7MGQ

AICAR transformylase/IMP cyclohydrolase (ATIC) is essential for de novo purine biosynthesis and infection by Cryptococcus neoformans


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.67 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.200 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

AICAR transformylase/IMP cyclohydrolase (ATIC) is essential for de novo purine biosynthesis and infection by Cryptococcus neoformans.

Wizrah, M.S.I.Chua, S.M.H.Luo, Z.Manik, M.K.Pan, M.Whyte, J.M.L.Robertson, A.A.B.Kappler, U.Kobe, B.Fraser, J.A.

(2022) J Biol Chem 298: 102453-102453

  • DOI: https://doi.org/10.1016/j.jbc.2022.102453
  • Primary Citation of Related Structures:  
    7MGQ

  • PubMed Abstract: 

    The fungal pathogen Cryptococcus neoformans is a leading cause of meningoencephalitis in the immunocompromised. As current antifungal treatments are toxic to the host, costly, limited in their efficacy, and associated with drug resistance, there is an urgent need to identify vulnerabilities in fungal physiology to accelerate antifungal discovery efforts. Rational drug design was pioneered in de novo purine biosynthesis as the end products of the pathway, ATP and GTP, are essential for replication, transcription, and energy metabolism, and the same rationale applies when considering the pathway as an antifungal target. Here, we describe the identification and characterization of C. neoformans 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase/5'-inosine monophosphate cyclohydrolase (ATIC), a bifunctional enzyme that catalyzes the final two enzymatic steps in the formation of the first purine base inosine monophosphate. We demonstrate that mutants lacking the ATIC-encoding ADE16 gene are adenine and histidine auxotrophs that are unable to establish an infection in a murine model of virulence. In addition, our assays employing recombinantly expressed and purified C. neoformans ATIC enzyme revealed K m values for its substrates AICAR and 5-formyl-AICAR are 8-fold and 20-fold higher, respectively, than in the human ortholog. Subsequently, we performed crystallographic studies that enabled the determination of the first fungal ATIC protein structure, revealing a key serine-to-tyrosine substitution in the active site, which has the potential to assist the design of fungus-specific inhibitors. Overall, our results validate ATIC as a promising antifungal drug target.


  • Organizational Affiliation

    Australian Infectious Diseases Research Centre, University of Queensland, St Lucia, Queensland, Australia; School of Chemistry & Molecular Biosciences, University of Queensland, St Lucia, Queensland, Australia.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase
A, B, C, D
605Cryptococcus neoformansMutation(s): 0 
Gene Names: C356_00722
EC: 2.1.2.3 (PDB Primary Data), 3.5.4.10 (PDB Primary Data)
UniProt
Find proteins for A0A225ZZG7 (Cryptococcus neoformans var. grubii c45)
Explore A0A225ZZG7 
Go to UniProtKB:  A0A225ZZG7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A225ZZG7
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.67 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.200 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.841α = 90
b = 115.867β = 96.183
c = 111.823γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
Aimlessdata scaling
PHASERphasing
PHENIXmodel building

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Health and Medical Research Council (NHMRC, Australia)Australia--

Revision History  (Full details and data files)

  • Version 1.0: 2022-04-20
    Type: Initial release
  • Version 1.1: 2022-11-02
    Changes: Database references
  • Version 1.2: 2023-10-18
    Changes: Data collection, Refinement description