A new semiempirical procedure is presented which relates solution small-angle X-ray scattering parameters to sedimentation coefficients. With this method, sedimentation coefficients were calculated for a set of 20 globular macromolecules with molecular weights ranging from 1.3 × 104to 7.0 × 106; all were in excellent agreement with experimental values. Best results were arrived at by obtaining: (1) the Stokes radius in Svedberg's equation by way of the scattering volume V of the macromolecule instead of the commonly used partial specific volume v̄; and (2) the structural frictional ratio ( f f0)sfrom an axial ratio derived from RGS V instead of the usual 3V (4πRG3relationship, where RGis the radius of gyration and S is the external surface area of the molecule. This indicates that the frictional ratio is a function of the surface roughness of the macromolecule, in agreement with similar conclusions in the literature. In addition, structural parameters from the X-ray crystallographic structure are compared with those from small-angle X-ray scattering for a better insight into the contribution of hydration to the frictional coefficient. © 1982.
Kumosinski, T. F., & Pessen, H. (1982). Estimation of sedimentation coefficients of globular proteins: An application of small-angle X-ray scattering. Archives of Biochemistry and Biophysics, 219(1), 89–100. https://doi.org/10.1016/0003-9861(82)90137-0