1dhk

STRUCTURE OF PORCINE PANCREATIC ALPHA-AMYLASE

spinqualitylabelsall models 1dhk, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1dhk is a 2 chain structure with sequence from Phaseolus vulgaris and Sus scrofa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA, CL, NAG NonStd Res: PCA Activity: Alpha-amylase, with EC number 3.2.1.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [LEA1_PHAVU] Lectin and alpha-amylase inhibitor. Acts as a defensive protein against insects.[:] 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 BACKGROUND: alpha-Amylases catalyze the hydrolysis of glycosidic linkages in starch and other related polysaccharides. The alpha-amylase inhibitor (alpha-Al) from the bean Phaseolus vulgaris belongs to a family of plant defence proteins and is a potent inhibitor of mammalian alpha-amylases. The structure of pig pancreatic alpha-amylase (PPA) in complex with both a carbohydrate inhibitor (acarbose) and a proteinaceous inhibitor (Tendamistat) is known, but the catalytic mechanism is poorly understood. RESULTS: The crystal structure of pig pancreatic alpha-amylase complexed with alpha-Al was refined to 1.85 A resolution. It reveals that in complex with PPA, the inhibitor has the typical dimer structure common to legume lectins. Two hairpin loops extending out from the jellyroll fold of a monomer interact directly with the active site region of the enzyme molecule, with the inhibitor molecule filling the whole substrate-docking region of the PPA. The inhibitor makes substrate-mimetic interactions with binding subsites of the enzyme and targets catalytic residues in the active site. Binding of inhibitor induces structural changes at the active site of the enzyme. CONCLUSIONS: The present analysis reveals that there are extensive interactions between the inhibitor and residues that are highly conserved in the active site of alpha-amylases; alpha-Al1 inactivates PPA through elaborate blockage of substrate-binding sites. It provides a basis to design peptide analogue inhibitors. alpha-Amylase inhibition is of interest from several points of view, for example the treatment of diabetes and for crop protection. Substrate mimicry in the active center of a mammalian alpha-amylase: structural analysis of an enzyme-inhibitor complex.,Bompard-Gilles C, Rousseau P, Rouge P, Payan F Structure. 1996 Dec 15;4(12):1441-52. PMID:8994970 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Amylase User:Gabriel Pons/Sandbox 2

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