1EGN

CELLOBIOHYDROLASE CEL7A (E223S, A224H, L225V, T226A, D262G) MUTANT


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.240 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

Engineering of a glycosidase Family 7 cellobiohydrolase to more alkaline pH optimum: the pH behaviour of Trichoderma reesei Cel7A and its E223S/ A224H/L225V/T226A/D262G mutant.

Becker, D.Braet, C.Brumer III, H.Claeyssens, M.Divne, C.Fagerstrom, B.R.Harris, M.Jones, T.A.Kleywegt, G.J.Koivula, A.Mahdi, S.Piens, K.Sinnott, M.L.Stahlberg, J.Teeri, T.T.Underwood, M.Wohlfahrt, G.

(2001) Biochem.J. 356: 19-30


  • PubMed Abstract: 
  • The crystal structures of Family 7 glycohydrolases suggest that a histidine residue near the acid/base catalyst could account for the higher pH optimum of the Humicola insolens endoglucanase Cel7B, than the corresponding Trichoderma reesei enzymes. M ...

    The crystal structures of Family 7 glycohydrolases suggest that a histidine residue near the acid/base catalyst could account for the higher pH optimum of the Humicola insolens endoglucanase Cel7B, than the corresponding Trichoderma reesei enzymes. Modelling studies indicated that introduction of histidine at the homologous position in T. reesei Cel7A (Ala(224)) required additional changes to accommodate the bulkier histidine side chain. X-ray crystallography of the catalytic domain of the E223S/A224H/L225V/T226A/D262G mutant reveals that major differences from the wild-type are confined to the mutations themselves. The introduced histidine residue is in plane with its counterpart in H. insolens Cel7B, but is 1.0 A (=0.1 nm) closer to the acid/base Glu(217) residue, with a 3.1 A contact between N(epsilon2) and O(epsilon1). The pH variation of k(cat)/K(m) for 3,4-dinitrophenyl lactoside hydrolysis was accurately bell-shaped for both wild-type and mutant, with pK(1) shifting from 2.22+/-0.03 in the wild-type to 3.19+/-0.03 in the mutant, and pK(2) shifting from 5.99+/-0.02 to 6.78+/-0.02. With this poor substrate, the ionizations probably represent those of the free enzyme. The relative k(cat) for 2-chloro-4-nitrophenyl lactoside showed similar behaviour. The shift in the mutant pH optimum was associated with lower k(cat)/K(m) values for both lactosides and cellobiosides, and a marginally lower stability. However, k(cat) values for cellobiosides are higher for the mutant. This we attribute to reduced non-productive binding in the +1 and +2 subsites; inhibition by cellobiose is certainly relieved in the mutant. The weaker binding of cellobiose is due to the loss of two water-mediated hydrogen bonds.


    Related Citations: 
    • The Three-dimensional Crystal Structure of the Catalytic Core of Cellobiohydrolase I from Trichoderma reesei
      Divne, C.,Stahlberg, J.,Reinikainen, T.,Ruohonen, L.,Pettersson, G.,Knowles, J.K.,Teeri, T.T.,Jones, T.A.
      (1994) Science 265: 524
    • 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

    Department of Paper Science, University of Manchester Institute of Science and Technology, P.O. Box 88, Sackville Street, Manchester M60 lQD, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
1,4-BETA-D-GLUCAN CELLOBIOHYDROLASE CEL7A
A
434Hypocrea jecorinaMutation(s): 5 
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: 0.270 
  • R-Value Work: 0.240 
  • Space Group: I 2 2 2
Unit Cell:
Length (Å)Angle (°)
a = 83.110α = 90.00
b = 83.340β = 90.00
c = 110.610γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
CNSrefinement
CNSphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-05-16
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance
  • Version 1.3: 2018-01-24
    Type: Database references
  • Version 1.4: 2018-01-31
    Type: Database references