The role and structure of mitochondrial carriers.

Members of the mitochondrial carrier family transport compounds over the inner mitochondrial membrane to link the biochemical pathways in the cytosol with those in the mitochondrial matrix. X-ray crystallography has recently provided us with the first atomic model of the bovine ADP/ATP carrier, which is a member of this family. The structure explains the typical three-fold sequence repeats and signature motif of mitochondrial carriers. However, the carrier was crystallised as a monomer in detergent, which is inconsistent with the consensus that mitochondrial carriers exist as homo-dimers. The projection structure of the yeast ADP/ATP carrier by electron crystallography shows that carriers could form homo-dimers in the membrane.