cholesterol, oxysterols, lipid transfer, lipid exchange, lipid flip-flop
Though cholesterol is the most prevalent and essential sterol in mammalian cellular membranes, its precursors, post-synthesis cholesterol products, as well as its oxidized derivatives play many other important physiological roles. Using a non-invasive in situ technique, time-resolved small angle neutron scattering, we report on the rate of membrane desorption and corresponding activation energy for this process for a series of sterol precursors and post-synthesis cholesterol products that vary from cholesterol by the number and position of double bonds in B ring of cholesterol’s steroid core. In addition, we report on sterols that have oxidation modifications in ring A and ring B of the steroid core. We find that sterols that differ in position or the number of double bonds in ring B have similar time and energy characteristics, while oxysterols have faster transfer rates and lower activation energies than cholesterol in a manner generally consistent with known sterol characteristics, like Log P, the n-octanol/water partitioning coefficient. We find, however, that membrane/water partitioning which is dependent on lipid-sterol interactions is a better predictor, shown by the correlation of the sterols’ tilt modulus with both the desorption rates and activation energy.
Source Publication Title
Journal of Membrane Biology
Perez-Salas, U., Porcar, L., Garg, S., Ayee-Leong, M. A., & Levitan, I. (2022). Effective Parameters Controlling Sterol Transfer: A Time‑Resolved Small‑Angle Neutron Scattering Study. Journal of Membrane Biology, 255, 423. https://doi.org/10.1007/s00232-022-00231-3