Crystallization of the bovine ADP/ATP carrier is critically dependent upon the detergent-to-protein ratio.

The ADP/ATP carrier is an integral membrane protein located in the mitochondrial inner membrane. It mediates the exchange of cytosolic ADP for ATP generated in the mitochondrial matrix. Here, the purification and crystallization of the bovine ADP/ATP carrier in complex with the inhibitor carboxyatractyloside in the presence of LAPAO, an aminoxide detergent, is reported. High-quality crystals were only obtained when excess detergent was removed to reach a controlled detergent-to-protein ratio.