Beschreibung:
<jats:title>Significance</jats:title>
<jats:p>Here we report the crystal structures of an amino acid ATP-binding cassette (ABC) importer either in its apo form or in complex with substrates (Arg, His) and/or ATPs. Interestingly, each transmembrane domain has a negatively charged pocket, allowing amino acids carrying positively charged groups to pass through. Functional analyses of the transporter in proteoliposomes indicate its capability to undergo substrate-dependent conformational changes resulting in stimulated ATPase activity. Taken together, we identified a previously undefined substrate binding mode of ABC transporters and shed light on the mechanism underlying how ABC transporters select and translocate their substrates.</jats:p>