View source for 2cxg


==CYCLODEXTRIN GLYCOSYLTRANSFERASE COMPLEXED TO THE INHIBITOR ACARBOSE==
<StructureSection load='2cxg' size='340' side='right'caption='[[2cxg]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2cxg]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Niallia_circulans Niallia circulans]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1cxg 1cxg]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2CXG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2CXG FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACI:6-AMINO-4-HYDROXYMETHYL-CYCLOHEX-4-ENE-1,2,3-TRIOL'>ACI</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=G6D:6-DEOXY-ALPHA-D-GLUCOSE'>G6D</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=PRD_900001:alpha-maltose'>PRD_900001</scene>, <scene name='pdbligand=PRD_900010:alpha-maltotetraose'>PRD_900010</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2cxg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2cxg OCA], [https://pdbe.org/2cxg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2cxg RCSB], [https://www.ebi.ac.uk/pdbsum/2cxg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2cxg ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CDGT2_NIACI CDGT2_NIACI] 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/cx/2cxg_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2cxg ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Crystals of cyclodextrin glycosyltransferase (CGTase) from Bacillus circulans strain 251 were soaked in buffer solutions containing the pseudotetrasaccharide acarbose, a strong amylase- and CGTase inhibitor. The X-ray structure of the complex was elucidated at 2.5-A resolution with a final crystallographic R value of 15.8% for all data between 8.0 and 2.5 A. Acarbose is bound near the catalytic residues Asp229, Glu257, and Asp328. The carboxylic group of Glu257 is at hydrogen bonding distance from the glycosidic oxygen in the scissile bond between the B and C sugars (residue A is at the nonreducing end of the inhibitor). Asp328 makes hydrogen bonds with the 4-amino-4,6-dideoxyglucose (residue B), and Asp229 is in a close van der Waals contact with the C1 atom of this sugar. From this we conclude that in CGTase Glu257 acts as the proton donor and Asp229 serves as the general base or nucleophile, while Asp328 is involved in substrate binding and may be important for elevating the pKa of Glu257. On the basis of these results it appears that the absence of the C6-hydroxyl group in the B sugar is responsible for the inhibitory properties of acarbose on CGTase. This suggests that the C6-hydroxyl group of this sugar plays an essential role in the catalytic mechanism of CGTase.(ABSTRACT TRUNCATED AT 250 WORDS)

X-ray structure of cyclodextrin glycosyltransferase complexed with acarbose. Implications for the catalytic mechanism of glycosidases.,Strokopytov B, Penninga D, Rozeboom HJ, Kalk KH, Dijkhuizen L, Dijkstra BW Biochemistry. 1995 Feb 21;34(7):2234-40. PMID:7857935<ref>PMID:7857935</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2cxg" style="background-color:#fffaf0;"></div>

==See Also==
*[[Glycosyltransferase 3D structures|Glycosyltransferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Niallia circulans]]
[[Category: Dijkstra BW]]
[[Category: Ruiterkamp R]]
[[Category: Strokopytov BV]]
[[Category: Uitdehaag JCM]]