7taa

FAMILY 13 ALPHA AMYLASE IN COMPLEX WITH ACARBOSE

spinqualitylabelsall models 7taa, resolution 1.98Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7taa is a 1 chain structure with sequence from Aspergillus oryzae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.98Å Ligands: ABC, CA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function AMYA1_ASPOR 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 three-dimensional structure of the Aspergillus oryzae alpha-amylase (TAKA-amylase), in complex with the inhibitor acarbose, has been determined by X-ray crystallography at a resolution of 1. 98 A. The tetrasaccharide inhibitor is present as a hexasaccharide presumably resulting from a transglycosylation event. The hexasaccharide occupies the -3 to +3 subsites of the enzyme, consistent with the known number of subsites determined by kinetic studies, with the acarbose unit itself in the -1 to +3 subsites of the enzyme. The transition state mimicking unsaturated pseudo-saccharide occupies the -1 subsite as expected and is present in a distorted 2H3 half-chair conformation. Careful refinement plus extremely well-resolved unbiased electron density suggest that the hexasaccharide represents a genuine transglycosylation product, but the possibility that this apparent species results from an overlapping network of tetrasaccharides is also discussed. Catalysis by alpha-amylase involves the hydrolysis of the alpha-1,4 linkages in amylose with a net retention of the anomeric configuration, via a double-displacement mechanism, as originally outlined by Koshland [Koshland, D. E. (1953) Biol. Rev. 28, 416-336]. The enzymatic acid/base and nucleophile, residues Glu230 and Asp206, respectively, are appropriately positioned for catalysis in this complex, and the hexasaccharide species allows mapping of all the noncovalent interactions between protein and ligand through the enzyme's six subsites. Structure of the Aspergillus oryzae alpha-amylase complexed with the inhibitor acarbose at 2.0 A resolution.,Brzozowski AM, Davies GJ Biochemistry. 1997 Sep 9;36(36):10837-45. PMID:9283074 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Amylase 3D structures

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