INSTITUTO DE FISICA DE LIQUIDOS Y SISTEMAS BIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Unveiling the role of surfactants on amyloid-like protein self-assembling
SCANAVACHI, G.; ITRI, R; RUSO, J.; YANIS RICARDO ESPINOSA SILVA
Congreso; XLII Brazilian Biophysics Society Congress; 2017
Some proteins can undergo structural changes that may trigger an aggregation process where they self-assembly into highly ordered aggregates called amyloid fibers. In vivo, these amyloid fibers are related to more than 25 different diseases, some of them are lethal as Creutzfeldt-Jakob disease and others can lead a person to incapacities, as diabetes type II, Alzheimer´s and Parkinson´s diseases. With the aim of understanding the conditions and mechanisms by which proteins form amyloid fibers, we mixed bovine serum albumin (BSA) at pH 3.7 with sodium dodecyl sulfate (SDS) and sodium perfluorooctanoate (SPFO) to induce the amyloid fibers formation. BSA conformational changes were followed in order to suggest a possible pathway of aggregation. Turbidity(UV-VIS spectroscopy) and Thioflavin T fluorescence data revealed, respectively, the presence of large aggregates and the formation of amyloid-like fibers as the surfactant concentration increased, whereas circular dichroism (CD) showed that BSA second structure changes from α-helix to β-sheet. Transmission electron microscopy (TEM) permitted us to obtain images of fibers and aggregates in the micrometers scale. Further, small angle x-ray scattering (SAXS) measurements provided information about the protein?s quaternary structure as a function of surfactant concentration and a more detailed analysis allowed us to suggest a pathway of fibrillation process. Lastly, we performed molecular dynamics simulations to obtain an all atom structure of BSA at pH 3.7and to study the influence of SDS and SPFO in the BSA conformation.