Structural heterogeneity and substrate engagement mechanism of the bacterial proteasome activator Bpa

Bpa (bacterial proteasome activator) is essential for Mycobacterium tuberculosis virulence, yet its structural heterogeneity and mode of substrate engagement have remained poorly understood. Here, the authors combine hydrogen/deuterium exchange mass spectrometry and solution NMR spectroscopy to elucidate Bpa assembly and its interaction with a model substrate.