Colloquium Speaker: Stephen Wassall
Polyunsaturated Fatty Acids do not Like Cholesterol: A Role in Membrane Organization
Polyunsaturated fatty acids (PUFA) are structurally distinguished from more common less unsaturated fatty acids by the presence of a repeating =C-C-C= motif that produces an extremely flexible chain rapidly isomerising through conformational states. This talk will focus on the profound impact that the high disorder of PUFA has on the interaction of cholesterol with the membrane phospholipids into which they incorporate. Results obtained with model membranes using solid state 2H NMR spectroscopy complemented by X-ray and neutron diffraction, detergent extraction and calorimetry will be presented. They demonstrate that PUFA and cholesterol have a mutual aversion that drives lateral segregation of the sterol between membrane (raft and non-raft) domains. Changes in molecular organization produced within these domains of specific lipid composition have the potential to modulate the activity of resident proteins for which they serve as a platform. We hypothesize that here lies, in part, the origin of the plethora of health benefits conferred by dietary consumption of PUFA notably found in fish oils.