4AF0

Crystal structure of cryptococcal inosine monophosphate dehydrogenase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.175 

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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

De Novo GTP Biosynthesis is Critical for Virulence of the Fungal Pathogen Cryptococcus Neoformans

Morrow, C.A.Valkov, E.Stamp, A.Chow, E.W.L.Lee, I.R.Wronski, A.Williams, S.J.Hill, J.M.Djordjevic, J.T.Kappler, U.Kobe, B.Fraser, J.A.

(2012) PLoS Pathog 8: 2957

  • DOI: 10.1371/journal.ppat.1002957
  • Primary Citation of Related Structures:  
    4AF0

  • PubMed Abstract: 
  • We have investigated the potential of the GTP synthesis pathways as chemotherapeutic targets in the human pathogen Cryptococcus neoformans, a common cause of fatal fungal meningoencephalitis. We find that de novo GTP biosynthesis, but not the alternate salvage pathway, is critical to cryptococcal dissemination and survival in vivo ...

    We have investigated the potential of the GTP synthesis pathways as chemotherapeutic targets in the human pathogen Cryptococcus neoformans, a common cause of fatal fungal meningoencephalitis. We find that de novo GTP biosynthesis, but not the alternate salvage pathway, is critical to cryptococcal dissemination and survival in vivo. Loss of inosine monophosphate dehydrogenase (IMPDH) in the de novo pathway results in slow growth and virulence factor defects, while loss of the cognate phosphoribosyltransferase in the salvage pathway yielded no phenotypes. Further, the Cryptococcus species complex displays variable sensitivity to the IMPDH inhibitor mycophenolic acid, and we uncover a rare drug-resistant subtype of C. gattii that suggests an adaptive response to microbial IMPDH inhibitors in its environmental niche. We report the structural and functional characterization of IMPDH from Cryptococcus, revealing insights into the basis for drug resistance and suggesting strategies for the development of fungal-specific inhibitors. The crystal structure reveals the position of the IMPDH moveable flap and catalytic arginine in the open conformation for the first time, plus unique, exploitable differences in the highly conserved active site. Treatment with mycophenolic acid led to significantly increased survival times in a nematode model, validating de novo GTP biosynthesis as an antifungal target in Cryptococcus.


    Organizational Affiliation

    Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
INOSINE-5'-MONOPHOSPHATE DEHYDROGENASEA556Cryptococcus neoformans var. grubii H99Mutation(s): 0 
EC: 1.1.1.205
UniProt
Find proteins for E3P6S0 (Cryptococcus neoformans)
Explore E3P6S0 
Go to UniProtKB:  E3P6S0
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
INOSINE-5'-MONOPHOSPHATE DEHYDROGENASEB556Cryptococcus neoformans var. grubii H99Mutation(s): 0 
EC: 1.1.1.205
UniProt
Find proteins for E3P6S0 (Cryptococcus neoformans)
Explore E3P6S0 
Go to UniProtKB:  E3P6S0
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
MOA Binding MOAD:  4AF0 Ki: 198 (nM) from 1 assay(s)
BindingDB:  4AF0 IC50: 120 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.175 
  • Space Group: I 4
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 149.63α = 90
b = 149.63β = 90
c = 122.7γ = 90
Software Package:
Software NamePurpose
BUSTERrefinement
XDSdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-10-24
    Type: Initial release
  • Version 1.1: 2012-11-21
    Changes: Database references