1JLR

STRUCTURE OF THE URACIL PHOSPHORIBOSYLTRANSFERASE GTP COMPLEX 2 MUTANT C128V


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.45 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.184 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

The structural mechanism of GTP stabilized oligomerization and catalytic activation of the Toxoplasma gondii uracil phosphoribosyltransferase.

Schumacher, M.A.Bashor, C.J.Song, M.H.Otsu, K.Zhu, S.Parry, R.J.Ullman, B.Brennan, R.G.

(2002) Proc.Natl.Acad.Sci.USA 99: 78-83

  • DOI: 10.1073/pnas.012399599
  • Primary Citation of Related Structures:  1JLS

  • PubMed Abstract: 
  • Uracil phosphoribosyltransferase (UPRT) is a member of a large family of salvage and biosynthetic enzymes, the phosphoribosyltransferases, and catalyzes the transfer of ribose 5-phosphate from alpha-d-5-phosphoribosyl-1-pyrophosphate (PRPP) to the N1 ...

    Uracil phosphoribosyltransferase (UPRT) is a member of a large family of salvage and biosynthetic enzymes, the phosphoribosyltransferases, and catalyzes the transfer of ribose 5-phosphate from alpha-d-5-phosphoribosyl-1-pyrophosphate (PRPP) to the N1 nitrogen of uracil. The UPRT from the opportunistic pathogen Toxoplasma gondii represents a promising target for rational drug design, because it can create intracellular, lethal nucleotides from subversive substrates. However, the development of such compounds requires a detailed understanding of the catalytic mechanism. Toward this end we determined the crystal structure of the T. gondii UPRT bound to uracil and cPRPP, a nonhydrolyzable PRPP analogue, to 2.5-A resolution. The structure suggests that the catalytic mechanism is substrate-assisted, and a tetramer would be the more active oligomeric form of the enzyme. Subsequent biochemical studies revealed that GTP binding, which has been suggested to play a role in catalysis by other UPRTs, causes a 6-fold activation of the T. gondii enzyme and strikingly stabilizes the tetramer form. The basis for stabilization was revealed in the 2.45-A resolution structure of the UPRT-GTP complex, whereby residues from three subunits contributed to GTP binding. Thus, our studies reveal an allosteric mechanism involving nucleotide stabilization of a more active, higher order oligomer. Such regulation of UPRT could play a role in the balance of purine and pyrimidine nucleotide pools in the cell.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Oregon Health and Science University, 3181 Southwest Sam Jackson Park Road, Portland, OR 97201-3098, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Uracil Phosphoribosyltransferase
A, B, D, C
243Toxoplasma gondiiGene Names: uprt
EC: 2.4.2.9
Find proteins for Q26998 (Toxoplasma gondii)
Go to UniProtKB:  Q26998
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4

Download SDF File 
Download CCD File 
A, B, C, D
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
GTP
Query on GTP

Download SDF File 
Download CCD File 
A, B, C, D
GUANOSINE-5'-TRIPHOSPHATE
C10 H16 N5 O14 P3
XKMLYUALXHKNFT-UUOKFMHZSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
GTPKd: 465000 nM BINDINGMOAD
GTPKd: 465000 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.45 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.184 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 60.600α = 90.00
b = 141.800β = 115.00
c = 71.400γ = 90.00
Software Package:
Software NamePurpose
bioteXdata scaling
CNSrefinement
CNSphasing
bioteXdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-01-10
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-04
    Type: Refinement description