1QK3

TOXOPLASMA GONDII HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE GMP COMPLEX


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.202 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Crystal Structures of the Toxoplasma Gondii Hypoxanthine-Guanine Phosphoribosyltransferase Gmp and -Imp Complexes: Comparison of Purine Binding Interactions with the Xmp Complex

Heroux, A.White, E.L.Ross, L.J.Borhani, D.W.

(1999) Biochemistry 38: 14485

  • Primary Citation of Related Structures:  
  • Also Cited By: 1QK5

  • PubMed Abstract: 
  • The crystal structures of the guanosine 5'-monophosphate (GMP) and inosine 5'-monophosphate (IMP) complexes of Toxoplasma gondii hypoxanthine-guanine phosphoribosyltransferase (HGPRT) have been determined at 1.65 and 1.90 A resolution. These complexe ...

    The crystal structures of the guanosine 5'-monophosphate (GMP) and inosine 5'-monophosphate (IMP) complexes of Toxoplasma gondii hypoxanthine-guanine phosphoribosyltransferase (HGPRT) have been determined at 1.65 and 1.90 A resolution. These complexes, which crystallize in space groups P2(1) (a = 65.45 A, b = 90.84 A, c = 80. 26 A, and beta = 92.53 degrees ) and P2(1)2(1)2(1) (a = 84.54 A, b = 102.44 A, and c = 108.83 A), each comprise a tetramer in the crystallographic asymmetric unit. All active sites in the tetramers are fully occupied by the nucleotide. Comparison of these structures with that of the xanthosine 5'-monophosphate (XMP)-pyrophosphate-Mg(2+) ternary complex reported in the following article [Héroux, A., et al. (1999) Biochemistry 38, 14495-14506] shows how T. gondii HGPRT is able to recognize guanine, hypoxanthine, and xanthine as substrates, and suggests why the human enzyme cannot use xanthine efficiently. Comparison with the apoenzyme reveals the structural changes that occur upon binding of purines and ribose 5'-phosphate to HGPRT. Two structural features important to the HGPRT mechanism, a previously unrecognized active site loop (loop III', residues 180-184) and an active site peptide bond (Leu78-Lys79) that adopts both the cis and the trans configurations, are presented.


    Related Citations: 
    • Crystal Structure of Toxoplasma Gondii Hypoxanthine-Guanine Phosphoribosyltransferase with Xmp, Pyrophosphate and Two Mg2+ Ions Bound: Insights Into the Catalytic Mechanism
      Heroux, A.,White, E.L.,Ross, L.J.,Davis, R.L.,Borhani, D.W.
      (1999) Biochemistry 38: 14495
    • Isolation and Sequencing of a Cdna Encoding the Hypoxanthine-Guanine Phosphoribosyltransferase from Toxoplasma Gondii
      Vasanthakumar, G.,Van Ginkel, S.,Parish, G.
      (1994) Gene 147: 153


    Organizational Affiliation

    Drug Discovery Division, Southern Research Institute, Birmingham, Alabama 35205, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE
A, B, C, D
233Toxoplasma gondiiMutation(s): 0 
Gene Names: HPRT
EC: 2.4.2.22, 2.4.2.8
Find proteins for Q26997 (Toxoplasma gondii)
Go to UniProtKB:  Q26997
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
5GP
Query on 5GP

Download SDF File 
Download CCD File 
A, B, C, D
GUANOSINE-5'-MONOPHOSPHATE
C10 H14 N5 O8 P
RQFCJASXJCIDSX-UUOKFMHZSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
5GPKd: 7100 nM BINDINGMOAD
5GPKd: 7100 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.202 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 65.453α = 90.00
b = 90.842β = 92.53
c = 80.256γ = 90.00
Software Package:
Software NamePurpose
AMoREphasing
SCALAdata scaling
MOSFLMdata reduction
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-10-17
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2019-03-06
    Type: Data collection, Experimental preparation, Other