3ar4

Calcium pump crystal structure with bound ATP and TG in the absence of Ca2+

spinqualitylabelsall models 3ar4, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ar4 is a 1 chain structure with sequence from Oryctolagus cuniculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.15Å Ligands: ACE, ATP, MG, NA, PTY, TG1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function AT2A1_RABIT This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol to the sarcoplasmic reticulum lumen. Contributes to calcium sequestration involved in muscular excitation/contraction (By similarity). Publication Abstract from PubMed Trinitrophenyl derivatives of adenine nucleotides are widely used for probing ATP-binding sites. Here we describe crystal structures of Ca(2+)-ATPase, a representative P-type ATPase, in the absence of Ca(2+) with bound ATP, trinitrophenyl-ATP, -ADP, and -AMP at better than 2.4-A resolution, stabilized with thapsigargin, a potent inhibitor. These crystal structures show that the binding mode of the trinitrophenyl derivatives is distinctly different from the parent adenine nucleotides. The adenine binding pocket in the nucleotide binding domain of Ca(2+)-ATPase is now occupied by the trinitrophenyl group, and the side chains of two arginines sandwich the adenine ring, accounting for the much higher affinities of the trinitrophenyl derivatives. Trinitrophenyl nucleotides exhibit a pronounced fluorescence in the E2P ground state but not in the other E2 states. Crystal structures of the E2P and E2 approximately P analogues of Ca(2+)-ATPase with bound trinitrophenyl-AMP show that different arrangements of the three cytoplasmic domains alter the orientation and water accessibility of the trinitrophenyl group, explaining the origin of "superfluorescence." Thus, the crystal structures demonstrate that ATP and its derivatives are highly adaptable to a wide range of site topologies stabilized by a variety of interactions. Trinitrophenyl derivatives bind differently from parent adenine nucleotides to Ca2+-ATPase in the absence of Ca2+,Toyoshima C, Yonekura SI, Tsueda J, Iwasawa S Proc Natl Acad Sci U S A. 2011 Jan 14. PMID:21239683 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also ATPase 3D structures

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