PDBsum entry 2wab

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Hydrolase PDB id
Jmol PyMol
Protein chain
327 a.a. *
GOL ×6
IOD ×6
Waters ×376
* Residue conservation analysis
PDB id:
Name: Hydrolase
Title: Structure of an active site mutant of a family two carbohydrate esterase from clostridium thermocellum in complex with celluohexase
Structure: Endoglucanase e. Chain: a. Fragment: c terminal domain cel5c-ces2a, residues 485-814. Synonym: endo-1,4-beta-glucanase e, carbohydrate esterase, cellulase e, ege. Engineered: yes. Mutation: yes
Source: Clostridium thermocellum. Organism_taxid: 1515. Atcc: 27405. Expressed in: escherichia coli. Expression_system_taxid: 511693.
1.90Å     R-factor:   0.158     R-free:   0.203
Authors: C.Montainer,V.A.Money,V.M.R.Pires,J.E.Flint,B.A.Pinheiro, A.Goyal,J.A.M.Prates,A.Izumi,H.Stalbrand,K.Kolenova, E.Topakas,E.J.Dodson,D.N.Bolam,G.J.Davies,C.M.G.A.Fontes, H.J.Gilbert
Key ref: C.Montanier et al. (2009). The active site of a carbohydrate esterase displays divergent catalytic and noncatalytic binding functions. PLoS Biol, 7, e71. PubMed id: 19338387
04-Feb-09     Release date:   24-Mar-09    
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Protein chain
Pfam   ArchSchema ?
P10477  (GUNE_CLOTM) -  Endoglucanase E
814 a.a.
327 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 1 residue position (black cross)

 Enzyme reactions 
   Enzyme class 1: E.C.  - Acetylxylan esterase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: Deacetylation of xylans and xylo-oligosaccharides.
   Enzyme class 2: E.C.  - Cellulase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: Endohydrolysis of 1,4-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans.
Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.
 Gene Ontology (GO) functional annotation 
  GO annot!
  Biochemical function     hydrolase activity, acting on ester bonds     1 term  


PLoS Biol 7:e71 (2009)
PubMed id: 19338387  
The active site of a carbohydrate esterase displays divergent catalytic and noncatalytic binding functions.
C.Montanier, V.A.Money, V.M.Pires, J.E.Flint, B.A.Pinheiro, A.Goyal, J.A.Prates, A.Izumi, H.Stålbrand, C.Morland, A.Cartmell, K.Kolenova, E.Topakas, E.J.Dodson, D.N.Bolam, G.J.Davies, C.M.Fontes, H.J.Gilbert.
Multifunctional proteins, which play a critical role in many biological processes, have typically evolved through the recruitment of different domains that have the required functional diversity. Thus the different activities displayed by these proteins are mediated by spatially distinct domains, consistent with the specific chemical requirements of each activity. Indeed, current evolutionary theory argues that the colocalization of diverse activities within an enzyme is likely to be a rare event, because it would compromise the existing activity of the protein. In contrast to this view, a potential example of multifunctional recruitment into a single protein domain is provided by CtCel5C-CE2, which contains an N-terminal module that displays cellulase activity and a C-terminal module, CtCE2, which exhibits a noncatalytic cellulose-binding function but also shares sequence identity with the CE2 family of esterases. Here we show that, unlike other CE2 members, the CtCE2 domain displays divergent catalytic esterase and noncatalytic carbohydrate binding functions. Intriguingly, these diverse activities are housed within the same site on the protein. Thus, a critical component of the active site of CtCE2, the catalytic Ser-His dyad, in harness with inserted aromatic residues, confers noncatalytic binding to cellulose whilst the active site of the domain retains its esterase activity. CtCE2 catalyses deacetylation of noncellulosic plant structural polysaccharides to deprotect these substrates for attack by other enzymes. Yet it also acts as a cellulose-binding domain, which promotes the activity of the appended cellulase on recalcitrant substrates. The CE2 family encapsulates the requirement for multiple activities by biocatalysts that attack challenging macromolecular substrates, including the grafting of a second, powerful and discrete noncatalytic binding functionality into the active site of an enzyme. This article provides a rare example of "gene sharing," where the introduction of a second functionality into the active site of an enzyme does not compromise the original activity of the biocatalyst.

Literature references that cite this PDB file's key reference

  PubMed id Reference
20373916 C.M.Fontes, and H.J.Gilbert (2010).
Cellulosomes: highly efficient nanomachines designed to deconstruct plant cell wall complex carbohydrates.
  Annu Rev Biochem, 79, 655-681.  
20659281 S.E.Marcus, A.W.Blake, T.A.Benians, K.J.Lee, C.Poyser, L.Donaldson, O.Leroux, A.Rogowski, H.L.Petersen, A.Boraston, H.J.Gilbert, W.G.Willats, and J.P.Knox (2010).
Restricted access of proteins to mannan polysaccharides in intact plant cell walls.
  Plant J, 64, 191-203.  
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