Abstract
The fluorescence yield for 694 nm excitation in a Photosystem I-200 particle is significantly lower than that for 665 nm excitation. This supports the previous suggestion, based on a thermodynamic analysis of absorption and emission spectra, that thermal equilibration in the 690–700 nm spectral interval is perturbed, presumably by primary photochemistry [Croce et al. (1996) Biochem 35: 8572–8579]. This equilibrium perturbation was used in the present study as a novel fit parameter in numerical simulations aimed at describing the kinetic/thermodynamic properties of exciton flow and primary photochemistry in PS I. To this end a four energy level scheme was developed which satisfactorily described all the fit parameters, including that of the equilibrium perturbation. An important characteristic which distinguished this model from other model studies is the presence of a number of chlorophyll molecules with absorption maximum near 695 nm, tightly coupled to P700. The main conclusions are: (I) about six chlorophyll molecules absorbing near 695 nm are tightly coupled to P700, in close agreement with the recent crystallographic structure for the Photosystem I core [Krauß et al. (1996); Nature Struct Biol 3: 965–973]; (II) energy transfer from the bulk pigments to the P700 core pigments is slow; (III) analysis of the most physically straightforward model indicates that the primary photochemical charge separation rate is very high (kpc ≥ 2.5 ps-1), though it is possible to simulate the equilibrium perturbation with lower kpc values assuming a large free energy decrease in the excited state of P700; (IV) the red spectral forms slow down reaction centre trapping by a 2–3 fold factor.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bittner T, Wiederrecht GP, Irrgang KD, Renger G and Wasielewski MR (1995) Femtosecond transient absorption spectroscopy on the light harvesting chlorophyll a/b protein complex of Photosystem II at room temperature and 12 K. Chem Phys 194: 311–322
Borisov AY (1995) New concept of energy migration and trapping in purple bacteria. Charge transfer-polaron model. Biochem Mol Biol Int 35: 833–840
Breton J, Martin JL, Migus A, Antonetti A and Orszag A (1996) Femtosecond spectroscopy of excitation energy transfer and initial charge separation in the reaction center of the photosynthetic bacterium Rhodopseudomonas viridis. Proc Natl Acad Sci USA 83: 5121–5125
Croce R, Zucchelli G, Garlaschi FM, Bassi R and Jennings RC (1996) Excited state equilibration in the Photosystem I-light-harvesting-I complex: P700 is almost isoenergetic with its antenna. Biochemistry 35: 8572–8579
Du M, Xie XL, Mets L and Fleming GR (1994) Direct observation of ultrafast energy-transfer processes in light harvesting complex II. J Phys Chem 98: 4736–4741
Eads DD, Castner EW, Alberte RS and Mets L (1989) Direct observation of energy transfer in a photosynthetic membrane: chlorophyll b to chlorophyll a transfer in LHC. J Phys Chem 93: 8271–8275
Fischer MR and Hoff AJ (1992) On the long-wavelength component of the light-harvesting complex of some photosynthetic bacteria. Biophys J 63: 911–916
Fromme P, Witt HT, Schubert WD, Klukas O, Saenger W and Krauß N (1996) Structure of Photosystem I at 4.5 Å resolution: A short review including evolutionary aspects. Biochim Biophys Acta 1275: 76–83
Gillbro T, Sundstrom V, Sandstrom Å, Spangfort M and Andersson B (1985) Energy transfer within the isolated light harvesting chlorophyll a/b protein of Photosystem II (LHC-II). FEBS Lett 193: 267–270
Hastings G, Durrant JR, Barber J, Porter G and Klug DR (1992) Observation of pheophytin reduction in Photosystem II reaction centers using femtosecond transient absorption spectroscopy. Biochemistry 31: 7638–7647
Hastings G, Kleinherenbrink FAM, Lin S and Blankenship RE (1994) Time-resolved fluorescence and absorption spectroscopy of Photosystem I. Biochemistry 33: 3185–3192
Hodges M and Moya I (1986) Time resolved chlorophyll fluorescence studies of photosynthetic membranes: Resolution and characterisation of four kinetic components. Biochim Biophys Acta 849: 193–202
Holzwarth AR (1986) Fluorescence lifetimes in photosynthetic systems. Photochem Photobiol 43: 707–725
Jean JM, Chan CK, Fleming GR and Owens TG (1989) Excitation transport and trapping on spectrally disordered lattices. Biophys J 56: 1203–1215
Jennings RC, Bassi R and Zucchelli G (1996) Antenna structure and energy transfer in higher plants photosystems. In: Mattay J (ed) Topics in Current Chemistry, 177: Electron Transfer II, pp 147–181. Springer-Verlag, Heidelberg/Berlin
Jia Y, Jean JM, Werst MM, Chan CK and Fleming GR (1992) Simulations of the temperature dependence of energy transfer in the PS I core antenna. Biophys J 63: 259–273
Krauß N, Schubert WD, Klukas O, Fromme P, Witt HT and Saenger W (1996) Photosystem I at 4.5 Å resolution represents the first structural model of a joint photosynthetic reaction centre and core antenna system. Nature Struct Biol 3: 965–973
Kudzmauskas S, Valkunas L and Borisov AY (1983) A theory of excitation transfer in photosynthetic units. J Theor Biol 105: 13–23
Kühlbrandt W, Wang DN and Fujiyoshi Y (1994) Atomic model of plant light-harvesting complex by electron crystallography. Nature 367: 614–621
Laible PD, Zipfel W and Owens TG (1994) Excited state dynamics in chlorophyll based antennae: The role of transfer equilibrium. Biophys J 66: 844–860
Owens TG, Webb SP, Mets L, Alberte RS and Fleming GR (1987) 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 USA 84: 1532–1536
Owens TG, Webb SP, Alberte RS, Mets L and Fleming GR (1988) Antenna structure and excitation dynamics in Photosystem I. I. Studies of detergent-isolated Photosystem I preparations using time-resolved fluorescence analysis. Biophys J 53: 733–745
Roelofs TA, Kwa SLS, van Grondelle R, Dekker JP and Holzwarth AR (1993) Primary processes and structure of the Photosystem-II reaction center. 2. Low-temperature picosecond fluorescence kinetics of a D1/D2/cytochrome b-559 reaction center complex isolated by short triton exposure. Biochim Biophys Acta 1143: 147–157
Scherer POJ, Fischer SF, Hörber JKH, Michel-Beyerle ME and Michel H (1985) On the temperature-dependence of the long wavelength fluorescence and absorption of Rhodopseudomonas viridis reaction centers. In: Michel-Beyerle ME (ed) Antennas and Reaction Centers of Photosynthetic Bacteria, pp 131–137. Springer-Verlag, Heidelberg, Berlin
Stepanov BI (1957) A universal relation between the absorption and luminescence spectra of complex molecules. Sov Phys Dokl 2: 81–84
Trinkunas G and Holzwarth AR (1994) Kinetic modeling of exciton migration in photosynthetic systems. 2. Simulations of excitation dynamics in two-dimensional photosystem core antenna/reaction center complexes. Biophys J 66: 415–429
Trinkunas G and Holzwarth AR (1996) Kinetic modeling of exciton migration in photosynthetic systems. 3. Application of genetic algorithms to simulations of excitation dynamics in three-dimentional Photosystem I core antenna/reaction center complexes. Biophys J 71: 351–364
Trissl HW (1993) Long-wavelength absorbing antenna pigments and heterogeneous absorption bands concentrate excitons and increase absorption cross section. Photosynth Res 35: 247–263
Trissl HW, Hecks B and Wulf K (1993) Invariable trapping times in Photosystem I upon excitation of minor long-wavelength absorbing pigments. Photochem Photobiol 57: 108–112
Turconi S, Weber N, Schweitzer G, Strotmann H and Holzwarth AR (1994) Energy transfer and charge separation kinetics in Photosystem I. 2. Picosecond fluorescence study of various PS I particles and light-harvesting complex isolated from higher plants. Biochim Biophys Acta 1187: 324–334
Valkunas L, van Mourik F and van Grondelle R (1992) On the rule of spectral and spatial inhomogeneity in the process of excitation energy transfer. J Photochem Photobiol B 15: 311–321
Valkunas L, Liuolia V, Dekker JP and van Grondelle R (1995) Description of energy migration and trapping in Photosystem I by a model with two distance scaling parameters. Photosynth Res 43: 149–154
van Grondelle R, Bergström H, Sundström V, van Dorssen RJ, Vos M and Hunter CN (1988) Excitation energy transfer in the light-harvesting antenna of photosynthetic purple bacteria: The role of the long-wavelength absorbing pigment B896. In: Scheer H and Schneider S (eds) Photosynthetic Light-harvesting Systems. Organisation and Function, pp 519–530. Walter de Gruyter, Berlin/New York
van Grondelle R, Dekker JP, Gillbro T and Sundstrom V (1994) Energy transfer and trapping in photosynthesis. Biochim Biophys Acta 1187: 1–65
Werst MM, Jia Y, Mets L and Fleming GR (1992) Energy transfer and trapping in the Photosystem I core antenna. A temperature study. Biophys J 61: 868–878
Wiederrecht GP, Seibert M, Govindjee and Wasielewski MR (1994) Femtosecond photodichroism studies of isolated Photosystem II reaction centers. Proc Natl Acad Sci USA 91: 8999–9003
Visser HM, Kleima FJ, van Stokkum IHM, van Grondelle R and van Amerongen H (1996) Probing the many energy-transfer processes in the photosynthetic light-harvesting complex at 77 K using energy-selective sub-picosecond transient absorption spectroscopy. Chem Phys 210: 297–312
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Jennings, R.C., Zucchelli, G., Croce, R. et al. Model studies on the excited state equilibrium perturbation due to reaction centre trapping in Photosystem I. Photosynthesis Research 52, 245–253 (1997). https://doi.org/10.1023/A:1005826924445
Issue Date:
DOI: https://doi.org/10.1023/A:1005826924445