2HE8

Crystal structure of 17alpha-hydroxysteroid dehydrogenase in its apo-form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.198 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Crystal Structures of Mouse 17alpha-Hydroxysteroid Dehydrogenase (Apoenzyme and Enzyme-NADP(H) Binary Complex): Identification of Molecular Determinants Responsible for the Unique 17alpha-reductive Activity of this Enzyme.

Faucher, F.Pereira de Jesus-Tran, K.Cantin, L.Luu-The, V.Labrie, F.Breton, R.

(2006) J.Mol.Biol. 364: 747-763

  • DOI: 10.1016/j.jmb.2006.09.030
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Very recently, the mouse 17alpha-hydroxysteroid dehydrogenase (m17alpha-HSD), a member of the aldo-keto reductase (AKR) superfamily, has been characterized and identified as the unique enzyme able to catalyze efficiently and in a stereospecific manne ...

    Very recently, the mouse 17alpha-hydroxysteroid dehydrogenase (m17alpha-HSD), a member of the aldo-keto reductase (AKR) superfamily, has been characterized and identified as the unique enzyme able to catalyze efficiently and in a stereospecific manner the conversion of androstenedione (Delta4) into epitestosterone (epi-T), the 17alpha-epimer of testosterone. Indeed, the other AKR enzymes that significantly reduce keto groups situated at position C17 of the steroid nucleus, the human type 3 3alpha-HSD (h3alpha-HSD3), the human and mouse type 5 17beta-HSD, and the rabbit 20alpha-HSD, produce only 17beta-hydroxy derivatives, although they possess more than 70% amino acid identity with m17alpha-HSD. Structural comparisons of these highly homologous enzymes thus offer an excellent opportunity of identifying the molecular determinants responsible for their 17alpha/17beta-stereospecificity. Here, we report the crystal structure of the m17alpha-HSD enzyme in its apo-form (1.9 A resolution) as well as those of two different forms of this enzyme in binary complex with NADP(H) (2.9 A and 1.35 A resolution). Interestingly, one of these binary complex structures could represent a conformational intermediate between the apoenzyme and the active binary complex. These structures provide a complete picture of the NADP(H)-enzyme interactions involving the flexible loop B, which can adopt two different conformations upon cofactor binding. Structural comparison with binary complexes of other AKR1C enzymes has also revealed particularities of the interaction between m17alpha-HSD and NADP(H), which explain why it has been possible to crystallize this enzyme in its apo form. Close inspection of the m17alpha-HSD steroid-binding cavity formed upon cofactor binding leads us to hypothesize that the residue at position 24 is of paramount importance for the stereospecificity of the reduction reaction. Mutagenic studies have showed that the m17alpha-HSD(A24Y) mutant exhibited a completely reversed stereospecificity, producing testosterone only from Delta4, whereas the h3alpha-HSD3(Y24A) mutant acquires the capacity to metabolize Delta4 into epi-T.


    Organizational Affiliation

    Oncology and Molecular Endocrinology Research Center, Laval University Medical Center (CHUL) and Laval University, Qu├ębec (QC), Canada G1V 4G2.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Aldo-keto reductase family 1, member C21
A, B
323Mus musculusMutation(s): 0 
Gene Names: Akr1c21
EC: 1.1.1.-
Find proteins for Q91WR5 (Mus musculus)
Go to UniProtKB:  Q91WR5
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download SDF File 
Download CCD File 
A
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
GOL
Query on GOL

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Download CCD File 
A, B
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
BME
Query on BME

Download SDF File 
Download CCD File 
A, B
BETA-MERCAPTOETHANOL
C2 H6 O S
DGVVWUTYPXICAM-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.198 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 98.060α = 90.00
b = 94.950β = 90.00
c = 69.360γ = 90.00
Software Package:
Software NamePurpose
CNSphasing
CNSrefinement
PDB_EXTRACTdata extraction
XSCALEdata processing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-12-05
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance
  • Version 1.3: 2011-10-05
    Type: Derived calculations