Abstract
The energy transfer and charge separation kinetics of a photosystem I (PS I) core particle of an antenna size of 100 chlorophyll/P700 has been studied by combined fluorescence and transient absorption kinetics with picosecond resolution. This is the first combined picosecond study of transient absorption and fluorescence carried out on a PS I particle and the results are consistent with each other. The data were analyzed by both global lifetime and global target analysis procedures. In fluorescence major lifetime components were found to be 12 and 36 ps. The shorter-lived one shows a negative amplitude at long wavelengths and is attributed to an energy transfer process between pigments in the main antenna Chl pool and a small long-wavelength Chl pool emitting around 720 nm whereas the longer-lived component is assigned to the overall charge separation lifetime. The lifetimes resolved in transient absorption are 7-8 ps, 33 ps, and [unk]1 ns. The shortest-lived one is assigned to energy transfer between the same pigment pools as observed also in fluorescence kinetics, the middle component of 33 ps to the overall charge separation, and the long-lived component to the lifetime of the oxidized primary donor P700+. The transient absorption data indicate an even faster, but kinetically unresolved energy transfer component in the main Chl pool with a lifetime <3 ps. Several kinetic models were tested on both the fluorescence and the picosecond absorption data by global target analysis procedures. A model where the long-wave pigments are spatially and kinetically connected with the reaction center P700 is favored over a model where P700 is connected more closely with the main Chl pool. Our data show that the charge separation kinetics in these PS I particles is essentially trap limited. The relevance of our data with respect to other time-resolved studies on PS I core particles is discussed, in particular with respect to the nature and function of the long-wave pigments. From the transient absorption data we do not see any evidence for the occurrence of a reduced Chl primary electron acceptor, but we also can not exclude that possibility, provided that reoxidation of that acceptor should occur within a time <40 ps.
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Selected References
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- BUTLER W. L., NORRIS K. H. Lifetime of the long-wavelength chlorophyll fluorescence. Biochim Biophys Acta. 1963 Jan 15;66:72–77. doi: 10.1016/0006-3002(63)91168-5. [DOI] [PubMed] [Google Scholar]
- Campillo A. J., Shapiro S. L., Geacintov N. E., Swenberg C. E. Single-pulse picosecond determination of 735 nm fluorescence risetime in spinach chloroplasts. FEBS Lett. 1977 Nov 15;83(2):316–320. doi: 10.1016/0014-5793(77)81031-4. [DOI] [PubMed] [Google Scholar]
- Holzwarth A. R. Applications of ultrafast laser spectroscopy for the study of biological systems. Q Rev Biophys. 1989 Aug;22(3):239–326. doi: 10.1017/s0033583500002985. [DOI] [PubMed] [Google Scholar]
- Holzwarth A. R., Wendler J., Suter G. W. Studies on Chromophore Coupling in Isolated Phycobiliproteins: II. Picosecond Energy Transfer Kinetics and Time-Resolved Fluorescence Spectra of C-Phycocyanin from Synechococcus 6301 as a Function of the Aggregation State. Biophys J. 1987 Jan;51(1):1–12. doi: 10.1016/S0006-3495(87)83306-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jean J. M., Chan C. K., Fleming G. R., Owens T. G. Excitation transport and trapping on spectrally disordered lattices. Biophys J. 1989 Dec;56(6):1203–1215. doi: 10.1016/S0006-3495(89)82767-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jia Y., Jean J. M., Werst M. M., Chan C. K., Fleming G. R. Simulations of the temperature dependence of energy transfer in the PSI core antenna. Biophys J. 1992 Jul;63(1):259–273. doi: 10.1016/S0006-3495(92)81589-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kühlbrandt W., Wang D. N. Three-dimensional structure of plant light-harvesting complex determined by electron crystallography. Nature. 1991 Mar 14;350(6314):130–134. doi: 10.1038/350130a0. [DOI] [PubMed] [Google Scholar]
- Markwell J. P., Thornber J. P., Skrdla M. P. Effect of detergents on the reliability of a chemical assay for P-700. Biochim Biophys Acta. 1980 Jul 8;591(2):391–399. doi: 10.1016/0005-2728(80)90170-x. [DOI] [PubMed] [Google Scholar]
- Owens T. G., Webb S. P., Alberte R. S., Mets L., Fleming G. R. Antenna structure and excitation dynamics in photosystem I. I. Studies of detergent-isolated photosystem I preparations using time-resolved fluorescence analysis. Biophys J. 1988 May;53(5):733–745. doi: 10.1016/S0006-3495(88)83154-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Owens T. G., Webb S. P., Mets L., Alberte R. S., Fleming G. R. Antenna size dependence of fluorescence decay in the core antenna of photosystem I: estimates of charge separation and energy transfer rates. Proc Natl Acad Sci U S A. 1987 Mar;84(6):1532–1536. doi: 10.1073/pnas.84.6.1532. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Owens T. G., Webb S. P., Mets L., Alberte R. S., Fleming G. R. Antenna structure and excitation dynamics in photosystem I. II. Studies with mutants of Chlamydomonas reinhardtii lacking photosystem II. Biophys J. 1989 Jul;56(1):95–106. doi: 10.1016/S0006-3495(89)82654-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Roelofs T. A., Lee C. H., Holzwarth A. R. Global target analysis of picosecond chlorophyll fluorescence kinetics from pea chloroplasts: A new approach to the characterization of the primary processes in photosystem II alpha- and beta-units. Biophys J. 1992 May;61(5):1147–1163. doi: 10.1016/s0006-3495(92)81924-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schatz G. H., Brock H., Holzwarth A. R. Kinetic and Energetic Model for the Primary Processes in Photosystem II. Biophys J. 1988 Sep;54(3):397–405. doi: 10.1016/S0006-3495(88)82973-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schatz G. H., Brock H., Holzwarth A. R. Picosecond kinetics of fluorescence and absorbance changes in photosystem II particles excited at low photon density. Proc Natl Acad Sci U S A. 1987 Dec;84(23):8414–8418. doi: 10.1073/pnas.84.23.8414. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shiozawa J. A., Alberte R. S., Thornber J. P. The P700-chlorophyll a-protein. Isolation and some characteristics of the complex in higher plants. Arch Biochem Biophys. 1974 Nov;165(1):388–397. doi: 10.1016/0003-9861(74)90177-5. [DOI] [PubMed] [Google Scholar]
- Shuvalov V. A., Dolan E., Ke B. Spectral and kinetic evidence for two early electron acceptors in photosystem I. Proc Natl Acad Sci U S A. 1979 Feb;76(2):770–773. doi: 10.1073/pnas.76.2.770. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shuvalov V. A., Klevanik A. V., Sharkov A. V., Kryukov P. G., Ke B. Picosecond spectroscopy of photosystem I reaction centers. FEBS Lett. 1979 Nov 15;107(2):313–316. doi: 10.1016/0014-5793(79)80397-x. [DOI] [PubMed] [Google Scholar]
- Suter G. W., Holzwarth A. R. A kinetic model for the energy transfer in phycobilisomes. Biophys J. 1987 Nov;52(5):673–683. doi: 10.1016/S0006-3495(87)83262-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wendler J., Holzwarth A. R. State transitions in the green alga scenedesmus obliquus probed by time-resolved chlorophyll fluorescence spectroscopy and global data analysis. Biophys J. 1987 Nov;52(5):717–728. doi: 10.1016/S0006-3495(87)83266-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Werst M., Jia Y., Mets L., Fleming G. R. Energy transfer and trapping in the photosystem I core antenna. A temperature study. Biophys J. 1992 Apr;61(4):868–878. doi: 10.1016/S0006-3495(92)81894-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wittmershaus B. P., Berns D. S., Huang C. Picosecond time-resolved fluorescence from detergent-free photosystem I particles. Biophys J. 1987 Nov;52(5):829–836. doi: 10.1016/S0006-3495(87)83276-9. [DOI] [PMC free article] [PubMed] [Google Scholar]