1
|
Absorption Detected Magnetic Resonance of D1/D2-Complexes fromPisum sativum*. Z PHYS CHEM 2011. [DOI: 10.1524/zpch.1992.1.part_2.167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
2
|
Renger T, Holzwarth AR. Theory of Excitation Energy Transfer and Optical Spectra of Photosynthetic Systems. BIOPHYSICAL TECHNIQUES IN PHOTOSYNTHESIS 2008. [DOI: 10.1007/978-1-4020-8250-4_21] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
3
|
Yakovlev AG, Taisova AS, Fetisova ZG. Light control over the size of an antenna unit building block as an efficient strategy for light harvesting in photosynthesis. FEBS Lett 2002; 512:129-32. [PMID: 11852066 DOI: 10.1016/s0014-5793(02)02238-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
It was shown that an increase in the bacteriochlorophyll (BChl) c antenna size observed upon lowering growth light intensities led to enhancement of the hyperchromism of the BChl c Q(y) absorption band of the green photosynthetic bacterium Chloroflexus aurantiacus. With femtosecond difference absorption spectroscopy, it was shown that the amplitude of bleaching of the oligomeric BChl c Q(y) band (as compared to that for monomeric BChl a) increased with increasing BChl c content in chlorosomes. This BChl c bleaching amplitude was about doubled as the chlorosomal antenna size was about trebled. Both sets of findings clearly show that a unit BChl c aggregate in the chlorosomal antenna is variable in size and governed by the grow light intensity, thus ensuring the high efficiency of energy transfer within the BChl c antenna regardless of its size.
Collapse
Affiliation(s)
- A G Yakovlev
- A.N. Belozersky Institute of Physico-Chemical Biology, Bldg. 'A', Moscow State University, 119899, Moscow, Russia
| | | | | |
Collapse
|
4
|
Germano M, Shkuropatov AY, Permentier H, de Wijn R, Hoff AJ, Shuvalov VA, van Gorkom HJ. Pigment organization and their interactions in reaction centers of photosystem II: optical spectroscopy at 6 K of reaction centers with modified pheophytin composition. Biochemistry 2001; 40:11472-82. [PMID: 11560495 DOI: 10.1021/bi010439j] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Photosystem II reaction centers (RC) with selectively exchanged pheophytin (Pheo) molecules as described in [Germano, M., Shkuropatov, A. Ya., Permentier, H., Khatypov, R. A., Shuvalov, V. A., Hoff, A. J., and van Gorkom, H. J. (2000) Photosynth. Res. 64, 189-198] were studied by low-temperature absorption, linear and circular dichroism, and triplet-minus-singlet absorption-difference spectroscopy. The ratio of extinction coefficients epsilon(Pheo)/epsilon(Chl) for Q(Y) absorption in the RC is approximately 0.40 at 6 K and approximately 0.45 at room temperature. The presence of 2 beta-carotenes, one parallel and one perpendicular to the membrane plane, is confirmed. Absorption at 670 nm is due to the perpendicular Q(Y) transitions of the two peripheral chlorophylls (Chl) and not to either Pheo. The "core" pigments, two Pheo and four Chl absorb in the 676-685 nm range. Delocalized excited states as predicted by the "multimer model" are seen in the active branch. The inactive Pheo and the nearby Chl, however, mainly contribute localized transitions at 676 and 680 nm, respectively, although large CD changes indicate that exciton interactions are present on both branches. Replacement of the active Pheo prevents triplet formation, causes an LD increase at 676 and 681 nm, a blue-shift of 680 nm absorbance, and a bleach of the 685 nm exciton band. The triplet state is mainly localized on the Chl corresponding to B(A) in purple bacteria. Both Pheo Q(Y) transitions are oriented out of the membrane plane. Their Q(X) transitions are parallel to that plane, so that the Pheos in PSII are structurally similar to their homologues in purple bacteria.
Collapse
Affiliation(s)
- M Germano
- Biophysics Department, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
5
|
Prokhorenko VI, Holzwarth AR. Primary Processes and Structure of the Photosystem II Reaction Center: A Photon Echo Study,. J Phys Chem B 2000. [DOI: 10.1021/jp002323n] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Valentin I. Prokhorenko
- Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34-36, D-45413 Mülheim a.d. Ruhr, Germany
| | - Alfred R. Holzwarth
- Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34-36, D-45413 Mülheim a.d. Ruhr, Germany
| |
Collapse
|
6
|
Savikhin S, Xu W, Chitnis PR, Struve WS. Ultrafast primary processes in PS I from Synechocystis sp. PCC 6803: roles of P700 and A(0). Biophys J 2000; 79:1573-86. [PMID: 10969018 PMCID: PMC1301050 DOI: 10.1016/s0006-3495(00)76408-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The excitation transport and trapping kinetics of core antenna-reaction center complexes from photosystem I of wild-type Synechocystis sp. PCC 6803 were investigated under annihilation-free conditions in complexes with open and closed reaction centers. For closed reaction centers, the long-component decay-associated spectrum (DAS) from global analysis of absorption difference spectra excited at 660 nm is essentially flat (maximum amplitude <10(-5) absorbance units). For open reaction centers, the long-time spectrum (which exhibits photobleaching maxima at approximately 680 and 700 nm, and an absorbance feature near 690 nm) resembles one previously attributed to (P700(+) - P700). For photosystem I complexes excited at 660 nm with open reaction centers, the equilibration between the bulk antenna and far-red chlorophylls absorbing at wavelengths >700 nm is well described by a single DAS component with lifetime 2.3 ps. For closed reaction centers, two DAS components (2.0 and 6.5 ps) are required to fit the kinetics. The overall trapping time at P700 ( approximately 24 ps) is very nearly the same in either case. Our results support a scenario in which the time constant for the P700 --> A(0) electron transfer is 9-10 ps, whereas the kinetics of the subsequent A(0) --> A(1) electron transfer are still unknown.
Collapse
Affiliation(s)
- S Savikhin
- Ames Laboratory, U. S. Department of Energy, Ames, Iowa 50011, USA
| | | | | | | |
Collapse
|
7
|
Vavilin DV, Ermakova-Gerdes SY, Keilty AT, Vermaas WF. Tryptophan at position 181 of the D2 protein of photosystem II confers quenching of variable fluorescence of chlorophyll: implications for the mechanism of energy-dependent quenching. Biochemistry 1999; 38:14690-6. [PMID: 10545195 DOI: 10.1021/bi9915622] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The lumenal CD loop region of the D2 protein of photosystem II contains residues that interact with a reaction center chlorophyll and the redox-active Tyr(D). Using combinatorial mutagenesis, photoautotrophic mutants of Synechocystis sp. PCC 6803 have been generated with multiple amino acid changes in this region. The CD loop mutations were transferred into a photosystem I-less Synechocystis strain to facilitate characterization of photosystem II properties in the mutants. Most of the combinatorial photosystem I-less mutants obtained had a high yield of variable fluorescence, F(V). However, in three mutants, which shared a replacement of Phe181 by Trp, the F(V) yield was dramatically reduced although a high rate of oxygen evolution was maintained. A site-directed F181W D2 mutant shared similar properties. Picosecond time-resolved fluorescence measurements revealed that in the combinatorial F181W mutants the fluorescence lifetimes in closed and open photosystem II centers were essentially identical and were similar to the fluorescence lifetime in open centers of the control strain. These results are explained by quenching of variable fluorescence in the mutants by charge separation between Trp181 and excited reaction center chlorophyll. This reaction competes efficiently with fluorescence and nonradiative decay in closed photosystem II centers, where the lifetime of the excitation in the chlorophyll antenna is long. Thermodynamic considerations favor the formation of oxidized tryptophan and reduced chlorophyll in the quenching reaction, presumably followed by charge recombination. A possible role of tryptophan-chlorophyll charge separation in the mechanism of energy-dependent quenching of excitations in photosynthesis is discussed.
Collapse
Affiliation(s)
- D V Vavilin
- Department of Plant Biology and Center for the Study of Early Events in Photosynthesis, Arizona State University, Box 871601, Tempe, Arizona 85287-1601, USA.
| | | | | | | |
Collapse
|
8
|
Konermann L, Gatzen G, Holzwarth AR. Primary Processes and Structure of the Photosystem II Reaction Center. 5. Modeling of the Fluorescence Kinetics of the D1−D2−cyt-b559 Complex at 77 K. J Phys Chem B 1997. [DOI: 10.1021/jp9606671] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lars Konermann
- Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34-36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Guido Gatzen
- Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34-36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Alfred R. Holzwarth
- Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34-36, D-45470 Mülheim a.d. Ruhr, Germany
| |
Collapse
|
9
|
Wavelength and intensity dependent primary photochemistry of isolated Photosystem II reaction centers at 5°C. Chem Phys 1996. [DOI: 10.1016/0301-0104(96)00185-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
10
|
Groot ML, Dekker JP, van Grondelle R, den Hartog FTH, Völker S. Energy Transfer and Trapping in Isolated Photosystem II Reaction Centers of Green Plants at Low Temperature. A Study by Spectral Hole Burning. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp960326n] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. L. Groot
- Department of Biophysics, Faculty of Physics and Astronomy, Free University, 1081 HV Amsterdam, The Netherlands, and Center for the Study of Excited States of Molecules, Huygens and Gorlaeus Laboratories, University of Leiden, 2300 RA Leiden, The Netherlands
| | - J. P. Dekker
- Department of Biophysics, Faculty of Physics and Astronomy, Free University, 1081 HV Amsterdam, The Netherlands, and Center for the Study of Excited States of Molecules, Huygens and Gorlaeus Laboratories, University of Leiden, 2300 RA Leiden, The Netherlands
| | - R. van Grondelle
- Department of Biophysics, Faculty of Physics and Astronomy, Free University, 1081 HV Amsterdam, The Netherlands, and Center for the Study of Excited States of Molecules, Huygens and Gorlaeus Laboratories, University of Leiden, 2300 RA Leiden, The Netherlands
| | - F. T. H. den Hartog
- Department of Biophysics, Faculty of Physics and Astronomy, Free University, 1081 HV Amsterdam, The Netherlands, and Center for the Study of Excited States of Molecules, Huygens and Gorlaeus Laboratories, University of Leiden, 2300 RA Leiden, The Netherlands
| | - S. Völker
- Department of Biophysics, Faculty of Physics and Astronomy, Free University, 1081 HV Amsterdam, The Netherlands, and Center for the Study of Excited States of Molecules, Huygens and Gorlaeus Laboratories, University of Leiden, 2300 RA Leiden, The Netherlands
| |
Collapse
|
11
|
Müller MG, Hucke M, Reus M, Holzwarth AR. Primary Processes and Structure of the Photosystem II Reaction Center. 4. Low-Intensity Femtosecond Transient Absorption Spectra of D1-D2-cyt-b559 Reaction Centers,. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp953714i] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marc G. Müller
- Max-Planck-Institut für Strahlenchemie, Stiftstr. 34−36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Mathias Hucke
- Max-Planck-Institut für Strahlenchemie, Stiftstr. 34−36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Michael Reus
- Max-Planck-Institut für Strahlenchemie, Stiftstr. 34−36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Alfred R. Holzwarth
- Max-Planck-Institut für Strahlenchemie, Stiftstr. 34−36, D-45470 Mülheim a.d. Ruhr, Germany
| |
Collapse
|
12
|
Müller MG, Hucke M, Reus M, Holzwarth AR. Annihilation Processes in the Isolated D1-D2-cyt-b559 Reaction Center Complex of Photosystem II. An Intensity-Dependence Study of Femtosecond Transient Absorption,. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp953715a] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. G. Müller
- Max-Planck-Institut für Strahlenchemie, Stiftstr. 34-36; D-45470 Mülheim a.d. Ruhr, Germany
| | - M. Hucke
- Max-Planck-Institut für Strahlenchemie, Stiftstr. 34-36; D-45470 Mülheim a.d. Ruhr, Germany
| | - M. Reus
- Max-Planck-Institut für Strahlenchemie, Stiftstr. 34-36; D-45470 Mülheim a.d. Ruhr, Germany
| | - A. R. Holzwarth
- Max-Planck-Institut für Strahlenchemie, Stiftstr. 34-36; D-45470 Mülheim a.d. Ruhr, Germany
| |
Collapse
|
13
|
Greenfield SR, Wasielewski MR. Excitation energy transfer and charge separation in the isolated Photosystem II reaction center. PHOTOSYNTHESIS RESEARCH 1996; 48:83-97. [PMID: 24271289 DOI: 10.1007/bf00040999] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/1996] [Accepted: 01/22/1996] [Indexed: 06/02/2023]
Abstract
The nature of excitation energy transfer and charge separation in isolated Photosystem II reaction centers is an area of considerable interest and controversy. Excitation energy transfer from accessory chlorophyll a to the primary electron donor P680 takes place in tens of picoseconds, although there is some evidence that thermal equilibration of the excitation between P680 and a subset of the accessory chlorophyll a occurs on a 100-fs timescale. The intrinsic rate for charge separation at low temperature is accepted to be ca. (2 ps)(-1), and is based on several measurements using different experimental techniques. This rate is in good agreement with estimates based on larger sized particles, and is similar to the rate observed with bacterial reaction centers. However, near room temperature there is considerable disagreement as to the observed rate for charge separation, with several experiments pointing to a ca. (3 ps)(-1) rate, and others to a ca. (20 ps)(-1) rate. These processes and the experiments used to measure them will be reviewed.
Collapse
Affiliation(s)
- S R Greenfield
- Argonne National Laboratory, Chemistry Division, 60439-4831, Argonne, IL, USA
| | | |
Collapse
|
14
|
Gatzen G, Müller MG, Griebenow K, Holzwarth AR. Primary Processes and Structure of the Photosystem II Reaction Center. 3. Kinetic Analysis of Picosecond Energy Transfer and Charge Separation Processes in the D1−D2−cyt-b559 Complex Measured by Time-Resolved Fluorescence. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9530865] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Guido Gatzen
- Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34−36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Marc G. Müller
- Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34−36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Kai Griebenow
- Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34−36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Alfred R. Holzwarth
- Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34−36, D-45470 Mülheim a.d. Ruhr, Germany
| |
Collapse
|
15
|
Donovan B, Walker LA, Yocum CF, Sension RJ. Transient Absorption Studies of the Primary Charge Separation in Photosystem II. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp951984v] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Brent Donovan
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | - Larry A. Walker
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | - Charles F. Yocum
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | | |
Collapse
|
16
|
Klug DR, Rech T, Melissa Joseph D, Barber J, Durrant JR, Porter G. Primary processes in isolated Photosystem II reaction centres probed by magic angle transient absorption spectroscopy. Chem Phys 1995. [DOI: 10.1016/0301-0104(95)00037-o] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
17
|
van Amerongen H, van Grondelle R. Transient absorption spectroscopy in study of processes and dynamics in biology. Methods Enzymol 1995; 246:201-26. [PMID: 7752925 DOI: 10.1016/0076-6879(95)46011-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- H van Amerongen
- Department of Physics and Astronomy, Free University of Amsterdam, The Netherlands
| | | |
Collapse
|
18
|
|
19
|
Energy transfer, charge separation and pigment arrangement in the reaction center of Photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1994. [DOI: 10.1016/0005-2728(94)90229-1] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
20
|
Yruela I, van Kan PJ, Müller MG, Holzwarth AR. Characterization of a D1-D2-cyt b-559 complex containing 4 chlorophyll a/2 pheophytin a isolated with the use of MgSO4. FEBS Lett 1994; 339:25-30. [PMID: 8313975 DOI: 10.1016/0014-5793(94)80377-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A D1-D2-cyt b-559 complex containing 4 chlorophyll alpha, 1 beta-carotene and 1 cytochrome b-559 per 2 pheophytin a has been isolated from spinach with 30% yield using a Q-Sepharose Fast-Flow anion-exchange column equilibrated with 0.1% Triton X-100, 10 mM MgSO4 and 50 mM Tris-HCl (pH 7.2). The preparation was then stabilized with 0.1% dodecyl-beta-D-maltoside. This method gave a yield 10 times higher than that using a Fractogel TSK-DEAE 650(S) column equilibrated with 0.1% Triton X-100, 30 mM NaCl and 50 mM Tris-HCl (pH 7.2). The PS II RC complex was characterized using absorption and fluorescence spectroscopy at 277 and 77 K. A selective reversible bleaching under reducing conditions with maximum at 682 nm, associated with pheophytin a reduction, and light-induced absorption differences with a lifetime of 1.0 ms, ascribed to the triplet state of P680 were measured and indicated that the isolated D1-D2-cyt b-559 complex is active in charge separation. The results are compared with the data obtained for a PS II RC preparation containing 6 chlorophyll alpha, 2 beta-carotene and 1 cyt b-559 per 2 pheophytin a.
Collapse
Affiliation(s)
- I Yruela
- Max-Planck Institut für Strahlenchemie, Mülheim an der Ruhr, Germany
| | | | | | | |
Collapse
|
21
|
Evans E, Brown RG. New trends in photobiology. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1994. [DOI: 10.1016/1011-1344(93)06925-s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
22
|
Pico- and nanosecond fluorescence kinetics of Photosystem II reaction centre and its complex with CP47 antenna. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1994. [DOI: 10.1016/0005-2728(94)90152-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
23
|
Durrant JR, Hastings G, Joseph DM, Barber J, Porter G, Klug DR. Rate of oxidation of P680 in isolated photosystem 2 reaction centers monitored by loss of chlorophyll stimulated emission. Biochemistry 1993; 32:8259-67. [PMID: 8347624 DOI: 10.1021/bi00083a029] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We have continued our studies of the primary photochemistry of isolated photosystem 2 reaction centers using femtosecond transient absorption spectroscopy. Experiments were performed over a wide range of excitation and probe wavelengths, using several data collection time scales. This has enabled us to resolve five different lifetimes ranging between 100 fs and 200 ps plus a nanosecond component. We demonstrate here and elsewhere [e.g., Durrant, J.R., Hastings, G., Joseph, D. M., Barber, J., Porter, G., & Klug, D. R. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 11632-11636] that the kinetic spectra associated with all but two of these lifetimes are clearly distinguishable. We have previously reported that a 21-ps lifetime is associated with pheophytin reduction [Hastings, G., Durrant, J. R., Hong, Q., Barber, J., Porter, G., & Klug, D. R. (1992) Biochemistry 31, 7638-7647]. In this paper, we show that it is possible to spectrally and temporally resolve stimulated emission from PS2 reaction centers with great accuracy and that this stimulated emission is largely unaffected by those kinetic components which are faster than 21 ps. The observation of a distinct stimulated emission band allows us to distinguish charge-separated states from chlorin singlet states. In this way, we are able to show that the proportion of charge-separated states prior to the 21-ps component is between 0% and 25%. We also show that the shape of the spectrum which we obtain for the state P680+Ph- is essentially invariant between 100 ps and 9 ns, and is the same as that previously reported for P680+Ph- by other researchers.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J R Durrant
- Department of Biology, Imperial College, London, U.K
| | | | | | | | | | | |
Collapse
|
24
|
Redox potentials of cytochrome b-559 in the D1/D2/cytochrome b-559 reaction centre of Photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90149-a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
25
|
Angerhofer A, Bernlochner D, Robert B. Absorption Detected Magnetic Resonance of D1/D2-Complexes from Pisum sativum*. ACTA ACUST UNITED AC 1993. [DOI: 10.1524/zpch.1993.182.part_1_2.167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- A. Angerhofer
- 3. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - D. Bernlochner
- 3. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - B. Robert
- Départment de Biologie, CEN-Saclay, F-91191 Gif-Sur-Yvette, France
| |
Collapse
|
26
|
Liu B, Napiwotzki A, Eckert HJ, Eichler H, Renger G. Studies on the recombination kinetics of the radical pair P680+Pheo− in isolated PS II core complexes from spinach. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90094-v] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
27
|
van der Vos R, van Leeuwen PJ, Braun P, Hoff AJ. Analysis of the optical absorbance spectra of D1-D2-cytochrome b-559 complexes by absorbance-detected magnetic resonance. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1992. [DOI: 10.1016/0005-2728(92)90008-p] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
28
|
|
29
|
Hastings G, Durrant JR, Barber J, Porter G, Klug DR. Observation of pheophytin reduction in photosystem two reaction centers using femtosecond transient absorption spectroscopy. Biochemistry 1992; 31:7638-47. [PMID: 1510949 DOI: 10.1021/bi00148a027] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Photosystem two reaction centers have been studied using a sensitive femtosecond transient absorption spectrometer. Measurements were performed at 295 K using different excitation wavelengths and excitation intensities which are shown to avoid multiphoton absorption by the reaction centers. Analyses of results collected over a range of time scales and probe wavelengths allowed the resolution of two exponential components in addition to those previously reported [Durrant, J. R., Hastings, G., Hong, Q., Barber, J., Porter, G., & Klug, D. R. (1992) Chem. Phys. Lett. 188, 54-60], plus the long-lived radical pair itself. A 21-ps component was observed. The process(es) responsible for this component was (were) found to produce bleaching of a pheophytin ground-state absorption band at 545 nm and the simultaneous appearance of a pheophytin anion absorption band at 460 nm resulting in a transient spectrum which was that of the radical pair P680+Ph-. This component is assigned to the production of reduced pheophytin. A lower limit of 60% of the final pheophytin reduction was found to occur at this rate. Despite subtle differences in transient spectra, the lifetime and yield of this pheophytin reduction are essentially independent of excitation wavelength within the signal to noise limitations of these experiments. A long-lived species was also observed. This species is produced by those processes which result in the 21-ps component, and it has a spectrum which is found to be independent of excitation wavelength. This spectrum is characteristic of the primary radical pair state P680+Ph-. In addition, a 200-ps component was found which is tentatively assigned to a slow energy-transfer/trapping process. This component was absent if P680 was excited directly and is therefore not integral to primary radical pair formation. Overall, it is concluded that the rate of pheophytin reduction is limited to (21 ps)-1, even when P680 is directly excited.
Collapse
Affiliation(s)
- G Hastings
- Department of Biology, Imperial College, London, United Kingdom
| | | | | | | | | |
Collapse
|
30
|
Maciy K, Renger G, Haag E, Voigt J. Light-induced degradation of PS II reaction centres analyzed by measurements of steady-state fluorescence spectra in D1/D2/cytochrome b-559 preparations from spinach. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1992. [DOI: 10.1016/0005-2728(92)90067-c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|