Calculation of hydrodynamic parameters of biopolymers from scattering data using whole-body approaches

Abstract

A calculation procedure is presented which relates solution scattering and hydrodynamic parameters. Biopolymers are modeled by whole-body approaches, approximating their overall shape by spheres or prolate/oblate ellipsoids of revolution. Molar masses, partial specific volumes, radii of gyration, volumes and surface-to-volume ratios are used for predicting sedimentation and diffusion coefficients and intrinsic viscosities of a variety of biopolymers, in addition to the derivation of several further parameters such as frictional coefficients, Simha factors, Stokes and viscosity radii. The establishment of a comprehensive set of structural and hydrodynamic data including several correlations allows the examination of observed and predicted parameters. In this context also the validity of some empirical relations was tested. A variety of roughly globular biopolymers (simple and conjugated proteins, ribonucleic acids) of different molar mass and shape have been examined. The comparisons comprise both the native states of the biopolymers under analysis and structural alterations in response to changes in environment or state of ligation. Far-reaching conformity between experimental values and anticipated parameters was achieved. Detailed error propagation calculations allow a close scrutiny of the accuracy of the parameters to be predicted.Key wordsBiopolymersanalytical ultracentrifugationviscometryscatteringparameter predictionsmodelingwhole-body approaches