1AK5

INOSINE MONOPHOSPHATE DEHYDROGENASE (IMPDH) FROM TRITRICHOMONAS FOETUS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.218 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structure of Tritrichomonas foetus inosine-5'-monophosphate dehydrogenase and the enzyme-product complex.

Whitby, F.G.Luecke, H.Kuhn, P.Somoza, J.R.Huete-Perez, J.A.Phillips, J.D.Hill, C.P.Fletterick, R.J.Wang, C.C.

(1997) Biochemistry 36: 10666-10674

  • DOI: 10.1021/bi9708850

  • PubMed Abstract: 
  • Inosine-5'-monophosphate dehydrogenase (IMPDH) is an attractive drug target for the control of parasitic infections. The enzyme catalyzes the oxidation of inosine monophosphate (IMP) to xanthosine monophosphate (XMP), the committed step in de novo gu ...

    Inosine-5'-monophosphate dehydrogenase (IMPDH) is an attractive drug target for the control of parasitic infections. The enzyme catalyzes the oxidation of inosine monophosphate (IMP) to xanthosine monophosphate (XMP), the committed step in de novo guanosine monophosphate (GMP) biosynthesis. We have determined the crystal structures of IMPDH from the protozoan parasite Tritrichomonas foetus in the apo form at 2.3 A resolution and the enzyme-XMP complex at 2.6 A resolution. Each monomer of this tetrameric enzyme is comprised of two domains, the largest of which includes an eight-stranded parallel beta/alpha-barrel that contains the enzyme active site at the C termini of the barrel beta-strands. A second domain, comprised of residues 102-220, is disordered in the crystal. IMPDH is expected to be active as a tetramer, since the active site cavity is formed by strands from adjacent subunits. An intrasubunit disulfide bond, seen in the crystal structure, may stabilize the protein in a less active form, as high concentrations of reducing agent have been shown to increase enzyme activity. Disorder at the active site suggests that a high degree of flexibility may be inherent in the catalytic function of IMPDH. Unlike IMPDH from other species, the T. foetus enzyme has a single arginine that is largely responsible for coordinating the substrate phosphate in the active site. This structural uniqueness may facilitate structure-based identification and design of compounds that specifically inhibit the parasite enzyme.


    Organizational Affiliation

    Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, 94143-0446, USA. frankw@solitude.med.utah.edu




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
INOSINE-5'-MONOPHOSPHATE DEHYDROGENASE
A
503Tritrichomonas foetusGene Names: IMPDH
EC: 1.1.1.205
Find proteins for P50097 (Tritrichomonas foetus)
Go to UniProtKB:  P50097
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.218 
  • Space Group: P 4 3 2
Unit Cell:
Length (Å)Angle (°)
a = 157.250α = 90.00
b = 157.250β = 90.00
c = 157.250γ = 90.00
Software Package:
Software NamePurpose
PHASESphasing
DENZOdata reduction
X-PLORrefinement
ROTAVATA)data scaling
ROTAVATA/AGROVATAdata reduction
XTALVIEWrefinement
CCP4data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 1997-05-28 
  • Released Date: 1997-09-17 
  • Deposition Author(s): Whitby, F.G.

Revision History 

  • Version 1.0: 1997-09-17
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance