The function of protein-based drugs strongly depends on three-dimensional structures. Conformational changes such as protein denaturation generally result in the loss of drug potency and the alternation of the pharmacological properties of the product. Thus, physicochemical characterizations of the higher-order structures of protein drugs are very important to drug development. Methods that allow fast determination of protein conformations or conformation changes in drug formulations for protein therapeutics are of high value.
Here we present a study that uses a novel ion mobility mass spectrometer, the Waters® SYNAPT™ High Definition Mass Spectrometry™ (HDMS™) System, to probe the conformational structures of a model protein, cytochrome c. Results demonstrate that the instrument is a powerful tool for resolving the population of coexisting conformational states of cytochrome c and for revealing the conformational changes induced by the addition of acid or organic solvent, thus providing direct evidence that the protein is denatured.