TY - JOUR
T1 - Capturing the Quenching Mechanism of Light-Harvesting Complexes of Plants by Zooming in on the Ensemble
AU - Mascoli, Vincenzo
AU - Liguori, Nicoletta
AU - Xu, Pengqi
AU - Roy, Laura M.
AU - van Stokkum, Ivo H.M.
AU - Croce, Roberta
PY - 2019/11/14
Y1 - 2019/11/14
N2 - The light-harvesting complexes (LHCs) of plants can regulate the energy flux to the reaction centers in response to fluctuating light by virtue of their vast conformational landscape. They do so by switching from a light-harvesting state to a quenched state, dissipating the excess absorbed energy as heat. However, isolated LHCs are prevalently in their light-harvesting state, which makes the identification of their photoprotective mechanism extremely challenging. Here, ensemble time-resolved fluorescence experiments show that monomeric CP29, a minor LHC of plants, exists in various emissive states with identical spectra but different lifetimes. The photoprotective mechanism active in a subpopulation of strongly quenched complexes is further investigated via ultrafast transient absorption spectroscopy, kinetic modeling, and mutational analysis. We demonstrate that the observed quenching is due to excitation energy transfer from chlorophylls to a dark state of the centrally bound lutein.
AB - The light-harvesting complexes (LHCs) of plants can regulate the energy flux to the reaction centers in response to fluctuating light by virtue of their vast conformational landscape. They do so by switching from a light-harvesting state to a quenched state, dissipating the excess absorbed energy as heat. However, isolated LHCs are prevalently in their light-harvesting state, which makes the identification of their photoprotective mechanism extremely challenging. Here, ensemble time-resolved fluorescence experiments show that monomeric CP29, a minor LHC of plants, exists in various emissive states with identical spectra but different lifetimes. The photoprotective mechanism active in a subpopulation of strongly quenched complexes is further investigated via ultrafast transient absorption spectroscopy, kinetic modeling, and mutational analysis. We demonstrate that the observed quenching is due to excitation energy transfer from chlorophylls to a dark state of the centrally bound lutein.
KW - antenna quenching
KW - carotenoids
KW - energy transfer
KW - light harvesting
KW - mutational analysis
KW - photoprotection
KW - photosynthesis
KW - SDG15: Life on land
KW - SDG7: Affordable and clean energy
KW - target kinetic modeling
KW - time-resolved electronic spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85074666001&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85074666001&partnerID=8YFLogxK
U2 - 10.1016/j.chempr.2019.08.002
DO - 10.1016/j.chempr.2019.08.002
M3 - Article
AN - SCOPUS:85074666001
VL - 5
SP - 2900
EP - 2912
JO - Chem
JF - Chem
SN - 2451-9308
IS - 11
ER -