HOS (Higher Order Structure) Analysis

Three-dimensional or higher-order structures (HOS) of protein/peptide drugs determine their function. HOS of a protein refer to its secondary, tertiary, and quaternary structure. As protein drugs are complex, it is critical to characterize the protein’s higher-order structure to understand its stability, folding, structure, and functional activity. HOS analysis is crucial in determining a biological drug’s molecular structure and critical quality attributes. Changes in HOS can impact stability, safety, quality, and efficacy, resulting in increased toxicity and loss of biological function. HOS of complex drug molecules can be characterized by many techniques such as NMR, X-ray crystallography, Circular dichroism, Mass spectrometry, FTIR, SEC-MALS, DSC, DLS, and Analytical ultracentrifugation, etc. Of late, NMR has emerged as one of the primary tools for elucidating protein structure in their formulation states. Whereas, Analytical ultracentrifugation (AUC) can report on possible aggregation state(s) and the presence of higher molecular weight species.