1cxe: Difference between revisions

Revision as of 13:13, 2 May 2008

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

OverviewOverview

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.

About this StructureAbout this Structure

1CXE is a Single protein structure of sequence from Bacillus circulans. Full crystallographic information is available from OCA.

ReferenceReference

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 Page seeded by OCA on Fri May 2 13:13:02 2008

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OCA

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 [[Image:1cxe.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 1cxe |SIZE=350|CAPTION= <scene name='initialview01'>1cxe</scene>, resolution 2.1&Aring;
+The line below this paragraph, containing "STRUCTURE_1cxe", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=GLC:GLUCOSE'>GLC</scene>, <scene name='pdbligand=MAL:MALTOSE'>MAL</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Cyclomaltodextrin_glucanotransferase Cyclomaltodextrin glucanotransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.19 2.4.1.19] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE=
+-->
-|DOMAIN=
+{{STRUCTURE_1cxe|  PDB=1cxe  |  SCENE=  }}
-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1cxe FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1cxe OCA], [http://www.ebi.ac.uk/pdbsum/1cxe PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1cxe RCSB]</span>
-}}
 '''COMPLEX OF CGTASE WITH MALTOTETRAOSE AT ROOM TEMPERATURE AND PH 9.1 BASED ON DIFFRACTION DATA OF A CRYSTAL SOAKED WITH ALPHA-CYCLODEXTRIN'''
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 [[Category: Knegtel, R M.A.]]
 [[Category: Strokopytov, B V.]]
-[[Category: glycosyltransferase]]
+[[Category: Glycosyltransferase]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 13:13:02 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 19:30:26 2008''