Structure of the Type Three Secretion System Export Gate (360G-Wellcome-109136_Z_15_A)

I will study the mechanism of protein export in the injectisome by elucidating the structure of one of its central components, the export gate. The injectisome is a large, molecular nanomachine which injects effector proteins into cells of the hosts of many bacterial pathogens. The export gate is the protein channel at the heart of this syringe-like type three secretion system (T3SS), and the structure of this channel will provide important insight into how it may function: For example, the complex may be actively involved in guiding substrates across the inner membrane or merely provide a passive conduit for unfolded proteins. In addition, there is the question of how such a complex may be "plugged" during periods of inactivity. I have recombinantly produced the export gate complex from the injectisome and also from the flagellum which possesses a related T3SS (rotation reports), and the tools of structural biology will continue to be used on them. Furthermore, I will purify larger complexes, consisting of the export gate and other T3SS proteins. This will enable me to study the structure and interactions between the gate and subunits such as the substrate specificity switch.