Crystal structure of mutant E393Q of MtGlu5

Experimental Data Snapshot

  • Resolution: 1.93 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.158 
  • R-Value Observed: 0.160 

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Synergic action of an inserted carbohydrate-binding module in a glycoside hydrolase family 5 endoglucanase.

Ye, T.J.Huang, K.F.Ko, T.P.Wu, S.H.

(2022) Acta Crystallogr D Struct Biol 78: 633-646

  • DOI: https://doi.org/10.1107/S2059798322002601
  • Primary Citation of Related Structures:  
    7VT4, 7VT5, 7VT6, 7VT7, 7VT8

  • PubMed Abstract: 

    Most known cellulase-associated carbohydrate-binding modules (CBMs) are attached to the N- or C-terminus of the enzyme or are expressed separately and assembled into multi-enzyme complexes (for example to form cellulosomes), rather than being an insertion into the catalytic domain. Here, by solving the crystal structure, it is shown that MtGlu5 from Meiothermus taiwanensis WR-220, a GH5-family endo-β-1,4-glucanase (EC, has a bipartite architecture consisting of a Cel5A-like catalytic domain with a (β/α) 8 TIM-barrel fold and an inserted CBM29-like noncatalytic domain with a β-jelly-roll fold. Deletion of the CBM significantly reduced the catalytic efficiency of MtGlu5, as determined by isothermal titration calorimetry using inactive mutants of full-length and CBM-deleted MtGlu5 proteins. Conversely, insertion of the CBM from MtGlu5 into TmCel5A from Thermotoga maritima greatly enhanced the substrate affinity of TmCel5A. Bound sugars observed between two tryptophan side chains in the catalytic domains of active full-length and CBM-deleted MtGlu5 suggest an important stacking force. The synergistic action of the catalytic domain and CBM of MtGlu5 in binding to single-chain polysaccharides was visualized by substrate modeling, in which additional surface tryptophan residues were identified in a cross-domain groove. Subsequent site-specific mutagenesis results confirmed the pivotal role of several other tryptophan residues from both domains of MtGlu5 in substrate binding. These findings reveal a way to incorporate a CBM into the catalytic domain of an existing enzyme to make a robust cellulase.

  • Organizational Affiliation

    Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Endoglucanase H
A, B
468Meiothermus taiwanensis WR-220Mutation(s): 1 
Find proteins for A0A399DY85 (Meiothermus taiwanensis)
Explore A0A399DY85 
Go to UniProtKB:  A0A399DY85
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A399DY85
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
SO4 (Subject of Investigation/LOI)
Query on SO4

Download Ideal Coordinates CCD File 
F [auth A]
G [auth A]
H [auth A]
I [auth A]
J [auth A]
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
P [auth B],
Q [auth B],
R [auth B],
S [auth B],
T [auth B],
U [auth B]
O4 S
GOL (Subject of Investigation/LOI)
Query on GOL

Download Ideal Coordinates CCD File 
C [auth A]
D [auth A]
E [auth A]
M [auth B]
N [auth B]
C [auth A],
D [auth A],
E [auth A],
M [auth B],
N [auth B],
O [auth B]
C3 H8 O3
Experimental Data & Validation

Experimental Data

  • Resolution: 1.93 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.158 
  • R-Value Observed: 0.160 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 74.249α = 90
b = 114.35β = 103.235
c = 80.149γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Academia Sinica (Taiwan)Taiwan--

Revision History  (Full details and data files)

  • Version 1.0: 2022-09-07
    Type: Initial release
  • Version 1.1: 2023-11-29
    Changes: Data collection, Refinement description