PDBsum entry 1qku

Nuclear receptor

PDB id: 1qku

Contents

Protein chains

250 a.a. *

Ligands

EST ×3

Waters ×596

* Residue conservation analysis

PDB id:

1qku

Name:

Nuclear receptor

Title:

Wild type estrogen nuclear receptor ligand binding domain complexed with estradiol

Structure:

Estradiol receptor. Chain: a, b, c. Fragment: ligand binding domain. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Cellular_location: nucleus. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.

Biol. unit:

Dimer (from PDB file)

Resolution:

3.20Å R-factor: 0.216 R-free: 0.275

Authors:

M.Ruff,M.Gangloff,S.Eiler,S.Duclaud,J.M.Wurtz,D.Moras

Key ref:

M.Gangloff et al. (2001). Crystal structure of a mutant hERalpha ligand-binding domain reveals key structural features for the mechanism of partial agonism. J Biol Chem, 276, 15059-15065. PubMed id: 11278577 DOI: 10.1074/jbc.M009870200

Date:

05-Aug-99 Release date: 18-Aug-00

Protein chains

P03372  (ESR1_HUMAN) -  Estrogen receptor from Homo sapiens

Seq: 595 a.a.

Struc: 250 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1074/jbc.M009870200

J Biol Chem 276:15059-15065 (2001)

PubMed id: 11278577

Crystal structure of a mutant hERalpha ligand-binding domain reveals key structural features for the mechanism of partial agonism.

M.Gangloff, M.Ruff, S.Eiler, S.Duclaud, J.M.Wurtz, D.Moras.

ABSTRACT

The crystal structure of a triple cysteine to serine mutant ERalpha ligand-binding domain (LBD), complexed with estradiol, shows that despite the presence of a tightly bound agonist ligand, the protein exhibits an antagonist-like conformation, similar to that observed in raloxifen and 4-hydroxytamoxifen-bound structures. This mutated receptor binds estradiol with wild type affinity and displays transcriptional activity upon estradiol stimulation, but with limited potency (about 50%). This partial activity is efficiently repressed in antagonist competition assays. The comparison with available LBD structures reveals key features governing the positioning of helix H12 and highlights the importance of cysteine residues in promoting an active conformation. Furthermore the present study reveals a hydrogen bond network connecting ligand binding to protein trans conformation. These observations support a dynamic view of H12 positioning, where the control of the equilibrium between two stable locations determines the partial agonist character of a given ligand.

Selected figure(s)

Figure 3.
Fig. 3. Superposition of binding pockets of the wild type (yellow) and mutant (gray) structures. The estradiol A ring superposes perfectly in both structures, whereas the D-ring is slightly shifted.

Figure 5.
Fig. 5. a, effect of C417S mutation on H3. Superposition of wild type (yellow) and Cys Ser triple mutant (gray) emphasizing the shortening of H3 by one turn and the significant conformational change of the loop 1-3 are shown. b, effect of C530S mutation on H11. Superposition of wild type (yellow) and Cys Ser triple mutant (gray), showing the shortening of H11 on the mutant protein is shown. c, superposition of wild type (yellow) and triple mutant (gray) ER LBD structures near the mutated residues. The ligand is anchored by His^524 that interacts with the carboxyl group of Glu^419, a residue from L5-6. This glutamate contacts both the N-terminal end of H3 (Glu^339) and the C-terminal end of H11 (Lys^531). The hydrogen bond network connecting the estradiol O17, His^524 and Glu^419, Glu^339, Lys^531 in the wild type structure is shown. The effect of the C417S and C530S mutations are to shorten by one turn the N-terminal end of H3 and the C-terminal end of H11, respectively. This leads to the disruption of the hydrogen bond network. To confirm the relevance of this network, Glu^339, Glu^419, and Lys^531 were mutated in alanines and compared with Cys Ser mutant receptor in transactivation assays.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2001, 276, 15059-15065) copyright 2001.

Figures were selected by the author.