1EX8

CRYSTAL STRUCTURE OF 6-HYDROXYMETHYL-7,8-DIHYDROPTERIN PYROPHOSPHOKINASE COMPLEXED WITH HP4A, THE TWO-SUBSTRATE-MIMICKING INHIBITOR


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.185 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Literature

Bisubstrate analogue inhibitors of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase: synthesis and biochemical and crystallographic studies.

Shi, G.Blaszczyk, J.Ji, X.Yan, H.

(2001) J Med Chem 44: 1364-1371

  • DOI: https://doi.org/10.1021/jm0004493
  • Primary Citation of Related Structures:  
    1EX8

  • PubMed Abstract: 

    6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) catalyzes the transfer of pyrophosphate from ATP to 6-hydroxymethyl-7,8-dihydropterin (HP), leading to the biosynthesis of folate cofactors. Like other enzymes in the folate pathway, HPPK is an ideal target for the development of antimicrobial agents because the enzyme is essential for microorganisms but is absent from human and animals. Three bisubstrate analogues have been synthesized for HPPK and characterized by biochemical and X-ray crystallographic analyses. All three bisubstrate analogues consist of a pterin, an adenosine moiety, and a link composed of 2-4 phosphoryl groups. P(1)-(6-Hydroxymethylpterin)-P(2)-(5'-adenosyl)diphosphate (HP(2)A, 5) shows little affinity and inhibitory activity for E. coli HPPK. P(1)-(6-Hydroxymethylpterin)-P(3)-(5'-adenosyl)triphosphate (HP(3)A, 6) shows moderate affinity and inhibitory activity with K(d) = 4.25 microM in the presence of Mg(2+) and IC(50) = 1.27 microM. P(1)-(6-Hydroxymethylpterin)-P(4)-(5'-adenosyl)tetraphosphate (HP(4)A, 7) shows the highest affinity and inhibitory activity with K(d) = 0.47 microM in the presence of Mg(2+) and IC(50) = 0.44 microM. The affinity of MgHP(4)A for HPPK is approximately 116 and 76 times higher than that of MgADP and 6-hydroxymethylpterin, respectively. The crystal structure of HPPK in complex with 7 (HPPK.MgHP(4)A) has been determined at 1.85 A resolution with a crystallographic R factor of 0.185. The crystal structure shows that 7 occupies both HP- and ATP-binding sites and induces significant conformational changes in HPPK. The biochemical and structural studies of the bisubstrate analogues indicate that the bisubstrate analogue approach can produce more potent inhibitors for HPPK and the minimum length of the link for a bisubstrate analogue is approximately 7 A.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
6-HYDROXYMETHYL-7,8-DIHYDROPTERIN PYROPHOSPHOKINASE158Escherichia coliMutation(s): 0 
EC: 2.7.6.3
UniProt
Find proteins for P26281 (Escherichia coli (strain K12))
Explore P26281 
Go to UniProtKB:  P26281
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP26281
Sequence Annotations
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  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
A4P PDBBind:  1EX8 Kd: 470 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.185 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 38.053α = 90
b = 61.857β = 90
c = 67.106γ = 90
Software Package:
Software NamePurpose
AMoREphasing
SHELXL-97refinement
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: 2001-05-01
    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: 2023-08-09
    Changes: Data collection, Database references, Derived calculations, Refinement description
  • Version 1.4: 2023-08-30
    Changes: Database references, Structure summary