Sulfolobus solfataricus adenine phosphoribosyltransferase

Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.286 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.231 

Starting Models: experimental
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Adenine Phosphoribosyltransferase from Sulfolobus solfataricus Is an Enzyme with Unusual Kinetic Properties and a Crystal Structure that Suggests It Evolved from a 6-Oxopurine Phosphoribosyltransferase.

Jensen, K.F.Hansen, M.R.Jensen, K.S.Christoffersen, S.Poulsen, J.C.Mlgaard, A.Kadziola, A.

(2015) Biochemistry 54: 2323-2334

  • DOI: https://doi.org/10.1021/bi501334m
  • Primary Citation of Related Structures:  
    4TRB, 4TRC, 4TS5, 4TS7

  • PubMed Abstract: 

    The adenine phosphoribosyltransferase (APRTase) encoded by the open reading frame SSO2342 of Sulfolobus solfataricus P2 was subjected to crystallographic, kinetic, and ligand binding analyses. The enzyme forms dimers in solution and in the crystals, and binds one molecule of the reactants 5-phosphoribosyl-α-1-pyrophosphate (PRPP) and adenine or the product adenosine monophosphate (AMP) or the inhibitor adenosine diphosphate (ADP) in each active site. The individual subunit adopts an overall structure that resembles a 6-oxopurine phosphoribosyltransferase (PRTase) more than known APRTases implying that APRT functionality in Crenarchaeotae has its evolutionary origin in this family of PRTases. Only the N-terminal two-thirds of the polypeptide chain folds as a traditional type I PRTase with a five-stranded β-sheet surrounded by helices. The C-terminal third adopts an unusual three-helix bundle structure that together with the nucleobase-binding loop undergoes a conformational change upon binding of adenine and phosphate resulting in a slight contraction of the active site. The inhibitor ADP binds like the product AMP with both the α- and β-phosphates occupying the 5'-phosphoribosyl binding site. The enzyme shows activity over a wide pH range, and the kinetic and ligand binding properties depend on both pH and the presence/absence of phosphate in the buffers. A slow hydrolysis of PRPP to ribose 5-phosphate and pyrophosphate, catalyzed by the enzyme, may be facilitated by elements in the C-terminal three-helix bundle part of the protein.

  • Organizational Affiliation

    †University of Copenhagen, Department of Biology, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Purine phosphoribosyltransferase (GpT-1)
A, B
210Saccharolobus solfataricus P2Mutation(s): 0 
Gene Names: gpT-1SSO2342
EC: 2.4.2
Find proteins for Q97W95 (Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2))
Explore Q97W95 
Go to UniProtKB:  Q97W95
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ97W95
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.286 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.231 
  • Space Group: P 61
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 125.628α = 90
b = 125.628β = 90
c = 69.707γ = 120
Software Package:
Software NamePurpose

Structure Validation

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Entry History 

Deposition Data

  • Released Date: 2014-07-30 
  • Deposition Author(s): Kadziola, A.

Revision History  (Full details and data files)

  • Version 1.0: 2014-07-30
    Type: Initial release
  • Version 1.1: 2015-04-01
    Changes: Database references
  • Version 1.2: 2015-04-08
    Changes: Database references
  • Version 1.3: 2015-04-22
    Changes: Database references
  • Version 1.4: 2023-12-20
    Changes: Data collection, Database references, Refinement description