1CGY

SITE DIRECTED MUTATIONS OF THE ACTIVE SITE RESIDUE TYROSINE 195 OF CYCLODEXTRIN GLYXOSYLTRANSFERASE FROM BACILLUS CIRCULANS STRAIN 251 AFFECTING ACTIVITY AND PRODUCT SPECIFICITY


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Observed: 0.162 

wwPDB Validation   3D Report Full Report


This is version 2.0 of the entry. See complete history


Literature

Site-directed mutations in tyrosine 195 of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 affect activity and product specificity.

Penninga, D.Strokopytov, B.Rozeboom, H.J.Lawson, C.L.Dijkstra, B.W.Bergsma, J.Dijkhuizen, L.

(1995) Biochemistry 34: 3368-3376

  • DOI: https://doi.org/10.1021/bi00010a028
  • Primary Citation of Related Structures:  
    1CGV, 1CGW, 1CGX, 1CGY

  • PubMed Abstract: 

    Tyrosine 195 is located in the center of the active site cleft of cyclodextrin glycosyltransferase (EC 2.4.1.19) from Bacillus circulans strain 251. Alignment of amino acid sequences of CGTases and alpha-amylases, and the analysis of the binding mode of the substrate analogue acarbose in the active site cleft [Strokopytov, B., et al. (1995) Biochemistry 34, (in press)], suggested that Tyr195 plays an important role in cyclization of oligosaccharides. Tyr195 therefore was replaced with Phe (Y195F), Trp (Y195W), Leu (Y195L), and Gly (Y195G). Mutant proteins were purified and crystallized, and their X-ray structures were determined at 2.5-2.6 angstrum resolution, allowing a detailed comparison of their biochemical properties and three-dimensional structures with those of the wild-type CGTase protein. The mutant proteins possessed significantly reduced cyclodextrin forming and coupling activities but were not negatively affected in the disproportionation and saccharifying reactions. Also under production process conditions, after a 45 h incubation with a 10% starch solution, the Y195W, Y195L, and Y195G mutants showed a lower overall conversion of starch into cyclodextrins. These mutants produced a considerable amount of linear maltooligosaccharides. The presence of aromatic amino acids (Tyr or Phe) at the Tyr195 position thus appears to be of crucial importance for an efficient cyclization reaction, virtually preventing the formation of linear products. Mass spectrometry of the Y195L reaction mixture, but not that of the other mutants and the wild type, revealed a shift toward the synthesis (in low yields) of larger products, especially of beta- and gamma- (but no alpha-) cyclodextrins and minor amounts of delta-, epsilon-, zeta- and eta-cyclodextrins.(ABSTRACT TRUNCATED AT 250 WORDS)


  • Organizational Affiliation

    Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Haren, The Netherlands.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CYCLOMALTODEXTRIN GLUCANOTRANSFERASE686Niallia 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, C, D
2N/A
Glycosylation Resources
GlyTouCan:  G07411ON
GlyCosmos:  G07411ON
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download Ideal Coordinates CCD File 
E [auth A],
F [auth A]
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Observed: 0.162 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 120.184α = 90
b = 110.701β = 90
c = 66.207γ = 90
Software Package:
Software NamePurpose
PROLSQrefinement
TNTrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1995-02-07
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Database references, Derived calculations, Non-polymer description, Other, Structure summary