Probing the Average Local Structure of Biomolecules Using Small-Angle Scattering and Scaling Laws

Small-angle neutron and x-ray scattering have become invaluable tools for probing the nanostructure of molecules in solution. It was recently shown that the definite integral of the scattering profile exhibits a scaling (power-law) behavior with respect to molecular mass. We derive the origin of this relationship, and discuss how the integrated scattering profile can be used to identify differing levels of disorder over local ?30 Å length scales. We apply our analysis to globular and intrinsically disordered proteins.