A New Possibility to Recognize the Concentration Dependence of Sedimentation Coefficients

The binding constants of self-associating proteins can be determined from sedimentation velocity runs using the numerical solution of the Lamm equation. This procedure requires good starting values of sedimentation and diffusion coefficients or their possible concentration dependencies. We found, based on fits of synthetic data files, a connection between the concentration dependence of sedimentation coefficients (ks) and the estimated radius position at the cell base (rb). Deviation of the estimated rb value from the expected one is indicating the occurrence of ks that can be estimated by the program LammNum as a prerequisite for the calculation of reliable binding constants.