4I5R

Crystal structure of a fungal chimeric cellobiohydrolase Cel6A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.181 
  • R-Value Work: 0.154 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Engineered thermostable fungal Cel6A and Cel7A cellobiohydrolases hydrolyze cellulose efficiently at elevated temperatures.

Wu, I.Arnold, F.H.

(2013) Biotechnol.Bioeng. 110: 1874-1883

  • DOI: 10.1002/bit.24864
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Thermostability is an important feature in industrial enzymes: it increases biocatalyst lifetime and enables reactions at higher temperatures, where faster rates and other advantages ultimately reduce the cost of biocatalysis. Here we report the ther ...

    Thermostability is an important feature in industrial enzymes: it increases biocatalyst lifetime and enables reactions at higher temperatures, where faster rates and other advantages ultimately reduce the cost of biocatalysis. Here we report the thermostabilization of a chimeric fungal family 6 cellobiohydrolase (HJPlus) by directed evolution using random mutagenesis and recombination of beneficial mutations. Thermostable variant 3C6P has a half-life of 280 min at 75°C and a T(50) of 80.1°C, a ~15°C increase over the thermostable Cel6A from Humicola insolens (HiCel6A) and a ~20°C increase over that from Hypocrea jecorina (HjCel6A). Most of the mutations also stabilize the less-stable HjCel6A, the wild-type Cel6A closest in sequence to 3C6P. During a 60-h Avicel hydrolysis, 3C6P released 2.4 times more cellobiose equivalents at its optimum temperature (T(opt)) of 75°C than HiCel6A at its T(opt) of 60°C. The total cellobiose equivalents released by HiCel6A at 60°C after 60 h is equivalent to the total released by 3C6P at 75°C after ~6 h, a 10-fold reduction in hydrolysis time. A binary mixture of thermostable Cel6A and Cel7A hydrolyzes Avicel synergistically and released 1.8 times more cellobiose equivalents than the wild-type mixture, both mixtures assessed at their respective T(opt). Crystal structures of HJPlus and 3C6P, determined at 1.5 and 1.2 Å resolution, indicate that the stabilization comes from improved hydrophobic interactions and restricted loop conformations by introduced proline residues.


    Organizational Affiliation

    Division of Chemistry and Chemical Engineering, California Institute of Technology 210-41, Pasadena, CA 91125, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Chimeric cel6A
A
364Chaetomium thermophilumHypocrea jecorinaHumicola insolens
This entity is chimeric
Mutation(s): 0 
Gene Names: cbh2, cel6A (avi2)
EC: 3.2.1.- 3.2.1.91 3.2.1.91
Find proteins for Q5G2D4 (Chaetomium thermophilum)
Go to UniProtKB:  Q5G2D4
Find proteins for P07987 (Hypocrea jecorina)
Go to UniProtKB:  P07987
Find proteins for Q9C1S9 (Humicola insolens)
Go to UniProtKB:  Q9C1S9
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download SDF File 
Download CCD File 
A
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
EDO
Query on EDO

Download SDF File 
Download CCD File 
A
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
PG4
Query on PG4

Download SDF File 
Download CCD File 
A
TETRAETHYLENE GLYCOL
C8 H18 O5
UWHCKJMYHZGTIT-UHFFFAOYSA-N
 Ligand Interaction
PGE
Query on PGE

Download SDF File 
Download CCD File 
A
TRIETHYLENE GLYCOL
C6 H14 O4
ZIBGPFATKBEMQZ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.181 
  • R-Value Work: 0.154 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 158.610α = 90.00
b = 45.262β = 95.21
c = 58.602γ = 90.00
Software Package:
Software NamePurpose
MOLREPphasing
PDB_EXTRACTdata extraction
REFMACrefinement
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2012-11-28 
  • Released Date: 2013-04-03 
  • Deposition Author(s): Arnold, F.H., Wu, I.

Revision History 

  • Version 1.0: 2013-04-03
    Type: Initial release
  • Version 1.1: 2013-06-12
    Type: Database references
  • Version 1.2: 2017-08-09
    Type: Refinement description, Source and taxonomy