Bovine serum albumin refolding at acid solution by small angle neutron scattering

Abstract

A series of study of the conformational change of bovine serum albumin (BSA) induced by pH and additive has been conducted by small angle scattering (SANS) technique. The unfolding process occur by increasing the solvent acidity of the buffer. The previous work from SANS scattering profile shows that BSA unfolded into a cylinder-like structure at pH 2. In this work, the role of sorbitol in refolding process of BSA in acid solution was studied. Sorbitol, at concentrations from 0 to 3 M, led to the progressive restoration of BSA globular structure. The SANS scattering data show the conformational change from cylinder-like structure of pure BSA at pH 2 undergo to ellipsoid-like structure in the addition of 3M sorbitol. In the absence, 1M and 2M sorbitol, the SANS scattering profile of BSA fitted to flexible cylinder model. Meanwhile in the present of 3M sorbitol, it fitted to triaxial ellipsoid model. These results are confirmed with ab initio low-resolution shape calculation model analysis using GNOM and DAMMIN obtaining the three-dimensional structure model.