1Q2B

CELLOBIOHYDROLASE CEL7A WITH DISULPHIDE BRIDGE ADDED ACROSS EXO-LOOP BY MUTATIONS D241C AND D249C


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.207 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Engineering the exo-loop of Trichoderma reesei cellobiohydrolase, Cel7A. A comparison with Phanerochaete chrysosporium Cel7D.

von Ossowski, I.Stahlberg, J.Koivula, A.Piens, K.Becker, D.Boer, H.Harle, R.Harris, M.Divne, C.Mahdi, S.Zhao, Y.Driguez, H.Claeyssens, M.Sinnott, M.L.Teeri, T.T.

(2003) J.Mol.Biol. 333: 817-829

  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The exo-loop of Trichoderma reesei cellobiohydrolase Cel7A forms the roof of the active site tunnel at the catalytic centre. Mutants were designed to study the role of this loop in crystalline cellulose degradation. A hydrogen bond to substrate made ...

    The exo-loop of Trichoderma reesei cellobiohydrolase Cel7A forms the roof of the active site tunnel at the catalytic centre. Mutants were designed to study the role of this loop in crystalline cellulose degradation. A hydrogen bond to substrate made by a tyrosine at the tip of the loop was removed by the Y247F mutation. The mobility of the loop was reduced by introducing a new disulphide bridge in the mutant D241C/D249C. The tip of the loop was deleted in mutant Delta(G245-Y252). No major structural disturbances were observed in the mutant enzymes, nor was the thermostability of the enzyme affected by the mutations. The Y247F mutation caused a slight k(cat) reduction on 4-nitrophenyl lactoside, but only a small effect on cellulose hydrolysis. Deletion of the tip of the loop increased both k(cat) and K(M) and gave reduced product inhibition. Increased activity was observed on amorphous cellulose, while only half the original activity remained on crystalline cellulose. Stabilisation of the exo-loop by the disulphide bridge enhanced the activity on both amorphous and crystalline cellulose. The ratio Glc(2)/(Glc(3)+Glc(1)) released from cellulose, which is indicative of processive action, was highest with Tr Cel7A wild-type enzyme and smallest with the deletion mutant on both substrates. Based on these data it seems that the exo-loop of Tr Cel7A has evolved to facilitate processive crystalline cellulose degradation, which does not require significant conformational changes of this loop.


    Related Citations: 
    • Activity Studies and Crystal Structures of Catalytically Deficient Mutants of Cellobiohydrolase I from Trichoderma Reesei
      Stahlberg, J.,Divne, C.,Koivula, A.,Piens, K.,Claeyssens, M.,Teeri, T.T.,Jones, T.A.
      (1996) J.Mol.Biol. 264: 337
    • High-Resolution Crystal Structures Reveal How a Cellulose Chain is Bound in the 50A Long Tunnel of Cellobiohydrolase-I from Trichoderma Reesei
      Divne, C.,Stahlberg, J.,Teeri, T.T.,Jones, T.A.
      (1998) J.Mol.Biol. 275: 309


    Organizational Affiliation

    VTT Biotechnology, PO Box 1500, FIN-02044 VTT, Espoo, Finland.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
EXOCELLOBIOHYDROLASE I
A
434Hypocrea jecorinaMutation(s): 2 
Gene Names: cbh1
EC: 3.2.1.91
Find proteins for P62694 (Hypocrea jecorina)
Go to UniProtKB:  P62694
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download SDF File 
Download CCD File 
A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
CO
Query on CO

Download SDF File 
Download CCD File 
A
COBALT (II) ION
Co
XLJKHNWPARRRJB-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
PCA
Query on PCA
A
L-PEPTIDE LINKINGC5 H7 N O3GLU
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.207 
  • Space Group: I 2 2 2
Unit Cell:
Length (Å)Angle (°)
a = 83.170α = 90.00
b = 83.140β = 90.00
c = 110.040γ = 90.00
Software Package:
Software NamePurpose
CNSphasing
MAR345data collection
SCALEPACKdata scaling
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-11-25
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance
  • Version 1.3: 2017-10-11
    Type: Data collection, Refinement description