1CGV

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å

wwPDB Validation 3D Report Full Report


This is version 1.3 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

  • Primary Citation of Related Structures:  

  • 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 ...

    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)


    Related Citations: 
    • Nucleotide Sequence and X-Ray Structure of Cyclodextrin Glycosyltransferase from Bacillus Circulans Strain 251 in a Maltose-Dependent Crystal Form
      Lawson, C.L.L.,Van Montfort, R.,Strokopytov, B.,Rozeboom, H.J.,Kalk, K.H.,De Vries, G.E.,Penninga, D.,Dijkhuizen, L.,Dijkstra, B.W.
      (1994) J.Mol.Biol. 236: 590
    • Maltodextrin-Dependent Crystallization of Cyclomaltodextrin Glucanotransferase from Bacillus Circulans
      Lawson, C.L.L.,Bergsma, J.,Bruinenberg, P.M.,De Vries, G.E.,Dijkhuizen, L.,Dijkstra, B.W.
      (1990) J.Mol.Biol. 214: 807


    Organizational Affiliation

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CYCLOMALTODEXTRIN GLUCANOTRANSFERASE
A
686Bacillus circulansMutation(s): 1 
Gene Names: cgt
EC: 2.4.1.19
Find proteins for P43379 (Bacillus circulans)
Go to UniProtKB:  P43379
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MAL
Query on MAL

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Download CCD File 
A
MALTOSE
C12 H22 O11
GUBGYTABKSRVRQ-ASMJPISFSA-N
 Ligand Interaction
CA
Query on CA

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Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 121.031α = 90.00
b = 111.107β = 90.00
c = 66.302γ = 90.00
Software Package:
Software NamePurpose
TNTrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1995-02-27
    Type: Initial release
  • Version 1.1: 2008-03-03
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2011-12-07
    Type: Database references