Crystal structure of exo-inulinase from Aspergillus awamori complexed with fructose

Experimental Data Snapshot

  • Resolution: 1.87 Å
  • R-Value Free: 0.195 
  • R-Value Work: 0.149 
  • R-Value Observed: 0.151 

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Crystal structure of exo-inulinase from Aspergillus awamori: the enzyme fold and structural determinants of substrate recognition

Nagem, R.A.P.Rojas, A.L.Golubev, A.M.Korneeva, O.S.Eneyskaya, E.V.Kulminskaya, A.A.Neustroev, K.N.Polikarpov, I.

(2004) J Mol Biol 344: 471-480

  • DOI: https://doi.org/10.1016/j.jmb.2004.09.024
  • Primary Citation of Related Structures:  
    1Y4W, 1Y9G, 1Y9M

  • PubMed Abstract: 

    Exo-inulinases hydrolyze terminal, non-reducing 2,1-linked and 2,6-linked beta-d-fructofuranose residues in inulin, levan and sucrose releasing beta-d-fructose. We present the X-ray structure at 1.55A resolution of exo-inulinase from Aspergillus awamori, a member of glycoside hydrolase family 32, solved by single isomorphous replacement with the anomalous scattering method using the heavy-atom sites derived from a quick cryo-soaking technique. The tertiary structure of this enzyme folds into two domains: the N-terminal catalytic domain of an unusual five-bladed beta-propeller fold and the C-terminal domain folded into a beta-sandwich-like structure. Its structural architecture is very similar to that of another member of glycoside hydrolase family 32, invertase (beta-fructosidase) from Thermotoga maritima, determined recently by X-ray crystallography The exo-inulinase is a glycoprotein containing five N-linked oligosaccharides. Two crystal forms obtained under similar crystallization conditions differ by the degree of protein glycosylation. The X-ray structure of the enzyme:fructose complex, at a resolution of 1.87A, reveals two catalytically important residues: Asp41 and Glu241, a nucleophile and a catalytic acid/base, respectively. The distance between the side-chains of these residues is consistent with a double displacement mechanism of reaction. Asp189, which is part of the Arg-Asp-Pro motif, provides hydrogen bonds important for substrate recognition.

  • Organizational Affiliation

    Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense 400, CEP 13560-970, São Carlos, SP, Brazil.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
exo-inulinase518Aspergillus awamoriMutation(s): 0 
Find proteins for Q96TU3 (Aspergillus awamori)
Explore Q96TU3 
Go to UniProtKB:  Q96TU3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ96TU3
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G42666HT
GlyCosmos:  G42666HT
GlyGen:  G42666HT
Experimental Data & Validation

Experimental Data

  • Resolution: 1.87 Å
  • R-Value Free: 0.195 
  • R-Value Work: 0.149 
  • R-Value Observed: 0.151 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.904α = 90
b = 94.371β = 107.1
c = 67.617γ = 90
Software Package:
Software NamePurpose
MAR345data collection
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-12-21
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description
  • Version 1.4: 2017-12-20
    Changes: Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary