pH-dependent interaction of fumonisin B1 with cholesterol: physicochemical and molecular modeling studies at the air-water interface.
Langmuir film balance technology was used to study the interaction between the mycotoxin fumonisin B1 (FB1) and cholesterol. FB1 was added in the aqueous subphase underneath a monomolecular film of cholesterol, and the interaction was measured as an increase in the surface pressure of the film. Above pH 9, a strong inhibition of the reaction was observed. Similar results were obtained with the bile salt sodium taurocholate. The FB1-cholesterol complex was reinforced by NaCl but was destabilized by NaF, a salt known to break hydrogen bonds. These data suggest that the molecular association between FB1 and cholesterol involves both hydrophobic interactions and a hydrogen bond between the NH3(+) group of FB1 and the OH group of cholesterol. Molecular mechanics simulations of the FB1-cholesterol complex were consistent with this hypothesis. These data may shed some light on the mechanisms involved in the intestinal absorption of FB1 and its biliary excretion.
Mahfoud
Radhia
R
Institut Méditerranéen de Recherche en Nutrition, UMR-INRA 1111, and Laboratoire de Synthèse Organique, Faculté des Sciences de St-Jérôme, 13397 Marseille Cedex 20, France.
Maresca
Marc
M
Santelli
Maurice
M
Pfohl-Leszkowicz
Annie
A
Puigserver
Antoine
A
Fantini
Jacques
J
D000388:Air; D002264:Carboxylic Acids / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002784:Cholesterol / Q000737:chemistry*; D037341:Fumonisins; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D013499:Surface Properties; D013656:Taurocholic Acid / Q000737:chemistry; D014867:Water
D002264:Carboxylic Acids; D037341:Fumonisins; D014867:Water; C056933:fumonisin B1; D013656:Taurocholic Acid; D002784:Cholesterol