2wsk | pdb_00002wsk

Crystal structure of Glycogen Debranching Enzyme GlgX from Escherichia coli K-12

spinqualitylabelsall models 2wsk, resolution 2.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2wsk is a 1 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.25Å Ligands: SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function GLGX_ECOLI Hydrolyzes the alpha-1,6-glucosidic linkages in glycogen which has first been partially depolymerized by phosphorylase. Shows only very little activity with native glycogen. 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 Glycogen serves as major energy storage in most living organisms. GlgX, with its gene in the glycogen degradation operon, functions in glycogen catabolism by selectively catalyzing the debranching of polysaccharide outer chains in bacterial glycosynthesis. GlgX hydrolyzes alpha-1,6-glycosidic linkages of phosphorylase-limit dextrin containing only three or four glucose subunits produced by glycogen phosphorylase. To understand its mechanism and unique substrate specificity toward short branched alpha-polyglucans, we determined the structure of GlgX from Escherichia Coli K12 at 2.25 A resolution. The structure reveals a monomer consisting of three major domains with high structural similarity to the subunit of TreX, the oligomeric bifunctional glycogen debranching enzyme (GDE) from Sulfolobus. In the overlapping substrate binding groove, conserved residues Leu270, Asp271, and Pro208 block the cleft, yielding a shorter narrow GlgX cleft compared to that of TreX. Residues 207-213 form a unique helical conformation that is observed in both GlgX and TreX, possibly distinguishing GDEs from isoamylases and pullulanases. The structural feature observed at the substrate binding groove provides a molecular explanation for the unique substrate specificity of GlgX for G4 phosphorylase-limit dextrin and the discriminative activity of TreX and GlgX toward substrates of varying lengths. Structural rationale for the short branched substrate specificity of the glycogen debranching enzyme GlgX.,Song HN, Jung TY, Park JT, Park BC, Myung PK, Boos W, Woo EJ, Park KH Proteins. 2010 Jun;78(8):1847-55. PMID:20187119 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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