2J0F

Structural basis for non-competitive product inhibition in human thymidine phosphorylase: implication for drug design


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.246 
  • R-Value Observed: 0.248 

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This is version 1.3 of the entry. See complete history


Literature

Structural Basis for Non-Competitive Product Inhibition in Human Thymidine Phosphorylase: Implications for Drug Design.

El Omari, K.Bronckaers, A.Liekens, S.Perez-Perez, M.Balzarini, J.Stammers, D.K.

(2006) Biochem J 399: 199

  • DOI: https://doi.org/10.1042/BJ20060513
  • Primary Citation of Related Structures:  
    2J0F

  • PubMed Abstract: 

    HTP (human thymidine phosphorylase), also known as PD-ECGF (platelet-derived endothelial cell growth factor) or gliostatin, has an important role in nucleoside metabolism. HTP is implicated in angiogenesis and apoptosis and therefore is a prime target for drug design, including antitumour therapies. An HTP structure in a closed conformation complexed with an inhibitor has previously been solved. Earlier kinetic studies revealed an ordered release of thymine followed by ribose phosphate and product inhibition by both ligands. We have determined the structure of HTP from crystals grown in the presence of thymidine, which, surprisingly, resulted in bound thymine with HTP in a closed dead-end complex. Thus thymine appears to be able to reassociate with HTP after its initial ordered release before ribose phosphate and induces the closed conformation, hence explaining the mechanism of non-competitive product inhibition. In the active site in one of the four HTP molecules within the crystal asymmetric unit, additional electron density is present. This density has not been previously seen in any pyrimidine nucleoside phosphorylase and it defines a subsite that may be exploitable in drug design. Finally, because our crystals did not require proteolysed HTP to grow, the structure reveals a loop (residues 406-415), disordered in the previous HTP structure. This loop extends across the active-site cleft and appears to stabilize the dimer interface and the closed conformation by hydrogen-bonding. The present study will assist in the design of HTP inhibitors that could lead to drugs for anti-angiogenesis as well as for the potentiation of other nucleoside drugs.


  • Organizational Affiliation

    Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
THYMIDINE PHOSPHORYLASE
A, B, C, D
482Homo sapiensMutation(s): 0 
EC: 2.4.2.4
UniProt & NIH Common Fund Data Resources
Find proteins for P19971 (Homo sapiens)
Explore P19971 
Go to UniProtKB:  P19971
PHAROS:  P19971
GTEx:  ENSG00000025708 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP19971
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.246 
  • R-Value Observed: 0.248 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 103.078α = 90
b = 76.087β = 98.61
c = 99.575γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling
MOLREPphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-10-11
    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: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description