both complexes are composed of two moieties: a reaction center (RC), where light-induced charge translocation occurs, and a peripheral antenna that absorbs light and funnels i...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1023/B:PRES.0000036881.23512.42
更新日期：2004-01-01 00:00:00
abstract：:We evaluate low-temperature (low-T) emission spectra of photosystem II core complexes (PSII-cc) previously reported in the literature, which are compared with emission spectra of PSII-cc obtained in this work from spinach and for dissolved PSII crystals from Thermosynechococcus (T.) elongatus. This new spectral datase...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-015-0128-7
更新日期：2015-06-01 00:00:00
abstract：:This contribution gives a brief survey of the short history since the discovery of the aerobic phototrophic bacteria to focus on a general evolutionary scenario. Most of the citations are of reviews that have covered the earlier literature and to which the reader is directed at appropriate places in the following text...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1023/A:1020493518379
更新日期：2002-01-01 00:00:00
abstract：:Photoinhibition of Photosystem II (PSII) in lincomycin-treated leaves begins as a first-order reaction, but fluorescence measurements have suggested that after prolonged illumination, the number of active PSII centres stabilizes to 15-20% of control. The stabilization has been interpreted to indicate that photoinhibit...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-009-9496-1
更新日期：2010-01-01 00:00:00
abstract：:The localization of isoprenoid lipids in chloroplasts, the accumulation of particular isoprenoids under high irradiance conditions, and channelling of photosynthetically fixed carbon into plastidic thylakoid isoprenoids, volatile isoprenoids, and cytosolic sterols are reviewed. During leaf and chloroplast development ...
journal_title：Photosynthesis research
pub_type： 杂志文章,评审
doi：10.1007/s11120-007-9204-y
更新日期：2007-05-01 00:00:00
abstract：:Although it has been believed that wild-type plants are capable of protecting photosystem I (PSI) under high light, our previous study indicates that PSI is sensitive to high light in the shade-established tree species Psychotria rubra. However, the underlying physiological mechanisms are unclear. In this study, we ex...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-016-0275-5
更新日期：2016-07-01 00:00:00
abstract：:Flash-induced absorbance measurements at 830 nm on both nanosecond and microsecond timescales have been used to characterise the effect of ultraviolet light on Photosystem II core particles. A combination of UV-A and UV-B, closely simulating the spectrum of sunlight below 350 nm, was found to have a primary effect on ...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00029424
更新日期：1996-07-01 00:00:00
abstract：:Oxygen evolving photosystem II particles were exposed to 100 and 250 W m(-2) white light at 20°C under aerobic, anaerobic and strongly reducing (presence of dithionite) conditions. Three types of photoinactivation processes with different kinetics could be distinguished: (1) The fast process which occurs under strongl...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00030061
更新日期：1990-01-01 00:00:00
abstract：:Cyanobacteria, algae, and plants produce dioxygen from water. Driven and clocked by light quanta, the catalytic Mn(4)Ca Tyrosine centre accumulates four oxidizing equivalents before it abstracts four electrons from water and liberates dioxygen and protons. Intermediates of this reaction cascade are short-lived (<100 m...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-008-9321-2
更新日期：2008-10-01 00:00:00
abstract：:The pigment composition of the light-harvesting complexes of Photosystem II (LHC II) has been determined for lettuce (Lactuca sativa). In common with other members of the composite, the photosynthetic tissues of this species may contain large amounts of the carotenoid lactucaxanthin (ε, ε-carotene-3,3'-diol) in additi...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00029940
更新日期：1995-03-01 00:00:00
abstract：:Phosphoenolpyruvate carboxylase from leaves of the C4 plant Setaria verticillata (L.) Beauv. is activated by light; day levels of activity are reached after 30 minutes of illumination. Photoactivation is prevented by inhibitors of photosynthetic electron flow or of photophosphorylation and by D,L-glyceraldehyde, which...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00028842
更新日期：1988-06-01 00:00:00
abstract：:Inorganic phosphate participates in many fundamental processes within the plant cell. Its broad influence on plant metabolism is related to such key operations as metabolite transport, enzyme regulation and carbohydrate metabolism in general. This review discusses these topics with special emphasis on the role assigne...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00016551
更新日期：1993-03-01 00:00:00
abstract：:Photoacclimation by strains of Haslea "blue" diatom species H. ostrearia and H. silbo sp. nov. ined. was investigated with rapid light curves and induction-recovery curves using fast repetition rate fluorescence. Cultures were grown to exponential phase under 50 µmol m-2 s-1 photosynthetic available radiation (PAR) an...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-018-0508-x
更新日期：2018-09-01 00:00:00
abstract：:Since 1986, non-uniform photosynthesis over the leaf area that may be attributed to patchy stomatal closure, has been an important issue in stress physiology of photosynthesis. In this review, I first outline the gaseous environment within the intercellular spaces, because this is the most fundamental background of th...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00035537
更新日期：1992-03-01 00:00:00
abstract：:We pay tribute to the life and work of Margareta Ryberg (1946-2012). She was an expert on the different forms of protochlorophyll(ide), their protein partners, and their transformations in angiosperms; on the structural aspects, and the nature of prolamellar bodies, as well as on the localization of light-dependent NA...
journal_title：Photosynthesis research
pub_type： 传,历史文章,杂志文章
doi：10.1007/s11120-012-9752-7
更新日期：2012-09-01 00:00:00
abstract：:Upon high light excitation in photosynthetic bacteria, various triplet states of pigments can accumulate leading to harmful effects. Here, the generation and lifetime of flash-induced carotenoid triplets (3Car) have been studied by observation of the quenching of bacteriochlorophyll (BChl) fluorescence in different st...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/s11120-017-0434-3
更新日期：2018-04-01 00:00:00
abstract：:Using 77 K chlorophyll a (Chl a) fluorescence spectra in vivo, the development was studied of Photosystems II (PS II) and I (PS I) during greening of barley under intermittent light followed by continuous light at low (LI, 50 mumol m(-2) s(-1)) and high (HI, 1000 mumol m(-2) s(-1)) irradiances. The greening at HI inte...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1023/A:1020943107318
更新日期：2002-01-01 00:00:00
abstract：:The effect of temperatures between 15 and 50°C on the light utilization efficiency of leaf net photosynthesis was studied in two C4 grasses and two C3 legumes. In the legumes, light utilization efficiency (μ mol of CO2 fixed per μ Einstein of incident photosynthetic quantum flux) declined linearly with temperature bet...
journal_title：Photosynthesis research
pub_type： 杂志文章
doi：10.1007/BF00034267
更新日期：1981-12-01 00:00:00
