1cxe

COMPLEX OF CGTASE WITH MALTOTETRAOSE AT ROOM TEMPERATURE AND PH 9.1 BASED ON DIFFRACTION DATA OF A CRYSTAL SOAKED WITH ALPHA-CYCLODEXTRIN

spinqualitylabelsall models 1cxe, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1cxe is a 1 chain structure with sequence from Niallia circulans. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.1Å Ligands: CA, GLC, PRD_900001, PRD_900010 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CDGT2_NIACI 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 Asp-229, Glu-257, and Asp-328 constitute the catalytic residues in cyclodextrin glycosyl transferase from Bacillus circulans strain 251. Via site-directed mutagenesis constructed D229N, E257Q, and D328N mutant proteins showed a 4,000-60,000-fold reduction of cyclization activity. A D229N/E257Q double mutant showed a 700,000-fold reduction and was crystallized for use in soaking experiments with alpha-cyclodextrin. Crystal structures were determined of wild type CGTase soaked at elevated pH with alpha-cyclodextrin (resolution, 2.1 A) and maltoheptaose (2.4 A). In addition, structures at cryogenic temperature were solved of the unliganded enzyme (2.2 A) and of the D229N/E257Q mutant after soaking with alpha-cyclodextrin (2.6 A). In the crystals soaked in alpha-cyclodextrin and maltoheptaose, a maltotetraose molecule is observed to bind in the active site. Residue 229 is at hydrogen bonding distance from the C-6 hydroxyl group of the sugar, which after cleavage will contain the new reducing end. In the D229N/E257Q double mutant structure, two alpha-cyclodextrins are observed to replace two maltoses at the E-domain, thus providing structural information on product inhibition via binding to the enzyme's raw starch binding domain. Crystallographic studies of the interaction of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 with natural substrates and products.,Knegtel RM, Strokopytov B, Penninga D, Faber OG, Rozeboom HJ, Kalk KH, Dijkhuizen L, Dijkstra BW J Biol Chem. 1995 Dec 8;270(49):29256-64. PMID:7493956 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Glycosyltransferase 3D structures

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