Structures of ABC transporters: handle with care.

In the past two decades, the ATP-binding cassette (ABC) transporters' field has undergone a structural revolution. The importance of structural biology to the development of the field of ABC transporters cannot be overstated, as the ensemble of structures not only revealed the architecture of ABC transporters but also shaped our mechanistic view of these remarkable molecular machines. Nevertheless, we advocate that the mechanistic interpretation of the structures is not trivial and should be carried out with prudence. Herein, we bring several examples of structures of ABC transporters that merit re-interpretation via careful comparison to experimental data. We propose that it is of the upmost importance to place new structures within the context of the available experimental data.