2qa3 | pdb_00002qa3

Structural Studies Reveal the Inactivation of E. coli L-aspartate aminotransferase by (S)-4,5-amino-dihydro-2-thiophenecarboxylic acid (SADTA) via two mechanisms (at pH6.5)

spinqualitylabelsall models 2qa3, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2qa3 is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.75Å Ligands: GOL, KST, PMP, PSZ, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function AAT_ECOLI 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 As a mechanism-based inactivator of PLP-enzymes, (S)-4-amino-4,5-dihydro-2-thiophenecarboxylic acid (SADTA) was cocrystallized with Escherichia coli aspartate aminotransferase (l-AspAT) at a series of pH values ranging from 6 to 8. Five structural models with high resolution (1.4-1.85 A) were obtained for l-AspAT-SADTA complexes at pH 6.0, 6.5, 7.0, 7.5, and 8.0. Electron densities of the models showed that two different adducts had formed in the active sites. One adduct was formed from SADTA covalently linked to pyridoxal 5'-phosphate (PLP) while the other adduct was formed with the inhibitor covalently linked to Lysine246,1 the active site lysine. Moreover, there is a strong indication based on the electron densities that the occurrence of the two adducts is pH dependent. We conclude that SADTA inactivates l-AspAT via two different mechanisms based on the binding direction of the inactivator. Additionally, the structural models also show pH dependence of the protein structure itself, which provided detailed mechanistic implications for l-AspAT. Inactivation of Escherichia coli L-aspartate aminotransferase by (S)-4-amino-4,5-dihydro-2-thiophenecarboxylic acid reveals "a tale of two mechanisms".,Liu D, Pozharski E, Lepore BW, Fu M, Silverman RB, Petsko GA, Ringe D Biochemistry. 2007 Sep 18;46(37):10517-27. Epub 2007 Aug 22. PMID:17713924 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aspartate aminotransferase 3D structures

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