Since a single biophysical technique is limited in the number of observable properties, one promising approach is the simultaneous consideration of data from multiple biophysical techniques. Following this principle, one important goal is develop a robust and general computational framework for the global analysis of binding studies of triple (or higher) protein mixtures conducted with different techniques. In the past, we have developed for this purpose a data analysis program SEDPHAT for the global analysis of data from sedimentation velocity, sedimentation equilibrium, dynamic light scattering, isothermal titration calorimetry, and surface binding. It is now widely used in the biophysical community for data analysis of protein interactions, and the possibility for a combined analysis of data from different techniques is being increasingly recognized and exploited. We have continued our experiments with model proteins to establish how data from different techniques can best be combined in a global analysis, and which statistical weight should be given. Since strict statistical rules do not lead to reasonable results, empirical weights must be assigned, and we have made progress in the development of rational rules. Further, we have extended the set of tools to include fluorescence anisotropy measurements, as well as linear spectroscopy, such as fluorescence or circular dichroism spectroscopy. We are in the process of testing the utility of these techniques in the global analysis context.
