3EQM

Crystal structure of human placental aromatase cytochrome P450 in complex with androstenedione


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.215 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural basis for androgen specificity and oestrogen synthesis in human aromatase.

Ghosh, D.Griswold, J.Erman, M.Pangborn, W.

(2009) Nature 457: 219-223

  • DOI: 10.1038/nature07614
  • Primary Citation of Related Structures:  
    3EQM

  • PubMed Abstract: 
  • Aromatase cytochrome P450 is the only enzyme in vertebrates known to catalyse the biosynthesis of all oestrogens from androgens. Aromatase inhibitors therefore constitute a frontline therapy for oestrogen-dependent breast cancer. In a three-step proc ...

    Aromatase cytochrome P450 is the only enzyme in vertebrates known to catalyse the biosynthesis of all oestrogens from androgens. Aromatase inhibitors therefore constitute a frontline therapy for oestrogen-dependent breast cancer. In a three-step process, each step requiring 1 mol of O(2), 1 mol of NADPH, and coupling with its redox partner cytochrome P450 reductase, aromatase converts androstenedione, testosterone and 16alpha-hydroxytestosterone to oestrone, 17beta-oestradiol and 17beta,16alpha-oestriol, respectively. The first two steps are C19-methyl hydroxylation steps, and the third involves the aromatization of the steroid A-ring, unique to aromatase. Whereas most P450s are not highly substrate selective, it is the hallmark androgenic specificity that sets aromatase apart. The structure of this enzyme of the endoplasmic reticulum membrane has remained unknown for decades, hindering elucidation of the biochemical mechanism. Here we present the crystal structure of human placental aromatase, the only natural mammalian, full-length P450 and P450 in hormone biosynthetic pathways to be crystallized so far. Unlike the active sites of many microsomal P450s that metabolize drugs and xenobiotics, aromatase has an androgen-specific cleft that binds the androstenedione molecule snugly. Hydrophobic and polar residues exquisitely complement the steroid backbone. The locations of catalytically important residues shed light on the reaction mechanism. The relative juxtaposition of the hydrophobic amino-terminal region and the opening to the catalytic cleft shows why membrane anchoring is necessary for the lipophilic substrates to gain access to the active site. The molecular basis for the enzyme's androgenic specificity and unique catalytic mechanism can be used for developing next-generation aromatase inhibitors.


    Organizational Affiliation

    Structural Biology, Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, New York 14203, USA. ghosh@hwi.buffalo.edu



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Cytochrome P450 19A1A503Homo sapiensMutation(s): 0 
Gene Names: CYP19A1ARO1CYARCYP19
EC: 1.14.14.1 (PDB Primary Data), 1.14.14.14 (UniProt)
Find proteins for P11511 (Homo sapiens)
Explore P11511 
Go to UniProtKB:  P11511
NIH Common Fund Data Resources
PHAROS  P11511
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download CCD File 
A
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
ASD
Query on ASD

Download CCD File 
A
4-ANDROSTENE-3-17-DIONE
C19 H26 O2
AEMFNILZOJDQLW-QAGGRKNESA-N
 Ligand Interaction
PO4
Query on PO4

Download CCD File 
A
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
ASDIC50:  300   nM  BindingDB
ASDKi:  20   nM  BindingDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.215 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 140.208α = 90
b = 140.208β = 90
c = 119.266γ = 120
Software Package:
Software NamePurpose
HKL-3000data collection
AMoREphasing
REFMACrefinement
HKL-3000data reduction
HKL-3000data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

  • Deposited Date: 2008-10-01 
  • Released Date: 2008-12-23 
  • Deposition Author(s): Ghosh, D.

Revision History 

  • Version 1.0: 2008-12-23
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2012-03-21
    Changes: Database references