A research team has investigated the transport mechanism of a bacterial membrane protein using an artificially produced antibody fragment. The transport proteins, called ABC exporters, are present, for instance, in the cell membranes of bacteria and in large quantities in cancer cells and are responsible for transporting small molecules out of the cells. Some transporters can pump antibiotics or chemotherapy agents out of the cells, thus rendering therapies ineffective. In the current study, researchers showed how the transport mechanism can be blocked.