Substrate-modulated ADP/ATP-transporter dynamics revealed by NMR relaxation dispersion.

ABSTRACT: The ADP/ATP carrier (AAC) transports ADP and ATP across the inner mitochondrial membrane. Unlike most transporters, which have two-fold direct or inverted quasisymmetry, AAC has apparent three-fold rotational symmetry. Further, its transport rate is relatively fast for transporters that carry large solutes. Here, we study the yeast AAC carrier 3 by obtaining comprehensive NMR relaxation dispersion measurements, which provide residue-specific information on the protein's conformational exchange. Our data indicate that AAC is predominantly in the cytosol-facing open state and converts to a sparsely populated state in an asymmetric manner despite its three-fold structural symmetry. Binding of the substrate ADP substantially increases the rate of conformational exchange, whereas the inhibitor

SUBMITTER: Bruschweiler S 

PROVIDER: S-EPMC4527935 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature