(2c) A Multidimensional Spectroscopy Approach for Protein Characterization

Aggregation and oligomerization processes lead to structural changes in proteins that have high relevance in the biomedical and biotechnology fields. Understanding of the mechanisms through which proteins unfold and aggregate is critical for pharmaceutical applications, specifically for the understanding of the relationship between protein structure and drug effectiveness. To date, the information required for this understanding comes from diverse, albeit well established, methods such as crystallography, light scattering (both static and dynamic), circular dichroism, NMR, chromatography and other optical methods including absorption and fluorescence spectroscopy. Because the information from these methods cannot be interpreted concurrently, only partial monitoring of experimental and process variables can be accomplished in real-time for both dynamic experimentation and process monitoring. In this study, a multidimensional spectroscopy platform for the simultaneous measurement and interpretation of multiwavelength angular scattering,  orescence, and transmission measurements is demonstrated. This platform s capable of real-time continuous measurements of proteins in solution. The associated integrated interpretation model translates the multidimensional spectral data into useful physical and chemical information such as oligomeric and aggregate types and size distributions, chromophoric amino acid composition, and the response of fluorophores, such as tyrosine and tryptophan, to their local environment. The quantity and quality of the information accessible through multidimensional spectroscopy measurements is demonstrated using NIST traceable particle size standards, and the thermal and chemical denaturation of proteins as case studies. The results indicate that  multidimensional spectroscopy is a powerful and exciting approach for accurate, rapid, identification and characterization of proteins and protein related processes.