1EQU

TYPE 1 17-BETA HYDROXYSTEROID DEHYDROGENASE EQUILIN COMPLEXED WITH NADP+


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.315 
  • R-Value Work: 0.182 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of the ternary complex of human 17beta-hydroxysteroid dehydrogenase type 1 with 3-hydroxyestra-1,3,5,7-tetraen-17-one (equilin) and NADP+.

Sawicki, M.W.Erman, M.Puranen, T.Vihko, P.Ghosh, D.

(1999) Proc.Natl.Acad.Sci.USA 96: 840-845


  • PubMed Abstract: 
  • Excess 17beta-estradiol (E2), the most potent of human estrogens, is known to act as a stimulus for the growth of breast tumors. Human estrogenic 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1), which catalyzes the reduction of inactive estr ...

    Excess 17beta-estradiol (E2), the most potent of human estrogens, is known to act as a stimulus for the growth of breast tumors. Human estrogenic 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1), which catalyzes the reduction of inactive estrone (E1) to the active 17beta-estradiol in breast tissues, is a key enzyme responsible for elevated levels of E2 in breast tumor tissues. We present here the structure of the ternary complex of 17beta-HSD1 with the cofactor NADP+ and 3-hydroxyestra-1,3,5,7-tetraen-17-one (equilin), an equine estrogen used in estrogen replacement therapy. The ternary complex has been crystallized with a homodimer, the active form of the enzyme, in the asymmetric unit. Structural and kinetic data presented here show that the 17beta-HSD1-catalyzed reduction of E1 to E2 in vitro is specifically inhibited by equilin. The crystal structure determined at 3.0-A resolution reveals that the equilin molecule is bound at the active site in a mode similar to the binding of substrate. The orientation of the 17-keto group with respect to the nicotinamide ring of NADP+ and catalytic residues Tyr-155 and Ser-142 is different from that of E2 in the 17beta-HSD1-E2 complex. The ligand and substrate-entry loop densities are well defined in one subunit. The substrate-entry loop adopts a closed conformation in this subunit. The result demonstrates that binding of equilin at the active site of 17beta-HSD1 is the basis for inhibition of E1-to-E2 reduction by this equine estrogen in vitro. One possible outcome of estrogen replacement therapy in vivo could be reduction of E2 levels in breast tissues and hence the reduced risk of estrogen-dependent breast cancer.


    Organizational Affiliation

    Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PROTEIN (ESTRADIOL 17 BETA-DEHYDROGENASE 1)
A, B
327Homo sapiensMutation(s): 0 
Gene Names: HSD17B1 (E17KSR, EDH17B1, EDH17B2, EDHB17, SDR28C1)
EC: 1.1.1.62
Find proteins for P14061 (Homo sapiens)
Go to Gene View: HSD17B1
Go to UniProtKB:  P14061
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAP
Query on NAP

Download SDF File 
Download CCD File 
A, B
NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE
2'-MONOPHOSPHOADENOSINE 5'-DIPHOSPHORIBOSE
C21 H28 N7 O17 P3
XJLXINKUBYWONI-NNYOXOHSSA-N
 Ligand Interaction
EQI
Query on EQI

Download SDF File 
Download CCD File 
A
EQUILIN
C18 H20 O2
WKRLQDKEXYKHJB-HFTRVMKXSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.315 
  • R-Value Work: 0.182 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 44.020α = 90.00
b = 114.160β = 90.00
c = 114.840γ = 90.00
Software Package:
Software NamePurpose
AMoREphasing
DENZOdata reduction
X-PLORrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-12-02
    Type: Initial release
  • Version 1.1: 2008-04-26
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance