NAD(H)-mediated tetramerization controls the activity of phospholipase PlaB.

The virulence factor PlaB promotes lung colonization, tissue destruction, and intracellular replication of , the causative agent of Legionnaires' disease. It is a highly active phospholipase exposed at the bacterial surface and shows an extraordinary activation mechanism by tetramer deoligomerization. To unravel the molecular basis for enzyme activation and localization, we determined the crystal structure of PlaB in its tetrameric form.