Crystal structure of a phosphorylated phytase from Aspergillus fumigatus, revealing the structural basis for its heat resilience and catalytic pathway

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.186 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.162 

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Crystal Structure of a Heat-resilient Phytase from Aspergillus fumigatus, Carrying a Phosphorylated Histidine

Xiang, T.Liu, Q.Deacon, A.M.Koshy, M.Kriksunov, I.A.Lei, X.G.Hao, Q.Thiel, D.J.

(2004) J Mol Biol 339: 437-445

  • DOI: https://doi.org/10.1016/j.jmb.2004.03.057
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    In order to understand the structural basis for the high thermostability of phytase from Aspergillus fumigatus, its crystal structure was determined at 1.5 A resolution. The overall fold resembles the structure of other phytase enzymes. Aspergillus niger phytase shares 66% sequence identity, however, it is much less heat-resistant. A superimposition of these two structures reveals some significant differences. In particular, substitutions with polar residues appear to remove repulsive ion pair interactions and instead form hydrogen bond interactions, which stabilize the enzyme; the formation of a C-terminal helical capping, induced by arginine residue substitutions also appears to be critical for the enzyme's ability to refold to its active form after denaturation at high temperature. The heat-resilient property of A.fumigatus phytase could be due to the improved stability of regions that are critical for the refolding of the protein; and a heat-resistant A.niger phytase may be achieved by mutating certain critical residues with the equivalent residues in A.fumigatus phytase. Six predicted N-glycosylation sites were observed to be glycosylated from the experimental electron density. Furthermore, the enzyme's catalytic residue His59 was found to be partly phosphorylated and thus showed a reaction intermediate, providing structural insight, which may help understand the catalytic mechanism of the acid phosphatase family. The trap of this catalytic intermediate confirms the two-step catalytic mechanism of the acid histidine phosphatase family.

  • Organizational Affiliation

    Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
phytase442Aspergillus fumigatusMutation(s): 0 
Find proteins for O00092 (Aspergillus fumigatus (strain ATCC MYA-4609 / CBS 101355 / FGSC A1100 / Af293))
Explore O00092 
Go to UniProtKB:  O00092
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO00092
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.186 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.162 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.34α = 90
b = 70.34β = 90
c = 186.673γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-06-01
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.3: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Data collection, Derived calculations, Structure summary