Multi-wavelength analytical ultracentrifugation of biopolymer mixtures and interactions

Multi-wavelength analytical ultracentrifugation (MW-AUC) is a recent development made possible by new analytical ultracentrifuge optical systems. MW-AUC extends the basic hydrodynamic information content of AUC and provides access to a wide range of new applications for biopolymer characterization, and is poised to become an essential analytical tool to study macromolecular interactions. It adds an orthogonal spectral dimension to the traditional hydrodynamic characterization by exploiting unique chromophores in analyte mixtures that may or may not interact. Here we illustrate the utility of MW-AUC for experimental investigations where the benefit of the added spectral dimension provides critical information that is not accessible, and impossible to resolve with traditional AUC methods. We demonstrate the improvements in resolution and information content obtained by this technique compared to traditional single- or dual-wavelength approaches, and discuss experimental design considerations and limitations of the method. We further address the advantages and disadvantages of the two MW optical systems available today, and the differences in data analysis strategies between the two systems.

Automated summary

Multi-wavelength analytical ultracentrifugation (MW-AUC) is a new method that extends the basic information content of AUC and provides new applications for biopolymer characterization. By using unique chromophores in analyte mixtures, MW-AUC adds a spectral dimension that offers critical information not accessible through traditional methods. This article demonstrates the improvements of this technique compared to traditional approaches, discusses experimental design considerations and limitations, and addresses the differences between the two available MW optical systems.