Structure and Fractal Dimension of Protein-Detergent Complexes

Small-angle neutron-scattering experiments were made on bovine serum albumin (BSA)-lithium dodecyl sulfate (LDS) complexes in buffer solutions. As increasing amounts of LDS are added, the scattering data indicate that BSA molecules are successively transformed into random coil conformations with LDS forming globular micelles randomly decorating the polypeptide backbones. A cross-section formula is developed which successfully fits small-angle neutron-scattering spectra over the entire $Q$ range. The fractal dimension, the micellar size, and the extent of the denatured protein are simultaneously extracted.