2X2N

X-ray structure of cyp51 from trypanosoma brucei in complex with posaconazole in two different conformations


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.195 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Structural Characterization of Cyp51 from Trypanosoma Cruzi and Trypanosoma Brucei Bound to the Antifungal Drugs Posaconazole and Fluconazole

Chen, C.-K.Leung, S.S.F.Guilbert, C.Jacobson, M.Mckerrow, J.H.Podust, L.M.

(2010) PLoS Negl Trop Dis 4: E651

  • DOI: https://doi.org/10.1371/journal.pntd.0000651
  • Primary Citation of Related Structures:  
    2WUZ, 2WV2, 2WX2, 2X2N

  • PubMed Abstract: 

    Chagas Disease is the leading cause of heart failure in Latin America. Current drug therapy is limited by issues of both efficacy and severe side effects. Trypansoma cruzi, the protozoan agent of Chagas Disease, is closely related to two other major global pathogens, Leishmania spp., responsible for leishmaniasis, and Trypansoma brucei, the causative agent of African Sleeping Sickness. Both T. cruzi and Leishmania parasites have an essential requirement for ergosterol, and are thus vulnerable to inhibitors of sterol 14alpha-demethylase (CYP51), which catalyzes the conversion of lanosterol to ergosterol. Clinically employed anti-fungal azoles inhibit ergosterol biosynthesis in fungi, and specific azoles are also effective against both Trypanosoma and Leishmania parasites. However, modification of azoles to enhance efficacy and circumvent potential drug resistance has been problematic for both parasitic and fungal infections due to the lack of structural insights into drug binding. We have determined the crystal structures for CYP51 from T. cruzi (resolutions of 2.35 A and 2.27 A), and from the related pathogen T. brucei (resolutions of 2.7 A and 2.6 A), co-crystallized with the antifungal drugs fluconazole and posaconazole. Remarkably, both drugs adopt multiple conformations when binding the target. The fluconazole 2,4-difluorophenyl ring flips 180 degrees depending on the H-bonding interactions with the BC-loop. The terminus of the long functional tail group of posaconazole is bound loosely in the mouth of the hydrophobic substrate binding tunnel, suggesting that the major contribution of the tail to drug efficacy is for pharmacokinetics rather than in interactions with the target. The structures provide new insights into binding of azoles to CYP51 and mechanisms of potential drug resistance. Our studies define in structural detail the CYP51 therapeutic target in T. cruzi, and offer a starting point for rationally designed anti-Chagasic drugs with improved efficacy and reduced toxicity.


  • Organizational Affiliation

    Department of Pharmaceutical Chemistry, University of California, San Francisco, California, United States of America.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
LANOSTEROL 14-ALPHA-DEMETHYLASE
A, B, C, D
475Trypanosoma bruceiMutation(s): 3 
EC: 1.14.13.70
UniProt
Find proteins for Q385E8 (Trypanosoma brucei brucei (strain 927/4 GUTat10.1))
Explore Q385E8 
Go to UniProtKB:  Q385E8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ385E8
Sequence Annotations
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  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
X2N BindingDB:  2X2N Kd: 18 (nM) from 1 assay(s)
IC50: min: 48, max: 880 (nM) from 2 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.195 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 199.892α = 90
b = 114.527β = 131.83
c = 138.087γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata 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: 2010-02-02
    Type: Initial release
  • Version 1.1: 2012-04-11
    Changes: Database references, Version format compliance
  • Version 1.2: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description