Singlet–Singlet Annihilation Kinetics in Aggregates and Trimers of LHCII

Barzda, Virginijus; Gulbinas, Vidmantas; Kananavičius, Robertas; Cervinskas, V.; Amerongen, Herbert van; Grondelle, Rienk van; Valkūnas, Leonas

doi:10.1016/s0006-3495(01)76210-8

Cited by 143 publications

(170 citation statements)

References 76 publications

Supporting

Mentioning

146

Contrasting

Order By: Relevance

“…This DAS describes energy transfer, which is observed to be rather conservative in the BBY membranes, with loss of emission at 675 nm, a zero-crossing at 682 nm and a gain at 687 nm. This DAS is interpreted as energy transfer from LHCII to the PSII core complex (Andrizhiyevskaya et al 2005), where the transfer timescale is in agreement with the 32 ps migration time of excitations between LHCII trimers which was estimated at room temperature (Barzda et al 2001;Van Amerongen and Van Grondelle 2001). The non-conservativity is explained by trapping taking place on a similar timescale in PSII.…”

Section: K Time-resolved Fluorescencesupporting

confidence: 77%

“…The DAS of the unstacked membranes, extends to the blue with respect to the native DAS, with its maximum at 680 nm, but moreover it shows a small rise of fluorescence around 730 nm. Energy transfer from LHCII trimers to other complexes is expected to occur on this time-range (Barzda et al 2001;Van Amerongen and Van Grondelle 2001) as well. Thus, the spectrum and amplitude of the 25 ps energy transfer component in the unstacked membranes with the positive feature at 675-680 nm and the negative feature above 720 nm and the absence of these characteristics in the native membranes can be explained by energy transfer from LHCII to PSI in presumably LHCII-LHCI-PSI complexes.…”

Section: Room Temperature Time-resolved Fluorescencementioning

confidence: 99%

See 1 more Smart Citation

Excitation energy transfer in native and unstacked thylakoid membranes studied by low temperature and ultrafast fluorescence spectroscopy

et al. 2007

Self Cite

View full text Add to dashboard Cite

In this work, the transfer of excitation energy was studied in native and cation-depletion induced, unstacked thylakoid membranes of spinach by steady-state and time-resolved fluorescence spectroscopy. Fluorescence emission spectra at 5 K show an increase in photosystem I (PSI) emission upon unstacking, which suggests an increase of its antenna size. Fluorescence excitation measurements at 77 K indicate that the increase of PSI emission upon unstacking is caused both by a direct spillover from the photosystem II (PSII) core antenna and by a functional association of light-harvesting complex II (LHCII) to PSI, which is most likely caused by the formation of LHCII-LHCI-PSI supercomplexes. Time-resolved fluorescence measurements, both at room temperature and at 77 K, reveal differences in the fluorescence decay kinetics of stacked and unstacked membranes. Energy transfer between LHCII and PSI is observed to take place within 25 ps at room temperature and within 38 ps at 77 K, consistent with the formation of LHCII-LHCI-PSI supercomplexes. At the 150-160 ps timescale, both energy transfer from LHCII to PSI as well as spillover from the core antenna of PSII to PSI is shown to occur at 77 K. At room temperature the spillover and energy transfer to PSI is less clear at the 150 ps timescale, because these processes compete with charge separation in the PSII reaction center, which also takes place at a timescale of about 150 ps.

show abstract

Section: K Time-resolved Fluorescencesupporting

confidence: 77%

Section: Room Temperature Time-resolved Fluorescencementioning

confidence: 99%

Excitation energy transfer in native and unstacked thylakoid membranes studied by low temperature and ultrafast fluorescence spectroscopy

et al. 2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…In some studies with LHCII, this component has been described as an artifact that is either due to aggregation of the complexes or due to high excitation powers. 50 It has also been found in the case of monomeric systems and actually shows up more pronounced in studies with reconstituted systems. 47,48,51 However, as stated above, in the case of LHCI proteins, a similar component was found in both native and reconstituted systems.…”

Section: Discussionmentioning

confidence: 76%

Excitation Decay Pathways of Lhca Proteins: A Time-Resolved Fluorescence Study

et al. 2005

View full text Add to dashboard Cite

Light-harvesting complex I (LHCI), which serves as a peripheral antenna for photosystem I (PSI) in green plants, consists mainly of four polypeptides, Lhca1-4. We report room temperature emission properties of individual reconstituted monomeric Lhca proteins (Lhca1, -2, -3, and -4) and dimeric Lhca1/4, performed by steady-state and time-resolved fluorescence techniques. The emission quantum yields of the samples are approximately 0.12, 0.085, 0.081, 0.041, and 0.063 for Lhca1, -2, -3, -4, and the -1/4 dimer, respectively, which is considerably lower than the value of 0.22 found for light-harvesting complex II (LHCII), the main peripheral antenna complex of photosystem II in green plants. The decay components of LHCI proteins can be divided in two categories: Lhca1 and Lhca3 have decay times of 1.1-1.6 ns and 3.3-3.6 ns, and Lhca2 and Lhca4 have decay times of 0.7-0.9 ns and 3.1-3.2 ns. These categories seem to correlate with the pigment composition of the samples. All decay times are faster than that observed previously for LHCII. When the absolute emission yields and the lifetimes of the Lhca samples are combined, the overall emission properties of the individual Lhca proteins are expressed in terms of their emitting dipole moment strength. In the samples without extreme red states, that is, Lhca1 and Lhca2, the emitting dipole moment has a value close to unity (relative to monomeric chlorophyll in acetone), which is similar to that for LHCII, whereas, in the samples with the red-most state (F-730), that is, Lhca3, -4, and the -1/4 dimer, the emitting dipole moment has a value less than unity (0.6-0.8), which can be explained by mixing the red-most (exciton) state with a dark charge-transfer state, as suggested in previous PSI red pigment studies. In addition, we find a lifetime component of ∼50-150 ps in all red-pigment-containing samples, which cannot be due to "slow" energy transfer, but is instead assigned to an unrelaxed state of the pigment-protein, which, on this time-scale, is converted into the final emitting state.

show abstract

“…1994; Connelly et al 1997;Barzda et al 2001;Palacios et al 2002). It seems that the number of components depends on sample preparation.…”

Section: Fluorescence Lifetimes Of the Isoformsmentioning

confidence: 99%

“…However, whereas in the spectra reported by Caffarri et al Lhcb1 exhibits more fluorescence than Lhcb2 and Lhcb3 at wavelengths between 685 and 700 nm, that is not the case in the spectra reported by Standfuss and Ku¨hlbrandt, where Lhcb2 appears to be the one fluorescing more at those wavelengths. Time-resolved fluorescence measurements have only been reported for reconstituted Lhcb1 and for native LHC II complexes (Ide et al 1987;Bittner et al 1994;Connelly et al 1997;Vasile´v et al 1997;Barzda et al 2001;Moya et al 2001;Palacios et al 2002). Whereas for the former complexes two components were reported (Moya et al 2001), for the latter a single component or two have been found (Ide et al 1987;Bittner et al 1994;Connelly et al 1997;Vasil'ev et al 1997;Barzda et al 2001;Palacios et al 2002).…”

Section: Introductionmentioning

confidence: 99%

A comparison of the three isoforms of the light-harvesting complex II using transient absorption and time-resolved fluorescence measurements

et al. 2006

View full text Add to dashboard Cite

In this article we report the characterization of the energy transfer process in the reconstituted isoforms of the plant light-harvesting complex II. Homotrimers of recombinant Lhcb1 and Lhcb2 and monomers of Lhcb3 were compared to native trimeric complexes. We used low-intensity femtosecond transient absorption (TA) and time-resolved fluorescence measurements at 77 K and at room temperature, respectively, to excite the complexes selectively in the chlorophyll b absorption band at 650 nm with 80 fs pulses and on the high-energy side of the chlorophyll a absorption band at 662 nm with 180 fs pulses. The subsequent kinetics was probed at 30-35 different wavelengths in the region from 635 to 700 nm. The rate constants for energy transfer were very similar, indicating that structurally the three isoforms are highly homologous and that probably none of them play a more significant role in light-harvesting and energy transfer. No signature has been found in the transient absorption measurements at 77 K for Lhcb3 which might suggest that this protein acts as a relative energy sink of the excitations in heterotrimers of Lhcb1/Lhcb2/Lhcb3. Minor differences in the amplitudes of some of the rate constants and in the absorption and fluorescence properties of some pigments were observed, which are ascribed to slight variations in the environment surrounding some of the chromophores depending on the isoform. The decay of the fluorescence was also similar for the three isoforms and multi-exponential, characterized by two major components in the ns regime and a minor one in the ps regime. In agreement with previous transient absorption measurements on native LHC II complexes, Chl b fi Chl a energy transfer exhibited very fast channels but at the same time a slow component (ps). The Chls absorbing at around 660 nm exhibited both fast energy transfer which we ascribe to transfer from 'red' Chl b towards 'red' Chl a and slow transfer from 'blue' Chl a towards 'red' Chl a. The results are discussed in the context of the new available atomic models for LHC II.

show abstract

Singlet–Singlet Annihilation Kinetics in Aggregates and Trimers of LHCII

Cited by 143 publications

References 76 publications

Excitation energy transfer in native and unstacked thylakoid membranes studied by low temperature and ultrafast fluorescence spectroscopy

Excitation energy transfer in native and unstacked thylakoid membranes studied by low temperature and ultrafast fluorescence spectroscopy

Excitation Decay Pathways of Lhca Proteins: A Time-Resolved Fluorescence Study

A comparison of the three isoforms of the light-harvesting complex II using transient absorption and time-resolved fluorescence measurements

Contact Info

Product

Resources

About