2Q8X

The high-resolution crystal structure of ixt6, a thermophilic, intracellular xylanase from G. stearothermophilus


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.190 
  • R-Value Observed: 0.150 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Structure-specificity relationships of an intracellular xylanase from Geobacillus stearothermophilus

Solomon, V.Teplitsky, A.Shulami, S.Zolotnitsky, G.Shoham, Y.Shoham, G.

(2007) Acta Crystallogr D Biol Crystallogr 63: 845-859

  • DOI: https://doi.org/10.1107/S0907444907024845
  • Primary Citation of Related Structures:  
    2Q8X

  • PubMed Abstract: 

    Geobacillus stearothermophilus T-6 is a thermophilic Gram-positive bacterium that produces two selective family 10 xylanases which both take part in the complete degradation and utilization of the xylan polymer. The two xylanases exhibit significantly different substrate specificities. While the extracellular xylanase (XT6; MW 43.8 kDa) hydrolyzes the long and branched native xylan polymer, the intracellular xylanase (IXT6; MW 38.6 kDa) preferentially hydrolyzes only short xylo-oligosaccharides. In this study, the detailed three-dimensional structure of IXT6 is reported, as determined by X-ray crystallography. It was initially solved by molecular replacement and then refined at 1.45 A resolution to a final R factor of 15.0% and an R(free) of 19.0%. As expected, the structure forms the classical (alpha/beta)(8) fold, in which the two catalytic residues (Glu134 and Glu241) are located on the inner surface of the central cavity. The structure of IXT6 was compared with the highly homologous extracellular xylanase XT6, revealing a number of structural differences between the active sites of the two enzymes. In particular, structural differences derived from the unique subdomain in the carboxy-terminal region of XT6, which is completely absent in IXT6. These structural modifications may account for the significant differences in the substrate specificities of these otherwise very similar enzymes.


  • Organizational Affiliation

    Department of Inorganic Chemistry and the Laboratory for Structural Chemistry and Biology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
intra-cellular xylanase
A, B
331Geobacillus stearothermophilusMutation(s): 0 
Gene Names: XYNA2
EC: 3.2.1.8
UniProt
Find proteins for Q09LY9 (Geobacillus stearothermophilus)
Explore Q09LY9 
Go to UniProtKB:  Q09LY9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ09LY9
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download Ideal Coordinates CCD File 
D [auth A]
E [auth A]
F [auth A]
G [auth A]
H [auth A]
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
N [auth B],
O [auth B],
P [auth B],
Q [auth B]
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
NA
Query on NA

Download Ideal Coordinates CCD File 
C [auth A],
M [auth B]
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.190 
  • R-Value Observed: 0.150 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 169.481α = 90
b = 80.579β = 91.89
c = 79.054γ = 90
Software Package:
Software NamePurpose
SHELXL-97refinement
SCALEPACKdata scaling
CNSrefinement
SHELXrefinement
PDB_EXTRACTdata extraction
CNSphasing
DENZOdata reduction

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-05-20
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.2: 2017-10-18
    Changes: Refinement description
  • Version 1.3: 2019-07-24
    Changes: Data collection, Refinement description
  • Version 1.4: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description