TY - JOUR
T1 - Excitation dynamics in Photosystem i from Chlamydomonas reinhardtii. Comparative studies of isolated complexes and whole cells
AU - Giera, Wojciech
AU - Szewczyk, Sebastian
AU - McConnell, Michael D.
AU - Snellenburg, Joris
AU - Redding, Kevin
AU - Van Grondelle, Rienk
AU - Gibasiewicz, Krzysztof
N1 - Funding Information:
The research leading to these results has received funding from LASERLAB-EUROPE II : grant agreement no. 228334 . K.G. gratefully acknowledges financial support from the Polish government (scientific project no. N N202 085440 ). K.R. gratefully acknowledges support from the U.S. National Science Foundation (grant MCB-1052573 ). J.S. acknowledges support from BioSolar Cells , cofinanced by the Dutch Ministry of Economic Affairs, Agriculture and Innovation . W.G. is a scholarship holder within the project “Integrated program supporting the development of the Adam Mickiewicz University in Poznan in the field of physical sciences: Pro-innovative education, competent staff, graduates of the future” (POKL.04.01.01-00-133/09-00, Sub-measure 4.1.1 of the Human Capital Operational Programme, co-financed by European Union under the European Social Fund).
PY - 2014/10
Y1 - 2014/10
N2 - Identical time-resolved fluorescence measurements with ∼ 3.5-ps resolution were performed for three types of PSI preparations from the green alga, Chlamydomonas reinhardtii: isolated PSI cores, isolated PSI-LHCI complexes and PSI-LHCI complexes in whole living cells. Fluorescence decay in these types of PSI preparations has been previously investigated but never under the same experimental conditions. As a result we present consistent picture of excitation dynamics in algal PSI. Temporal evolution of fluorescence spectra can be generally described by three decay components with similar lifetimes in all samples (6-8 ps, 25-30 ps, 166-314 ps). In the PSI cores, the fluorescence decay is dominated by the two fastest components (∼ 90%), which can be assigned to excitation energy trapping in the reaction center by reversible primary charge separation. Excitation dynamics in the PSI-LHCI preparations is more complex because of the energy transfer between the LHCI antenna system and the core. The average trapping time of excitations created in the well coupled LHCI antenna system is about 12-15 ps longer than excitations formed in the PSI core antenna. Excitation dynamics in PSI-LHCI complexes in whole living cells is very similar to that observed in isolated complexes. Our data support the view that chlorophylls responsible for the long-wavelength emission are located mostly in LHCI. We also compared in detail our results with the literature data obtained for plant PSI.
AB - Identical time-resolved fluorescence measurements with ∼ 3.5-ps resolution were performed for three types of PSI preparations from the green alga, Chlamydomonas reinhardtii: isolated PSI cores, isolated PSI-LHCI complexes and PSI-LHCI complexes in whole living cells. Fluorescence decay in these types of PSI preparations has been previously investigated but never under the same experimental conditions. As a result we present consistent picture of excitation dynamics in algal PSI. Temporal evolution of fluorescence spectra can be generally described by three decay components with similar lifetimes in all samples (6-8 ps, 25-30 ps, 166-314 ps). In the PSI cores, the fluorescence decay is dominated by the two fastest components (∼ 90%), which can be assigned to excitation energy trapping in the reaction center by reversible primary charge separation. Excitation dynamics in the PSI-LHCI preparations is more complex because of the energy transfer between the LHCI antenna system and the core. The average trapping time of excitations created in the well coupled LHCI antenna system is about 12-15 ps longer than excitations formed in the PSI core antenna. Excitation dynamics in PSI-LHCI complexes in whole living cells is very similar to that observed in isolated complexes. Our data support the view that chlorophylls responsible for the long-wavelength emission are located mostly in LHCI. We also compared in detail our results with the literature data obtained for plant PSI.
KW - Chlamydomonas reinhardtii
KW - Light harvesting complex I
KW - Photosystem I
KW - Red chlorophylls
KW - Streak camera
KW - Time-resolved fluorescence
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U2 - 10.1016/j.bbabio.2014.06.004
DO - 10.1016/j.bbabio.2014.06.004
M3 - Article
C2 - 24973599
AN - SCOPUS:84905884775
SN - 0005-2728
VL - 1837
SP - 1756
EP - 1768
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
IS - 10
ER -