Interactons of cholesterol and 7‑ketocholesterol with unsaturated fatty acids of different unsaturation degree – The monolayer study

Publication date: Available online 9 June 2019Source: Biochimica et Biophysica Acta (BBA) - BiomembranesAuthor(s): J.L. Fidalgo Rodríguez, P. Dynarowicz-Latka, J. Miñones CondeAbstractUnsaturated fatty acids (UFAs) are known to lower the level of sterols in blood, which accounts for their cardioprotective effect. To understand the molecular basis of this effect, Langmuir monolayer studies have been performed. A series of UFAs differing in the length of the fatty acid chain and the number of double bonds (oleic acid, OA; linoleic acid, LA; stearidonic acid, SDA; eicosanoic acid, EA) were mixed with cholesterol and its more toxic oxidized derivative, 7‑ketocholesterol (7-KC), abundantly present in atheroma plaques. Strong attractive UFA-sterol interactions were attributed to the formation of “surface complexes”, in which sterol molecules are bound, thereby reducing the amount of free sterol molecules. It has been found that strength of interactions increases with the degree of unsaturation of the acyl chain in UFA molecule. The most attractive interactions correspond to mixtures with SDA containing 70 mol% of 7-KC and 50 mol% of cholesterol. In both cases, the formation of high stability complexes of, respectively, 2:1 and 1:1 sterol/SDA stoichiometry has been proposed. Other complexes of lower stability and 1:2 stoichiometry were postulated for chol (or 7-KC)/LA systems. The complexes of the lowest stability correspond to chol (or 7-KC) mixtures with OA and EA of 1...
Source: Biochimica et Biophysica Acta (BBA) Biomembranes - Category: Biochemistry Source Type: research