From light-harvesting to photoprotection: structural basis of the dynamic switch of the major antenna complex of plants (LHCII)

N. Liguori, X. Periole, S.J. Marrink, R. Croce

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Light-Harvesting Complex II (LHCII) is largely responsible for light absorption and excitation energy transfer in plants in light-limiting conditions, while in high-light it participates in photoprotection. It is generally believed that LHCII can change its function by switching between different conformations. However, the underlying molecular picture has not been elucidated yet. The available crystal structures represent the quenched form of the complex, while solubilized LHCII has the properties of the unquenched state. To determine the structural changes involved in the switch and to identify potential quenching sites, we have explored the structural dynamics of LHCII, by performing a series of microsecond Molecular Dynamics simulations. We show that LHCII in the membrane differs substantially from the crystal and has the signatures that were experimentally associated with the light-harvesting state. Local conformational changes at the N-terminus and at the xanthophyll neoxanthin are found to strongly correlate with changes in the interactions energies of two putative quenching sites. In particular conformational disorder is observed at the terminal emitter resulting in large variations of the excitonic coupling strength of this chlorophyll pair. Our results strongly support the hypothesis that light-harvesting regulation in LHCII is coupled with structural changes.
Original languageEnglish
Article number15661
Pages (from-to)15661
JournalScientific Reports
Volume5
DOIs
Publication statusPublished - 2015

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switches
antennas
quenching
dynamic structural analysis
chlorophylls
electromagnetic absorption
emitters
energy transfer
signatures
disorders
molecular dynamics
membranes
crystal structure
excitation
crystals

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title = "From light-harvesting to photoprotection: structural basis of the dynamic switch of the major antenna complex of plants (LHCII)",
abstract = "Light-Harvesting Complex II (LHCII) is largely responsible for light absorption and excitation energy transfer in plants in light-limiting conditions, while in high-light it participates in photoprotection. It is generally believed that LHCII can change its function by switching between different conformations. However, the underlying molecular picture has not been elucidated yet. The available crystal structures represent the quenched form of the complex, while solubilized LHCII has the properties of the unquenched state. To determine the structural changes involved in the switch and to identify potential quenching sites, we have explored the structural dynamics of LHCII, by performing a series of microsecond Molecular Dynamics simulations. We show that LHCII in the membrane differs substantially from the crystal and has the signatures that were experimentally associated with the light-harvesting state. Local conformational changes at the N-terminus and at the xanthophyll neoxanthin are found to strongly correlate with changes in the interactions energies of two putative quenching sites. In particular conformational disorder is observed at the terminal emitter resulting in large variations of the excitonic coupling strength of this chlorophyll pair. Our results strongly support the hypothesis that light-harvesting regulation in LHCII is coupled with structural changes.",
author = "N. Liguori and X. Periole and S.J. Marrink and R. Croce",
year = "2015",
doi = "10.1038/srep15661",
language = "English",
volume = "5",
pages = "15661",
journal = "Scientific Reports",
issn = "2045-2322",
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}

From light-harvesting to photoprotection: structural basis of the dynamic switch of the major antenna complex of plants (LHCII). / Liguori, N.; Periole, X.; Marrink, S.J.; Croce, R.

In: Scientific Reports, Vol. 5, 15661, 2015, p. 15661.

Research output: Contribution to JournalArticleAcademicpeer-review

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T1 - From light-harvesting to photoprotection: structural basis of the dynamic switch of the major antenna complex of plants (LHCII)

AU - Liguori, N.

AU - Periole, X.

AU - Marrink, S.J.

AU - Croce, R.

PY - 2015

Y1 - 2015

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AB - Light-Harvesting Complex II (LHCII) is largely responsible for light absorption and excitation energy transfer in plants in light-limiting conditions, while in high-light it participates in photoprotection. It is generally believed that LHCII can change its function by switching between different conformations. However, the underlying molecular picture has not been elucidated yet. The available crystal structures represent the quenched form of the complex, while solubilized LHCII has the properties of the unquenched state. To determine the structural changes involved in the switch and to identify potential quenching sites, we have explored the structural dynamics of LHCII, by performing a series of microsecond Molecular Dynamics simulations. We show that LHCII in the membrane differs substantially from the crystal and has the signatures that were experimentally associated with the light-harvesting state. Local conformational changes at the N-terminus and at the xanthophyll neoxanthin are found to strongly correlate with changes in the interactions energies of two putative quenching sites. In particular conformational disorder is observed at the terminal emitter resulting in large variations of the excitonic coupling strength of this chlorophyll pair. Our results strongly support the hypothesis that light-harvesting regulation in LHCII is coupled with structural changes.

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