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 to 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 of combined analysis of data from different techniques is being increasingly recognized and exploited. Specifically, we have further extended the experimental studies on a model system, and tested the new anisotropy and spectroscopy components of the data analysis. In addition, we have incorporated more complex global analysis models for competitive and distinguishable multi-site interactions. We have developed a strategy to rationally approach the dilemma of systematic experimental errors in the different techniques, which is related to the statistical weights given to each data set in the context of the global analysis.
