Ewa Janik, Joanna Bednarska, Karol Sowiński, Rafał Luchowski, Monika Zubik, Wojciech Grudziński and Wiesław I. Gruszecki

Light-induced formation of dimeric LHCII

Photosynth Res
DOI: 10.1007/s11120-017-0387-6

Abstract

It emerges from numerous experiments that LHCII, the major photosynthetic antenna complex of plants, can appear not only in the trimeric or monomeric states but also as a dimer. We address the problem whether the dimeric form of the complex is just a simple intermediate element of the trimer–monomer transformation or if it can also be a physiologically relevant molecular organization form? Dimers of LHCII were analyzed with application of native electrophoresis, time-resolved fluorescence spectroscopy, and fluorescence correlation spectroscopy. The results reveal the appearance of two types of LHCII dimers: one formed by the dissociation of one monomer
from the trimeric structure and the other formed by association of monomers into a distinctively different molecular organizational form, characterized by a high rate of chlorophyll excitation quenching. The hypothetical structure of such an energy quencher is proposed. The high lightinduced LHCII dimerization is discussed as a potential element of the photoprotective response in plants.