3D6E

Crystal structure of the engineered 1,3-1,4-beta-glucanase protein from Bacillus licheniformis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.210 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Re-engineering specificity in 1,3-1,4-beta-glucanase to accept branched xyloglucan substrates

Addington, T.Calisto, B.Alfonso-Prieto, M.Rovira, C.Fita, I.Planas, A.

(2011) Proteins 79: 365-375

  • DOI: 10.1002/prot.22884

  • PubMed Abstract: 
  • Family 16 carbohydrate active enzyme members Bacillus licheniformis 1,3-1,4-β-glucanase and Populus tremula x tremuloides xyloglucan endotransglycosylase (XET16-34) are highly structurally related but display different substrate specificities. Althou ...

    Family 16 carbohydrate active enzyme members Bacillus licheniformis 1,3-1,4-β-glucanase and Populus tremula x tremuloides xyloglucan endotransglycosylase (XET16-34) are highly structurally related but display different substrate specificities. Although the first binds linear gluco-oligosaccharides, the second binds branched xylogluco-oligosaccharides. Prior engineered nucleophile mutants of both enzymes are glycosynthases that catalyze the condensation between a glycosyl fluoride donor and a glycoside acceptor. With the aim of expanding the glycosynthase technology to produce designer oligosaccharides consisting of hybrids between branched xylogluco- and linear gluco-oligosaccharides, enzyme engineering on the negative subsites of 1,3-1,4-β-glucanase to accept branched substrates has been undertaken. Removal of the 1,3-1,4-β-glucanase major loop and replacement with that of XET16-34 to open the binding cleft resulted in a folded protein, which still maintained some β-glucan hydrolase activity, but the corresponding nucleophile mutant did not display glycosynthase activity with either linear or branched glycosyl donors. Next, point mutations of the 1,3-1,4-β-glucanase β-sheets forming the binding site cleft were mutated to resemble XET16-34 residues. The final chimeric protein acquired binding affinity for xyloglucan and did not bind β-glucan. Therefore, binding specificity has been re-engineered, but affinity was low and the nucleophile mutant of the chimeric enzyme did not show glycosynthase activity to produce the target hybrid oligosaccharides. Structural analysis by X-ray crystallography explains these results in terms of changes in the protein structure and highlights further engineering approaches toward introducing the desired activity.


    Related Citations: 
    • Crystal structure of Bacillus licheniformis 1,3-1,4-beta-D-glucan 4-glucanohydrolase at 1.8 A resolution
      Hahn, M.,Pons, J.,Planas, A.,Querol, E.,Heinemann, U.
      (1995) FEBS Lett. 374: 221


    Organizational Affiliation

    Laboratory of Biochemistry, Bioengineering Department, Institut Químic de Sarrià, Universitat Ramon Llull, 08017 Barcelona, Spain.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Beta-glucanase
A, B
201Bacillus licheniformisMutation(s): 13 
Gene Names: bg1
EC: 3.2.1.73
Find proteins for P27051 (Bacillus licheniformis)
Go to UniProtKB:  P27051
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.210 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 39.551α = 61.38
b = 54.813β = 85.72
c = 54.910γ = 86.10
Software Package:
Software NamePurpose
DENZOdata reduction
REFMACrefinement
SCALEPACKdata scaling
DNAdata collection
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-05-19
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance