2CXG

CYCLODEXTRIN GLYCOSYLTRANSFERASE COMPLEXED TO THE INHIBITOR ACARBOSE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.187 

wwPDB Validation   3D Report Full Report


This is version 3.1 of the entry. See complete history


Literature

X-ray structure of cyclodextrin glycosyltransferase complexed with acarbose. Implications for the catalytic mechanism of glycosidases.

Strokopytov, B.Penninga, D.Rozeboom, H.J.Kalk, K.H.Dijkhuizen, L.Dijkstra, B.W.

(1995) Biochemistry 34: 2234-2240

  • DOI: https://doi.org/10.1021/bi00007a018
  • Primary Citation of Related Structures:  
    2CXG

  • PubMed Abstract: 

    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)


  • Organizational Affiliation

    BIOSON Research Institute, University of Groningen, The Netherlands.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CYCLODEXTRIN GLYCOSYLTRANSFERASE686Niallia circulansMutation(s): 0 
EC: 2.4.1.19
UniProt
Find proteins for P43379 (Niallia circulans)
Explore P43379 
Go to UniProtKB:  P43379
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP43379
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose
B, D
2N/A
Glycosylation Resources
GlyTouCan:  G07411ON
GlyCosmos:  G07411ON
Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-D-quinovopyranose-(1-4)-alpha-D-glucopyranose
C
2N/A
Glycosylation Resources
GlyTouCan:  G96906VH
GlyCosmos:  G96906VH
Entity ID: 4
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose
E
4N/A
Glycosylation Resources
GlyTouCan:  G87171PZ
GlyCosmos:  G87171PZ
GlyGen:  G87171PZ
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
GLC
Query on GLC

Download Ideal Coordinates CCD File 
G [auth A]alpha-D-glucopyranose
C6 H12 O6
WQZGKKKJIJFFOK-DVKNGEFBSA-N
ACI
Query on ACI

Download Ideal Coordinates CCD File 
F [auth A]6-AMINO-4-HYDROXYMETHYL-CYCLOHEX-4-ENE-1,2,3-TRIOL
C7 H13 N O4
XPHOBMULWMGEBA-VZFHVOOUSA-N
CA
Query on CA

Download Ideal Coordinates CCD File 
H [auth A],
I [auth A]
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
Biologically Interesting Molecules (External Reference) 2 Unique
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.187 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 120.887α = 90
b = 111.903β = 90
c = 65.748γ = 90
Software Package:
Software NamePurpose
MADNESdata collection
BIOMOLdata reduction
TNTrefinement
MADNESdata reduction
BIOMOLdata scaling
TNTphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-10-14
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2017-10-25
    Changes: Atomic model, Derived calculations, Structure summary
  • Version 2.1: 2018-04-18
    Changes: Data collection
  • Version 3.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary
  • Version 3.1: 2023-08-09
    Changes: Database references, Refinement description, Structure summary