1TC1

A 1.4 ANGSTROM CRYSTAL STRUCTURE FOR THE HYPOXANTHINE PHOSPHORIBOSYLTRANSFERASE OF TRYPANOSOMA CRUZI


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.41 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.193 

Starting Model: experimental
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This is version 1.5 of the entry. See complete history


Literature

A 1.4 A crystal structure for the hypoxanthine phosphoribosyltransferase of Trypanosoma cruzi.

Focia, P.J.Craig III, S.P.Nieves-Alicea, R.Fletterick, R.J.Eakin, A.E.

(1998) Biochemistry 37: 15066-15075

  • DOI: https://doi.org/10.1021/bi981052s
  • Primary Citation of Related Structures:  
    1TC1

  • PubMed Abstract: 

    The hypoxanthine phosphoribosyltransferase (HPRT) from Trypanosoma cruzi, etiologic agent of Chagas' disease, was cocrystallized with the inosine analogue Formycin B (FmB) and the structure determined to 1.4 A resolution. This is the highest resolution structure yet reported for a phosphoribosyltransferase (PRT), and the asymmetric unit of the crystal contains a dimer of closely associated, nearly identical subunits. A conserved nonproline cis peptide in one active-site loop exposes the main-chain nitrogen to the enzyme active site, while the adjacent lysine side chain interacts with the other subunit of the dimer, thereby providing a possible mechanism for communication between the subunits and their active sites. The three-dimensional coordinates for the invariant Ser103-Tyr104 dipeptide are reported here for the first time. These are the only highly conserved residues in a second active-site loop, termed the long flexible loop, which is predicted to close over the active site of HPRTs to protect a labile transition state [Eads et al. (1994) Cell 78, 325-334]. This structure represents a major step forward in efforts to design/discover potent selective inhibitors of the HPRT of T. cruzi.


  • Organizational Affiliation

    Laboratory of Molecular Parasitology & Drug Design, School of Pharmacy, University of North Carolina, Chapel Hill 27599-7360, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PROTEIN (HYPOXANTHINE PHOSPHORIBOSYLTRANSFERASE)
A, B
220Trypanosoma cruziMutation(s): 3 
EC: 2.4.2.8
UniProt
Find proteins for Q4DRC4 (Trypanosoma cruzi (strain CL Brener))
Explore Q4DRC4 
Go to UniProtKB:  Q4DRC4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ4DRC4
Sequence Annotations
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  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
FMB PDBBind:  1TC1 IC50: 2.00e+6 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.41 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.193 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 39.5α = 90
b = 94.09β = 94.75
c = 52.12γ = 90
Software Package:
Software NamePurpose
AMoREphasing
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-10-07
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-24
    Changes: Database references
  • Version 1.4: 2018-01-31
    Changes: Database references
  • Version 1.5: 2023-08-23
    Changes: Data collection, Database references, Derived calculations, Refinement description