Some bacterial membrane transporters work almost like freight elevators to transport substances through the cell membrane into the interior of the cell. The transporter itself spans the bacterial membrane. Like a forklift, a soluble protein outside the bacterium transports the substance to the „elevator“ and unloads its cargo there. The freight elevator transports it to the inside of the cell, in other words to another floor. Researchers at the University Hospital Bonn (UKB) and the University of Bonn, in collaboration with a team from the University of York, have now studied the interaction between the transporter and its soluble substrate binding protein.