The light-driven reactions of oxygenic photosynthesis are carried out by five molecular complexes consisting of ~70 polypeptides associated with pigments and redox cofactors. These complexes are hosted within the thylakoid network - a membranous continuum of flattened vesicles with a complex, highly differentiated 3D morphology. The distribution of the complexes within the thylakoids, in particular of the two photosystems, is not homogeneous. This asymmetry has major structural and functional consequences and is essential for the steady-state function of the photosynthetic machinery as well as for its ability to adapt to changes in light quality and intensity. The latter ability is facilitated by redox-controlled regulatory mechanisms, known as state transitions, that counteract imbalances in electron flow between the two photosystems. State transitions are accompanied by reversible changes in the structure of the thylakoids and involve redistribution of LHC II (and possibly of other photosynthetic complexes) between the different thylakoid domains. Presently, high-resolution data on the 3D structure of the thylakoid network are not available and the distribution and spatial organization of the photosynthetic complexes within this network are not fully characterized. The macroscopic and microscopic structural changes that accompany state transitions and their evolution in time are even less defined.

Our research concentrates on determination of the 3D structure of the thylakoid network and the distribution of the photosynthetic complexes within it, at a near-molecular resolution. More recently, we began studies aimed at following the temporal evolution of the macroscopic and microscopic changes that accompany light adaptation.