FRAGMENTATION AND SEPARATION OF THE THYLAKOID MEMBRANE - EFFECT OF LIGHT-INDUCED PROTEIN-PHOSPHORYLATION ON DOMAIN COMPOSITION

The thylakoid membrane consists of three main compartments, the stroma lamellae, the central appressed region of grana and the peripheral gr ana margins. These three domains can be separated from each other by f ragmentation and aqueous two-phase partitioning. Upon phosphorylation the light-harvesting chlorophyll alb binding complex II (LHC II) disso ciates away from photosystem II in grana and migrates into the stroma lamellae. Dynamic processes, such as lateral migration of LHC II, can be examined by analysing corresponding fragments from phosphorylated a nd non-phosphorylated thylakoids. Our results show that we can detect not only the well studied lateral migration of phosphorylated LHC II f rom grana to stroma lamellae, but also migration within the grana disc , from the core of grana to the margins of grana. Furthermore, we show that the grana margin vesicles and the stroma lamellae vesicles are h eterogeneous populations that can be fractionated further by counter-c urrent distribution.