Carbohydrate binding module family29 complexed with glucohexaose

Experimental Data Snapshot

  • Resolution: 1.15 Å
  • R-Value Free: 0.156 
  • R-Value Work: 0.128 
  • R-Value Observed: 0.129 

Starting Model: experimental
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Promiscuity in Ligand-Binding: The Three-Dimensional Structure of a Piromyces Carbohydrate-Binding Module,Cbm29-2,in Complex with Cello- and Mannohexaose

Charnock, S.J.Bolam, D.Nurizzo, D.Szabo, L.Mckie, V.Gilbert, H.Davies, G.J.

(2002) Proc Natl Acad Sci U S A 99: 14077

  • DOI: https://doi.org/10.1073/pnas.212516199
  • Primary Citation of Related Structures:  
    1GWK, 1GWL, 1GWM

  • PubMed Abstract: 

    Carbohydrate-protein recognition is central to many biological processes. Enzymes that act on polysaccharide substrates frequently contain noncatalytic domains, "carbohydrate-binding modules" (CBMs), that target the enzyme to the appropriate substrate. CBMs that recognize specific plant structural polysaccharides are often able to accommodate both the variable backbone and the side-chain decorations of heterogeneous ligands. "CBM29" modules, derived from a noncatalytic component of the Piromyces equi cellulase/hemicellulase complex, provide an example of this selective yet flexible recognition. They discriminate strongly against some polysaccharides while remaining relatively promiscuous toward both beta-1,4-linked manno- and cello-oligosaccharides. This feature may reflect preferential, but flexible, targeting toward glucomannans in the plant cell wall. The three-dimensional structure of CBM29-2 and its complexes with cello- and mannohexaose reveal a beta-jelly-roll topology, with an extended binding groove on the concave surface. The orientation of the aromatic residues complements the conformation of the target sugar polymer while accommodation of both manno- and gluco-configured oligo- and polysaccharides is conferred by virtue of the plasticity of the direct interactions from their axial and equatorial 2-hydroxyls, respectively. Such flexible ligand recognition targets the anaerobic fungal complex to a range of different components in the plant cell wall and thus plays a pivotal role in the highly efficient degradation of this composite structure by the microbial eukaryote.

  • Organizational Affiliation

    Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW, United Kingdom.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
NON-CATALYTIC PROTEIN 1153Piromyces sp. 'equiMutation(s): 0 
Find proteins for Q9C171 (Piromyces equi)
Explore Q9C171 
Go to UniProtKB:  Q9C171
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9C171
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G25708EF
GlyCosmos:  G25708EF
GlyGen:  G25708EF
Experimental Data & Validation

Experimental Data

  • Resolution: 1.15 Å
  • R-Value Free: 0.156 
  • R-Value Work: 0.128 
  • R-Value Observed: 0.129 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 107.707α = 90
b = 42.858β = 105.4
c = 35.555γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-03-20
    Type: Initial release
  • Version 1.1: 2011-05-08
    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, Other, Structure summary
  • Version 2.1: 2024-05-01
    Changes: Data collection, Database references, Refinement description, Structure summary