Cholesterol Shows Preference for the Interior of Polyunsaturated Lipid Membranes

摘要

The physiological importance of polyunsaturated fatty acid (PUFA) is becoming increasingly evident. Sequestration of PUFA-containing phospholipids into cholesterol-depleted membrane domains has been hypothesized to have a role in neurological function and in alleviating a number of health problems. The dislike of highly disordered polyunsaturated chains for the planar, rigid surface of the steroid moiety is thought to be a major driving force for domain formation. Recent neutron scattering experiments showed a striking manifestation of this aversion. Selectively deuterated cholesterol/1,2-diarachidonylphosphatidylcholine (DAPC) samples revealed that the hydroxyl of the sterol resides at the center of the bilayer. This result was interpreted in terms of cholesterol preferentially sequestering inside the membrane and in contrast to its usual position where the hydroxyl group locates near the aqueous interface.