4ymx

Crystal structure of the substrate binding protein of an amino acid ABC transporter

spinqualitylabelsall models 4ymx, resolution 1.48Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4ymx is a 2 chain structure with sequence from Caldanaerobacter subterraneus subsp. tengcongensis MB4. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.481Å Ligands: ARG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8RCC4_CALS4 Publication Abstract from PubMed ATP-binding cassette (ABC) transporters are ubiquitous integral membrane proteins that translocate a variety of substrates, ranging from ions to macromolecules, either out of or into the cytosol (hence defined as importers or exporters, respectively). It has been demonstrated that ABC exporters and importers function through a common mechanism involving conformational switches between inward-facing and outward-facing states; however, the mechanism underlying their functions, particularly substrate recognition, remains elusive. Here we report the structures of an amino acid ABC importer Art(QN)2 from Thermoanaerobacter tengcongensis composed of homodimers each of the transmembrane domain ArtQ and the nucleotide-binding domain ArtN, either in its apo form or in complex with substrates (Arg, His) and/or ATPs. The structures reveal that the straddling of the TMDs around the twofold axis forms a substrate translocation pathway across the membrane. Interestingly, each TMD has a negatively charged pocket that together create a negatively charged internal tunnel allowing amino acids carrying positively charged groups to pass through. Our structural and functional studies provide a better understanding of how ABC transporters select and translocate their substrates. Structural basis for substrate specificity of an amino acid ABC transporter.,Yu J, Ge J, Heuveling J, Schneider E, Yang M Proc Natl Acad Sci U S A. 2015 Apr 6. pii: 201415037. PMID:25848002 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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