3H2W

Structure of A. acidocaldarius cellulase CelA in complex with cellobiose


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.66 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.196 

Starting Model: experimental
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This is version 2.1 of the entry. See complete history


Literature

Crystal structures of A. acidocaldarius endoglucanase Cel9A in complex with Cello-oligosaccharides: strong -1 and -2 subsites mimic cellobiohydrolase activity

Eckert, K.Vigouroux, A.Lo Leggio, L.Morera, S.

(2009) J Mol Biol 394: 61-70

  • DOI: https://doi.org/10.1016/j.jmb.2009.08.060
  • Primary Citation of Related Structures:  
    3GZK, 3H2W, 3H3K

  • PubMed Abstract: 

    Alicyclobacillus acidocaldarius endoglucanase Cel9A (AaCel9A) is an inverting glycoside hydrolase with beta-1,4-glucanase activity on soluble polymeric substrates. Here, we report three X-ray structures of AaCel9A: a ligand-free structure at 1.8 A resolution and two complexes at 2.66 and 2.1 A resolution, respectively, with cellobiose obtained by co-crystallization and with cellotetraose obtained by the soaking method. AaCel9A forms an (alpha/alpha)(6)-barrel like other glycoside hydrolase family 9 enzymes. When cellobiose is used as a ligand, three glucosyl binding subsites are occupied, including two on the glycone side, while with cellotetraose as a ligand, five subsites, including four on the glycone side, are occupied. A structural comparison showed no conformational rearrangement of AaCel9A upon ligand binding. The structural analysis demonstrates that of the four minus subsites identified, subsites -1 and -2 show the strongest interaction with bound glucose. In conjunction with the open active-site cleft of AaCel9A, this is able to reconcile the previously observed cleavage of short-chain oligosaccharides with cellobiose as main product with the endo mode of action on larger polysaccharides.


  • Organizational Affiliation

    Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cellulase537Alicyclobacillus acidocaldarius subsp. acidocaldariusMutation(s): 0 
Gene Names: celA
EC: 3.2.1.4
UniProt
Find proteins for Q9AJS0 (Alicyclobacillus acidocaldarius subsp. acidocaldarius)
Explore Q9AJS0 
Go to UniProtKB:  Q9AJS0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9AJS0
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
beta-D-glucopyranose-(1-4)-alpha-D-glucopyranose
B
2N/A
Glycosylation Resources
GlyTouCan:  G86802XL
GlyCosmos:  G86802XL
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.66 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.196 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 84.892α = 90
b = 129.398β = 90
c = 48.965γ = 90
Software Package:
Software NamePurpose
JDirectordata collection
PHASERphasing
REFMACrefinement
XDSdata reduction
XDSdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-10-13
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary
  • Version 2.1: 2023-11-01
    Changes: Data collection, Database references, Refinement description, Structure summary