PLoS Pathog. 6: e1001129 (2010)

The Dot/Icm type IVB secretion system (T4BSS) is a pivotal determinant of Legionella pneumophila pathogenesis. Here, we report the crystal structure of DotD, a core component of the Dot/Icm T4BSS. The structure is remarkably similar to that of an N-terminal subdomain of secretins, integral outer membrane proteins that form substrate conduits for the type II and type III secretion systems (T2SS and T3SS). This uncovers an intriguing link between T4BSS and T2SS/T3SS.