Conformational changes on human serum albumin induced by sodium perfluooctanate in aqueous solution

MESSINA, P.V.; PRIETO, G.; BLANCO, E.; SABÍN, J.; RUSO, J.M.; SARMIENTO, F.

Utrecht

Conferencia; 6th Liquid Matter Conference; 2005

European Physical Society

Conformational changes at the bulk solution at air-aqueous interface of human serum albumin (HSA) induced by cha.nges in concentration of sodium perfiuorooctanoate (SPFO) were studied by difi'erence spectroscopy, electrophoretical mobility and by pendant drop tensiometry. Zeta--potential was use to monitored the formation of HSA -SPFO complex and the surface charge of the complexo The conformational transition of HSA at the bulk solution was followed as a function of denaturant concentration by absorbance mea.surements at 280 nm. Data wcrc analyscd to obtain vnlucs for the Gibbs energies of the transítion in water and in a hydrophobic environment pertaining to saturated protein-surfactant complexes. Conformational changes that surfactant induces on HSA molecules alter iLs absorpt.ion behaviour al, the air*wal.er inLerface. Dynruuic surface measuremenLs to evruuate this comportment was used. It was shown that at low [SPFO], proteins present three adsorption regimes; induction time, monolayer saturation and interfacial gelation. When surfactant concentration increa.ses and colúormational challge at the bulk !lOlution OCt:UN, aililorption regimes d.ú;appear. HSA lUolecule~ in l:Ln intermediate conformationru state, migrate to air-water interface and form an unique monolayer. At high [SPFO], the adsorption of denatured molecules exhibits a behaviour analogous to dilute solutions.