2ixf

Crystal structure of the ATPase domain of TAP1 with ATP (D645Q, Q678H mutant)

spinqualitylabelsall models 2ixf, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2ixf is a 4 chain structure with sequence from Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: ATP, GOL, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TAP1_RAT Involved in the transport of antigens from the cytoplasm to the endoplasmic reticulum for association with MHC class I molecules. Also acts as a molecular scaffold for the final stage of MHC class I folding, namely the binding of peptide. Nascent MHC class I molecules associate with TAP via tapasin (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The ABC transporter associated with antigen processing (TAP) shuttles cytosolic peptides into the endoplasmic reticulum for loading onto class I MHC molecules. Transport is fueled by ATP binding and hydrolysis at two distinct cytosolic ATPase sites. One site comprises consensus motifs shared among most ABC transporters, while the second has substituted, degenerate motifs. Biochemical and crystallography experiments with a TAP cytosolic domain demonstrate that the consensus ATPase site has high catalytic activity and facilitates ATP-dependent dimerization of the cytosolic domains, which is an important conformational change during transport. In contrast, the degenerate site is defective in dimerization and ATP hydrolysis. Full-length TAP mutagenesis demonstrates the necessity for at least one consensus site, supporting our conclusion that the consensus site is the principal facilitator of substrate transport. Since asymmetry of the ATPase site motifs is a feature of many mammalian homologs, our proposed model has broad implications for ABC transporters. Distinct structural and functional properties of the ATPase sites in an asymmetric ABC transporter.,Procko E, Ferrin-O'Connell I, Ng SL, Gaudet R Mol Cell. 2006 Oct 6;24(1):51-62. PMID:17018292 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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