(588h) Control of Insertion and Directionality of Synechocystis PCC. 6803 Photosystem I in in Vitro Liposomes
Control of Insertion and Directionality of Synechocystis PCC. 6803 Photosystem I in in vitro Liposomes
Samantha Clark1, Guru Venkatesan2, Andy Sarles2, and Paul Frymier1
Cell structure is maintained through complex interactions of phospholipids and proteins to form cell membranes. The membranes act as protective barriers against toxins and give functionality and stability to proteins embedded in the phospholipid bilayer. In cyanobacteria and green plants, photosynthetic complexes are amongst the proteins in the thylakoid membrane. These complexes are responsible for converting photons into usable energy. Photosystem I (PSI), part of this pathway, transfers electrons across the thylakoid membrane to form NADPH. Currently, PSI is predominantly studied in vitro while solubilized in detergent. Recent work in our lab has shown that the detergents used to solubilize membrane proteins has a significant effect on protein structure and dyanamics. A system where lipids provide the protection for the hydrophobic transmembrane domains is more appropriate for comparison to the natural system for PSI. In the current study, we are interested in examining the effects of membrane constituents on protein-lipid structure and dynamics. In this presentation, we examine the use of lipid vesicles to effectively simulate in vivo conditions for PSI. In particular, we are interested in how the lipid constituents affect the directionality of insertion of the protein within the lipid vesicle wall.