Molecular Aspects Of Structure-Function Relationships In Mitochondrial Adenine Nucleotide Carrier
This chapter focuses on molecular aspects of the ADP/ATP carrier. The adenine nucleotide carrier is, therefore, a link between the nucleotide pool of the matrix space of mitochondria and that of the cytosol. Import of the ADP/ATP carrier protein into the mitochondrial membrane requires a transmembrane potential. The carrier protein is capable of assuming conformational changes that can be probed by two specific categories of inhibitors, atractyloside (ATR) and carboxyatractyloside (CATR) on one hand, and bongkrekic acid (BA) and isobongkrekic acid (isoBA) on the other. A breakthrough in the attempt to explore the structure-function relationship in ADP/ATP transport was the finding that the carrier protein in detergent is still able to recognize substrate and inhibitory ligands, and to respond to their binding by conformational changes that are revealed, for example, by modification of the intrinsic fluorescence. The ADP/ATP carrier protein in the membrane-bound can assume two distinct conformations which differ by their reactivity to the specific inhibitors CATR and BA.