1L1Y

The Crystal Structure and Catalytic Mechanism of Cellobiohydrolase CelS, the Major Enzymatic Component of the Clostridium thermocellum cellulosome

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.191 

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This is version 2.0 of the entry. See complete history. 


Literature

The crystal structure and catalytic mechanism of cellobiohydrolase CelS, the major enzymatic component of the Clostridium thermocellum Cellulosome.

Guimaraes, B.G., Souchon, H., Lytle, B.L., David Wu, J.H., Alzari, P.M.

(2002) J Mol Biol 320: 587-596

  • DOI: 10.1016/s0022-2836(02)00497-7
  • Primary Citation of Related Structures:  
    1L1Y, 1L2A

  • PubMed Abstract: 

    • Cellobiohydrolase CelS plays an important role in the cellulosome, an active cellulase system produced by the thermophilic anaerobe Clostridium thermocellum. The structures of the catalytic domain of CelS in complex with substrate (cellohexaose) and product (cellobiose) were determined at 2 ...

    Cellobiohydrolase CelS plays an important role in the cellulosome, an active cellulase system produced by the thermophilic anaerobe Clostridium thermocellum. The structures of the catalytic domain of CelS in complex with substrate (cellohexaose) and product (cellobiose) were determined at 2.5 and 2.4 A resolution, respectively. The protein folds into an (alpha/alpha)(6) barrel with a tunnel-shaped substrate-binding region. The conformation of the loops defining the tunnel is intrinsically stable in the absence of substrate, suggesting a model to account for the processive mode of action of family 48 cellobiohydrolases. Structural comparisons with other (alpha/alpha)(6) barrel glycosidases indicate that CelS and endoglucanase CelA, a sequence-unrelated family 8 glycosidase with a groove-shaped substrate-binding region, use the same catalytic machinery to hydrolyze the glycosidic linkage, despite a low sequence similarity and a different endo/exo mode of action. A remarkable feature of the mechanism is the absence, from CelS, of a carboxylic group acting as the base catalyst. The nearly identical arrangement of substrate and functionally important residues in the two active sites strongly suggests an evolutionary relationship between the cellobiohydrolase and endoglucanase families, which can therefore be classified into a new clan of glycoside hydrolases.

    Organizational Affiliation: 

    Unité de Biochimie Structurale, CNRS URA 2185, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris cedex 15, France.



Macromolecules
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
cellobiohydrolase
A, B, C, D, E, F
A, B, C, D, E, F
678Acetivibrio thermocellusMutation(s): 0 
Gene Names: celS
EC: 3.2.1.4 (PDB Primary Data), 3.2.1.176 (UniProt)
UniProt
Find proteins for P0C2S5 (Acetivibrio thermocellus)
Explore P0C2S5 
Go to UniProtKB:  P0C2S5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0C2S5
Protein Feature View
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
beta-D-glucopyranose-(1-4)-beta-D-glucopyranose
G, H, I, J, K, L
G, H, I, J, K, L
2N/A Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G84824ZO
GlyCosmos:  G84824ZO
Biologically Interesting Molecules (External Reference) 1 Unique
Entity ID: 2
IDChainsNameType/Class2D Diagram3D Interactions
PRD_900005
Query on PRD_900005		G, H, I, J, K, Lbeta-cellobioseOligosaccharide / Metabolism Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.191 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 147.243α = 90
b = 207.204β = 90
c = 213.22γ = 90
Software Package:
Software NamePurpose
AMoREphasing
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-07-17
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary