4AEK

Structural and biochemical characterization of a novel Carbohydrate Binding Module of endoglucanase Cel5A from Eubacterium cellulosolvens


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.188 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Understanding How Non-Catalytic Carbohydrate Binding Modules Can Display Specificity for Xyloglucan.

Luis, A.S.Venditto, I.Prates, J.A.M.Ferrieira, L.M.A.Temple, M.J.Rogowski, A.Basle, A.Xue, J.Knox, J.P.Najmudin, S.Fontes, C.M.G.A.Gilbert, H.J.

(2013) J.Biol.Chem. 288: 4799

  • DOI: 10.1074/jbc.M112.432781
  • Primary Citation of Related Structures:  2YPJ, 4AEM, 4AFD, 4AFM, 4BA6

  • PubMed Abstract: 
  • Plant biomass is central to the carbon cycle and to environmentally sustainable industries exemplified by the biofuel sector. Plant cell wall degrading enzymes generally contain noncatalytic carbohydrate binding modules (CBMs) that fulfil a targeting ...

    Plant biomass is central to the carbon cycle and to environmentally sustainable industries exemplified by the biofuel sector. Plant cell wall degrading enzymes generally contain noncatalytic carbohydrate binding modules (CBMs) that fulfil a targeting function, which enhances catalysis. CBMs that bind β-glucan chains often display broad specificity recognizing β1,4-glucans (cellulose), β1,3-β1,4-mixed linked glucans and xyloglucan, a β1,4-glucan decorated with α1,6-xylose residues, by targeting structures common to the three polysaccharides. Thus, CBMs that recognize xyloglucan target the β1,4-glucan backbone and only accommodate the xylose decorations. Here we show that two closely related CBMs, CBM65A and CBM65B, derived from EcCel5A, a Eubacterium cellulosolvens endoglucanase, bind to a range of β-glucans but, uniquely, display significant preference for xyloglucan. The structures of the two CBMs reveal a β-sandwich fold. The ligand binding site comprises the β-sheet that forms the concave surface of the proteins. Binding to the backbone chains of β-glucans is mediated primarily by five aromatic residues that also make hydrophobic interactions with the xylose side chains of xyloglucan, conferring the distinctive specificity of the CBMs for the decorated polysaccharide. Significantly, and in contrast to other CBMs that recognize β-glucans, CBM65A utilizes different polar residues to bind cellulose and mixed linked glucans. Thus, Gln(106) is central to cellulose recognition, but is not required for binding to mixed linked glucans. This report reveals the mechanism by which β-glucan-specific CBMs can distinguish between linear and mixed linked glucans, and show how these CBMs can exploit an extensive hydrophobic platform to target the side chains of decorated β-glucans.


    Related Citations: 
    • Overproduction, Purification, Crystallization and Preliminary X-Ray Characterization of a Novel Carbohydrate-Binding Module of Endoglucanase Cel5A from Eubacterium Cellulosolvens.
      Luis, A.S.,Alves, V.D.,Romao, M.J.,Prates, J.A.M.,Fontes, C.M.G.A.,Najmudin, S.
      (2011) Acta Crystallogr.,Sect.F 67: 491


    Organizational Affiliation

    CIISA, Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ENDOGLUCANASE CEL5A
A
134Eubacterium cellulosolvensGene Names: cel5A
Find proteins for Q3LHN3 (Eubacterium cellulosolvens)
Go to UniProtKB:  Q3LHN3
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.188 
  • Space Group: P 61 2 2
Unit Cell:
Length (Å)Angle (°)
a = 47.859α = 90.00
b = 47.859β = 90.00
c = 191.598γ = 120.00
Software Package:
Software NamePurpose
SASphasing
iMOSFLMdata reduction
SCALAdata scaling
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-01-16
    Type: Initial release
  • Version 1.1: 2013-02-27
    Type: Database references