Structure of human CYP11B1 in complex with fadrozole

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 

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Structure of human cortisol-producing cytochrome P450 11B1 bound to the breast cancer drug fadrozole provides insights for drug design.

Brixius-Anderko, S.Scott, E.E.

(2019) J Biol Chem 294: 453-460

  • DOI: https://doi.org/10.1074/jbc.RA118.006214
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Human cytochrome P450 11B1 (CYP11B1) is responsible for the final step generating the steroid hormone cortisol, which controls stress and immune responses and glucose homeostasis. CYP11B1 is a promising drug target to manage Cushing's disease, a disorder arising from excessive cortisol production. However, the design of selective inhibitors has been hampered because structural information for CYP11B1 is unavailable and the enzyme has high amino acid sequence identity (93%) to a closely related enzyme, the aldosterone-producing CYP11B2. Here we report the X-ray crystal structure of human CYP11B1 (at 2.1 Å resolution) in complex with fadrozole, a racemic compound normally used to treat breast cancer by inhibiting estrogen-producing CYP19A1. Comparison of fadrozole-bound CYP11B1 with fadrozole-bound CYP11B2 revealed that despite conservation of the active-site residues, the overall structures and active sites had structural rearrangements consistent with distinct protein functions and inhibition. Whereas fadrozole binds to both CYP11B enzymes by coordinating the heme iron, CYP11B2 binds to the R enantiomer of fadrozole, and CYP11B1 binds to the S enantiomer, each with distinct orientations and interactions. These results provide insights into the cross-reactivity of drugs across multiple steroidogenic cytochrome P450 enzymes, provide a structural basis for understanding human steroidogenesis, and pave the way for the design of more selective inhibitors of each human CYP11B enzyme.

  • Organizational Affiliation

    From the Departments of Medicinal Chemistry and.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cytochrome P450 11B1, mitochondrial
A, B
484Homo sapiensMutation(s): 0 
Gene Names: CYP11B1S11BH
Membrane Entity: Yes 
UniProt & NIH Common Fund Data Resources
Find proteins for P15538 (Homo sapiens)
Explore P15538 
Go to UniProtKB:  P15538
PHAROS:  P15538
GTEx:  ENSG00000160882 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP15538
Sequence Annotations
  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
JD7 Binding MOAD:  6M7X Kd: 9 (nM) from 1 assay(s)
BindingDB:  6M7X IC50: min: 40, max: 171 (nM) from 4 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 
  • Space Group: I 4
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 140.57α = 90
b = 140.57β = 90
c = 145.777γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2018-11-21
    Type: Initial release
  • Version 1.1: 2018-11-28
    Changes: Data collection, Database references
  • Version 1.2: 2019-01-23
    Changes: Data collection, Database references
  • Version 1.3: 2023-10-11
    Changes: Data collection, Database references, Derived calculations, Refinement description