Most proteins, particularly those that accomplish complicated tasks, form assemblies with other proteins and molecules that are critical to their function. Established structural biology tools are most effective for highly purified samples that have limited conformational variability, which makes it challenging to apply those methods to capture a systems-wide understanding of the structures, interactions, and dynamics that are present under different cellular conditions. The Bush Lab develops and applies mass spectrometry based techniques that are fast, sensitive, and tolerant of heterogeneity for characterizing the native structures of biological assemblies.