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Article Dans Une Revue Biochimica biophysica acta (BBA) - Bioenergetics Année : 2019

Tuning antenna function through hydrogen bonds to chlorophyll a

Résumé

We describe a molecular mechanism tuning the functional properties of chlorophyll a (Chl-a) molecules in photosynthetic antenna proteins. Light-harvesting complexes from photosystem II in higher plants - specifically LHCII purified with α- or β-dodecyl-maltoside, along with CP29 - were probed by low-temperature absorption and resonance Raman spectroscopies. We show that hydrogen bonding to the conjugated keto carbonyl group of protein-bound Chl-a tunes the energy of its Soret and Qy absorption transitions, inducing red-shifts that are proportional to the strength of the hydrogen bond involved. Chls-a with non-H-bonded keto C131 groups exhibit the blue-most absorption bands, while both transitions are progressively red-shifted with increasing hydrogen-bonding strength - by up 382 & 605 cm-1 in the Qy and Soret band, respectively. These hydrogen bonds thus tune the site energy of Chl-a in light-harvesting proteins, determining (at least in part) the cascade of energy transfer events in these complexes.
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Dates et versions

hal-02281193 , version 1 (18-11-2020)

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Manuel J. Llansola-Portoles, Andrew A. Pascal, Manuel J. Llansola-Portoles, Fei Li, Pengqi Xu, et al.. Tuning antenna function through hydrogen bonds to chlorophyll a. Biochimica biophysica acta (BBA) - Bioenergetics, 2019, 1861 (4), pp.148078. ⟨10.1016/j.bbabio.2019.148078⟩. ⟨hal-02281193⟩
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