3VHN

Y61G mutant of Cellulase 12A from thermotoga maritima


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.189 

wwPDB Validation 3D Report Full Report



Literature

Enhanced activity of Thermotoga maritima cellulase 12A by mutating a unique surface loop

Cheng, Y.-S.Ko, T.-P.Huang, J.W.Wu, T.H.Lin, C.Y.Luo, W.Li, Q.Ma, Y.Huang, C.H.Wang, A.H.Liu, J.-R.Guo, R.-T.

(2012) Appl Microbiol Biotechnol 95: 661-669

  • DOI: 10.1007/s00253-011-3791-4
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • Cellulase 12A from Thermotoga maritima (TmCel12A) is a hyperthermostable β-1,4-endoglucanase. We recently determined the crystal structures of TmCel12A and its complexes with oligosaccharides. Here, by using site-directed mutagenesis, the role played ...

    Cellulase 12A from Thermotoga maritima (TmCel12A) is a hyperthermostable β-1,4-endoglucanase. We recently determined the crystal structures of TmCel12A and its complexes with oligosaccharides. Here, by using site-directed mutagenesis, the role played by Arg60 and Tyr61 in a unique surface loop of TmCel12A was investigated. The results are consistent with the previously observed hydrogen bonding and stacking interactions between these two residues and the substrate. Interestingly, the mutant Y61G had the highest activity when compared with the wild-type enzyme and the other mutants. It also shows a wider range of working temperatures than does the wild type, along with retention of the hyperthermostability. The k (cat) and K (m) values of Y61G are both higher than those of the wild type. In conjunction with the crystal structure of Y61G-substrate complex, the kinetic data suggest that the higher endoglucanase activity is probably due to facile dissociation of the cleaved sugar moiety at the reducing end. Additional crystallographic analyses indicate that the insertion and deletion mutations at the Tyr61 site did not affect the overall protein structure, but local perturbations might diminish the substrate-binding strength. It is likely that the catalytic efficiency of TmCel12A is a subtle balance between substrate binding and product release. The activity enhancement by the single mutation of Y61G provides a good example of engineered enzyme for industrial application.


    Organizational Affiliation

    Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Endo-1,4-beta-glucanaseA, B, C, D, E, F, G, H265Thermotoga maritimaMutation(s): 1 
Gene Names: celA
EC: 3.2.1.4
Find proteins for Q60032 (Thermotoga maritima)
Explore Q60032 
Go to UniProtKB:  Q60032
Protein Feature View
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  • Reference Sequence
Oligosaccharides
Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation
beta-D-glucopyranose-(1-4)-beta-D-glucopyranose
I, J, K, L, M, N, O, P
2 N/A
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.189 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.91α = 90
b = 124.039β = 107.06
c = 127.556γ = 90
Software Package:
Software NamePurpose
Blu-Icedata collection
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-07-11
    Type: Initial release
  • Version 1.1: 2013-07-17
    Changes: Database references
  • Version 1.2: 2017-11-22
    Changes: Refinement description
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Database references, Derived calculations, Non-polymer description, Structure summary