Conformational Characterization of Calmodulin by Hydrogen Deuterium Exchange Mass Spectrometry (HDX MS)

IN T RO DU C T IO N Correct protein conformation is essential for proper biological function of protein therapeutics. Changes in protein conformation are a major concern in the biopharmaceutical industry and conformational characterization is a difficult task. Many analytical tools such as circular dichroism (CD), differential scanning calorimetry (DSC), and analytical ultracentrifugation (AUC) are used to study the higher-order structure of proteins. These methods sample global conformation and cannot determine where conformational changes occur. Nuclear magnetic resonance (NMR) and X-ray crystallography determine protein structure with high spatial resolution, but both technologies require substantial amounts of sample and are not routinely applied to biopharmaceutical products due to the significant time and effort required.