Effect of Beta-Gal on incorporation / interaction with lipid bilayers (SUV): analytical ultracentrifugation(AUC) and dynamic light scattering (DLS) approaches.

PEDRO D. CLOP; MARIA A. PERILLO

Santiago del Estero

Congreso; XLIV Reunión Anual SAB 2015; 2015

Sociedad Aregentina de Biof{isica

Beta-galactosidase(Beta-Gal)is a glycosylhydrolase which hydrolyzes the Beta-glycosidic bond formed between a galactose and its organic moiety(aglycone). In our laboratory we are studying the modulation of the activity of Beta-Gal in heterogeneous systems, and we have shown that the interaction of this enzyme with lipid bilayers induce changes in the activity of the enzyme on soluble substrates, depending on the composition, the curvature, the molecular packing of the membrane, and consequently, the type of lipid-protein interaction (adsorption or penetration)that could be established.To understand the effects ofincorporation/interaction of Beta-Gal with lipid bilayers, we use smallunilamellar vesicles (SUV) from egg phosphatidylcholine (egg PC), a lipid thathas no lateral segregation phase at the temperature studied. The Beta-Gal-SUVs interaction, was analyzed by analytical ultracentrifugation (UCA) and dynamiclight scattering (DLS). Experimental data allowed us to determine the hydrodynamicparameters of pure Beta-Gal (sedimentation coefficient, S=15; Stokes radius R=6.9nm and diffusion coefficient, D= 3.05 10-7 cm2/s) which resulted similarwhen mixed with SUVs, from which it could be inferred that UCA and DLS seem notto be able to resolve and/or stabilize Beta-Gal-SUV interaction in theconditions studied.