1HJQ

Structure of two fungal beta-1,4-galactanases: searching for the basis for temperature and pH optimum.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.55 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.199 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Structure of Two Fungal Beta-1,4-Galactanases: Searching for the Basis for Temperature and Ph Optimum

Le Nours, J.Ryttersgaard, C.Lo Leggio, L.Ostergaard, P.R.Borchert, T.V.Christensen, L.L.H.Larsen, S.

(2003) Protein Sci 12: 1195

  • DOI: 10.1110/ps.0300103
  • Primary Citation of Related Structures:  
    1HJQ, 1HJU, 1HJS

  • PubMed Abstract: 
  • beta-1,4-Galactanases hydrolyze the galactan side chains that are part of the complex carbohydrate structure of the pectin. They are assigned to family 53 of the glycoside hydrolases and display significant variations in their pH and temperature optimum and stability ...

    beta-1,4-Galactanases hydrolyze the galactan side chains that are part of the complex carbohydrate structure of the pectin. They are assigned to family 53 of the glycoside hydrolases and display significant variations in their pH and temperature optimum and stability. Two fungal beta-1,4-galactanases from Myceliophthora thermophila and Humicola insolens have been cloned and heterologously expressed, and the crystal structures of the gene products were determined. The structures are compared to the previously only known family 53 structure of the galactanase from Aspergillus aculeatus (AAGAL) showing approximately 56% identity. The M. thermophila and H. insolens galactanases are thermophilic enzymes and are most active at neutral to basic pH, whereas AAGAL is mesophilic and most active at acidic pH. The structure of the M. thermophila galactanase (MTGAL) was determined from crystals obtained with HEPES and TRIS buffers to 1.88 A and 2.14 A resolution, respectively. The structure of the H. insolens galactanase (HIGAL) was determined to 2.55 A resolution. The thermostability of MTGAL and HIGAL correlates with increase in the protein rigidity and electrostatic interactions, stabilization of the alpha-helices, and a tighter packing. An inspection of the active sites in the three enzymes identifies several amino acid substitutions that could explain the variation in pH optimum. Examination of the activity as a function of pH for the D182N mutant of AAGAL and the A90S/ H91D mutant of MTGAL showed that the difference in pH optimum between AAGAL and MTGAL is at least partially associated with differences in the nature of residues at positions 182, 90, and/or 91.


    Organizational Affiliation

    Centre for Crystallographic Studies, Department of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
BETA-1,4-GALACTANASEA332Humicola insolensMutation(s): 0 
EC: 3.2.1.89
UniProt
Find proteins for P83691 (Humicola insolens)
Explore P83691 
Go to UniProtKB:  P83691
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download Ideal Coordinates CCD File 
B [auth A]2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.55 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.199 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.254α = 90
b = 68.955β = 90
c = 135.16γ = 90
Software Package:
Software NamePurpose
CNSrefinement
SCALEPACKdata scaling
EPMRphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-07-25
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-17
    Changes: Data collection
  • Version 1.4: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Other, Structure summary