Thermo-optically induced reorganizations in the main light harvesting antenna of plants. II. Indications for the role of LHCII-only macrodomains in thylakoids.

We have investigated the circular dichroism spectral transients associated with the light-induced reversible reorganizations in chirally organized macrodomains of pea thylakoid membranes and loosely stacked lamellar aggregates of the main chlorophyll a/b light harvesting complexes (LHCII) isolated from the same membranes. These reorganizations have earlier been assigned to originate from a thermo-optic effect. According to the thermo-optic mechanism, fast local thermal transients due to dissipation of the excess excitation energy induce elementary structural changes in the close vicinity of the dissipation [Cseh et al.