Crystal structuore of acylphosphatase from Pyrococcus horikoshii complexed with formate

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.174 
  • R-Value Work: 0.166 
  • R-Value Observed: 0.167 

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Crystal Structure of a Hyperthermophilic Archaeal Acylphosphatase from Pyrococcus Horikoshii-Structural Insights Into Enzymatic Catalysis, Thermostability, and Dimerization

Cheung, Y.Y.Lam, S.Y.Chu, W.K.Allen, M.D.Bycroft, M.Wong, K.B.

(2005) Biochemistry 44: 4601

  • DOI: https://doi.org/10.1021/bi047832k
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Acylphosphatases catalyze the hydrolysis of the carboxyl-phosphate bond in acyl phosphates. Although acylphosphatase-like sequences are found in all three domains of life, no structure of acylphosphatase has been reported for bacteria and archaea so far. Here, we report the characterization of enzymatic activities and crystal structure of an archaeal acylphosphatase. A putative acylphosphatase gene (PhAcP) was cloned from the genomic DNA of Pyrococcus horikoshii and was expressed in Escherichia coli. Enzymatic parameters of the recombinant PhAcP were measured using benzoyl phosphate as the substrate. Our data suggest that, while PhAcP is less efficient than other mammalian homologues at 25 degrees C, the thermophilic enzyme is fully active at the optimal growth temperature (98 degrees C) of P. horikoshii. PhAcP is extremely stable; its apparent melting temperature was 111.5 degrees C and free energy of unfolding at 25 degrees C was 54 kJ mol(-)(1). The 1.5 A crystal structure of PhAcP adopts an alpha/beta sandwich fold that is common to other acylphosphatases. PhAcP forms a dimer in the crystal structure via antiparallel association of strand 4. Structural comparison to mesophilic acylphosphatases reveals significant differences in the conformation of the L5 loop connecting strands 4 and 5. The extreme thermostability of PhAcP can be attributed to an extensive ion-pair network consisting of 13 charge residues on the beta sheet of the protein. The reduced catalytic efficiency of PhAcP at 25 degrees C may be due to a less flexible active-site residue, Arg20, which forms a salt bridge to the C-terminal carboxyl group. New insights into catalysis were gained by docking acetyl phosphate to the active site of PhAcP.

  • Organizational Affiliation

    Department of Biochemistry, The Chinese University of Hong Kong, Hong Kong, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
91Pyrococcus horikoshiiMutation(s): 0 
Find proteins for P84142 (Pyrococcus horikoshii (strain ATCC 700860 / DSM 12428 / JCM 9974 / NBRC 100139 / OT-3))
Explore P84142 
Go to UniProtKB:  P84142
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP84142
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.174 
  • R-Value Work: 0.166 
  • R-Value Observed: 0.167 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 85.336α = 90
b = 85.336β = 90
c = 75.65γ = 120
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-08-04
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-24
    Changes: Source and taxonomy
  • Version 1.4: 2019-05-08
    Changes: Data collection, Experimental preparation
  • Version 1.5: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description