Effectof -Galonincorporation / interactionwithlipidbilayers (SUV): analyticalultracentrifugation(AUC) and dynamiclightscattering (DLS) approaches.

CLOP PD; PERILLO MA

Santiago del Estero

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Biofísica (SAB); 2015

Sociedad Argentina de Biofísica

β-galactosidase(β-Gal) is a glycosylhydrolasewhichhydrolyzestheβ-glycosidic bondformedbetween a galactose and itsorganicmoiety(aglycone). In ourlaboratorywe arestudyingthemodulation of theactivity of β-Gal inheterogeneoussystems, and wehaveshownthattheinteraction ofthisenzymewithlipidbilayers induce changes in theactivity of theenzymeonsoluble substrates, dependingonthecomposition, thecurvature, the molecularpacking of themembrane, and consequently, thetype of lipid-proteininteraction(adsorptionorpenetration) thatcould beestablished.Tounderstandthe effects of incorporation/interactionof β-Gal withlipidbilayers, we use smallunilamellarvesicles (SUV)fromeggphosphatidylcholine(egg PC), a lipid that has no lateral segregationphase atthetemperaturestudied. Theβ-Gal-SUVsinteraction, wasanalyzedbyanalyticalultracentrifugation(UCA) and dynamic light scattering(DLS).Experimental data allowedusto determinethehydrodynamicparametersof pure β-Gal (sedimentationcoefficient, S=15; Stokes radius R= 6.9nmanddiffusioncoefficient, D= 3.05 10-7 cm2/s) whichresulted similar when mixed with SUVs, fromwhichitcouldbe inferredthat UCA and DLSseemnotto be abletoresolve and/orstabilizeβ-Gal-SUVinteraction in theconditionsstudied.