scholarly journals Kinetic and Thermodynamic Characterization of Dihydrotestosterone-Induced Conformational Perturbations in Androgen Receptor Ligand-Binding Domain

2009 ◽  
Vol 23 (8) ◽  
pp. 1231-1241 ◽  
Author(s):  
Ravi Jasuja ◽  
Jagadish Ulloor ◽  
Christopher M. Yengo ◽  
Karen Choong ◽  
Andrei Y. Istomin ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Ligand Binding ◽  
Conformational Changes ◽  
Solvent Accessibility ◽  
Molten Globule ◽  
Binding Pocket ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Second Derivative ◽  
Ligand Binding Pocket

Abstract Ligand-induced conformational perturbations in androgen receptor (AR) are important in coactivator recruitment and transactivation. However, molecular rearrangements in AR ligand-binding domain (AR-LBD) associated with agonist binding and their kinetic and thermodynamic parameters are poorly understood. We used steady-state second-derivative absorption and emission spectroscopy, pressure and temperature perturbations, and 4,4′-bis-anilinonaphthalene 8-sulfonate (bis-ANS) partitioning to determine the kinetics and thermodynamics of the conformational changes in AR-LBD after dihydrotestosterone (DHT) binding. In presence of DHT, the second-derivative absorption spectrum showed a red shift and a change in peak-to-peak distance. Emission intensity increased upon DHT binding, and center of spectral mass was blue shifted, denoting conformational changes resulting in more hydrophobic environment for tyrosines and tryptophans within a more compact DHT-bound receptor. In pressure perturbation calorimetry, DHT-induced energetic stabilization increased the Gibbs free energy of unfolding to 8.4 ± 1.3 kcal/mol from 3.5 ± 1.6 kcal/mol. Bis-ANS partitioning studies revealed that upon DHT binding, AR-LBD underwent biphasic rearrangement with a high activation energy (13.4 kcal/mol). An initial, molten globule-like burst phase (k ∼30 sec−1) with greater solvent accessibility was followed by rearrangement (k ∼0.01 sec−1), leading to a more compact conformation than apo-AR-LBD. Molecular simulations demonstrated unique sensitivity of tyrosine and tryptophan residues during pressure unfolding with rearrangement of residues in the coactivator recruitment surfaces distant from the ligand-binding pocket. In conclusion, DHT binding leads to energetic stabilization of AR-LBD domain and substantial rearrangement of residues distant from the ligand-binding pocket. DHT binding to AR-LBD involves biphasic receptor rearrangement including population of a molten globule-like intermediate state.

scholarly journals SUN-LB138 Dynamic Structural Model of Testosterone Entry Into the Unliganded Androgen Receptor

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Irina Krylova ◽  
Fred J Schaufele ◽  
Christophe Guilbert
Keyword(s):  
Amino Acids ◽  
Androgen Receptor ◽  
Ligand Binding ◽  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Binding Pocket ◽  
Binding Domain ◽  
Receptor Ligand ◽  
Ligand Binding Pocket ◽  
Crystallographic Structures

Abstract Background: Crystallographic structures of nuclear receptor ligand binding domains provide a static model of a receptor stably wrapped around an internalized ligand. Understanding the dynamics of a receptor at different stages of ligand binding has been hampered by the paucity of crystal structures for unliganded nuclear receptors. Molecular dynamic models have been constructed for some nuclear receptors to fill that void. Methods: The molecular simulation docking program MORDOR (MOlecular Recognition with a Driven dynamics OptimizeR)(1) was used to study the structural dynamics of the androgen receptor ligand binding domain (AR LBD) modeled from the static structure of the AR LBD bound to testosterone (T) (PDB ID: 2AM9). The goals of the study were to understand a) the dynamic interaction of the T in its binding pocket, b) AR LBD structural flexibilities that permit T entry/exit from the binding pocket and c) a model of the unliganded AR LBD. Results: Modeling AR LBD structure flexibility over time revealed possible alternative dynamic structures, including those without ligand, overlaid against the canonical nuclear receptor structure. The model dynamically tracks the structural changes as a ligand enters into the ligand binding domain and nestles into the ligand binding pocket. The model predicted the appearance of alpha helices within the AR LBD that transiently fold/unfold during the ligand entry phases. Once in the pocket, the ligand itself remains very dynamic in a still flexible pocket. The model predicted also AR LBD amino acids that sequentially interact with the ligand during its dynamic entry into the AR LBD. Intriguingly, those AR amino acids include those mutated in castration-resistant prostate tumors that continue to grow during androgen suppression therapy. Functional studies showed those mutant ARs had a primary consequence of enhancing response to lower level T, and other androgens, consistent with their role in creating a higher affinity AR that can scavenge low-level androgens in an androgen-suppressed patient. Conclusions: The molecular model of T binding to the AR LBD suggests a degree of structural dynamism not evident in the crystallographic structures commonly associated with nuclear receptors. Some AR mutations activating prostate tumor growth may do so by impacting androgen entry/exit, rather than by altering androgen fit into the ligand binding pocket. Reference: (1) Guilbert C, James TL (2008) J Chem Inf Model. 2008 48(6): 1257-1268. doi: 10.1021/ci8000327

X-ray crystal structure analysis of elacestrant (RAD1901), a novel selective estrogen receptor degrader (SERD), bound to estrogen receptor alpha ligand binding domain.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e15647-e15647
Author(s):  
Sean W. Fanning ◽  
Geoffrey Greene ◽  
Maureen G. Conlan
Keyword(s):  
Breast Cancer ◽  
Crystal Structure ◽  
Estrogen Receptor ◽  
Ligand Binding ◽  
Binding Pocket ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Ligand Binding Pocket ◽  
X Ray ◽  
Helix 12

e15647 Background: Antiestrogens are a mainstay of treatment for estrogen receptor positive (ER+) breast cancer in both the adjuvant and the advanced/metastatic settings. Elacestrant is a mixed activity selective estrogen receptor (SER) alpha (ERα) antagonist, acting as a SER modulator (SERM) at low doses and a SER degrader (SERD) at high doses. It has shown activity in hormone sensitive wild type (WT) ERα and insensitive estrogen receptor gene 1 (ESR1) mutation-harboring (Y537S and D538G) ERα breast cancer, both in preclinical models and in clinical studies. It also possesses a unique pharmacology compared to other competitive ER antagonists in its ability to cross the blood brain barrier. Competitive ERα antagonists are typically comprised of a core that sits in the ligand binding pocket and an arm that manipulates the structure to achieve SERM or SERD activities. In these molecules, the arm is attached in the same position as the triphenylethylene core of tamoxifen. However, elacestrant possesses a novel site of attachment. As such, we hypothesized that elacestrant adopts an alternative binding orientation in the ERα ligand binding pocket to achieve its unique pharmaceutical profiles. Methods: X-ray crystallography was used to solve a co-crystal structure of elacestrant in complex with WT ERα ligand binding domain to 2Å. Results: Overall, elacestrant promotes the formation of a canonical ERα ligand binding domain antagonist conformation, whereby helix 12 (H12) is docked into the activating function-2 cleft. However, elacestrant adopts a novel vector in the ERα ligand binding pocket that places it in close proximity to helix 12. As a result, it forms a bifurcated hydrogen bond that is not observed in other competitive antiestrogens and samples a chemical space known to increase H12 mobility and induce SERD activity. This novel vector also places it near positions 537 and 538, the two most common sites of somatic mutation. Conclusions: The high-resolution x-ray crystal structure of elacestrant suggests that the unique binding mode it adopts enables novel pharmacology and positions it to achieve potency in the WT and activating somatic ERα mutated breast cancer setting.

Functional studies on the ligand-binding domain of Ultraspiracle from Drosophila melanogaster

2004 ◽  
Vol 385 (1) ◽  
pp. 21-30 ◽  
Author(s):  
S. Przibilla ◽  
W. W. Hitchcock ◽  
M. Szécsi ◽  
M. Grebe ◽  
J. Beatty ◽  
...  
Keyword(s):  
Dna Binding ◽  
Fusion Protein ◽  
Ligand Binding ◽  
Binding Pocket ◽  
Negative Influence ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Ecdysteroid Receptor ◽  
Ligand Binding Pocket ◽  
Helix 12

AbstractThe functional insect ecdysteroid receptor is comprised of the ecdysone receptor (EcR) and Ultraspiracle (USP). The ligand-binding domain (LBD) of USP was fused to the GAL4 DNA-binding domain (GAL4-DBD) and characterized by analyzing the effect of site-directed mutations in the LBD. Normal and mutant proteins were tested for ligand and DNA binding, dimerization, and their ability to induce gene expression. The presence of helix 12 proved to be essential for DNA binding and was necessary to confer efficient ecdysteroid binding to the heterodimer with the EcR (LBD), but did not influence dimerization. The antagonistic position of helix 12 is indispensible for interaction between the fusion protein and DNA, whereas hormone binding to the EcR (LBD) was only partially reduced if fixation of helix 12 was disturbed. The mutation of amino acids, which presumably bind to a fatty acid evoked a profound negative influence on transactivation ability, although enhanced transactivation potency and ligand binding to the ecdysteroid receptor was impaired to varying degrees by mutation of these residues. Mutations of one fatty acidbinding residue within the ligand-binding pocket, I323, however, evoked enhanced transactivation. The results confirmed that the LBD of Ultraspiracle modifies ecdysteroid receptor function through intermolecular interactions and demonstrated that the ligand-binding pocket of USP modifies the DNA-binding and transactivation abilities of the fusion protein.

scholarly journals Systematic and functional characterization of novel androgen receptor variants arising from alternative splicing in the ligand-binding domain

Oncogene ◽  
2016 ◽  
Vol 36 (10) ◽  
pp. 1440-1450 ◽  
Author(s):  
T Uo ◽  
H Dvinge ◽  
C C Sprenger ◽  
R K Bradley ◽  
P S Nelson ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Alternative Splicing ◽  
Ligand Binding ◽  
Functional Characterization ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Androgen Receptor Variants

The androgen receptor depends on ligand‐binding domain dimerization for transcriptional activation

EMBO Reports ◽  
2021 ◽  
Author(s):  
Sarah El Kharraz ◽  
Vanessa Dubois ◽  
Martin E Royen ◽  
Adriaan B Houtsmuller ◽  
Ekatarina Pavlova ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Ligand Binding ◽  
Transcriptional Activation ◽  
Binding Domain ◽  
Ligand Binding Domain

scholarly journals Attractant- and Disulfide-Induced Conformational Changes in the Ligand Binding Domain of the Chemotaxis Aspartate Receptor: A 19F NMR Study

Biochemistry ◽  
1994 ◽  
Vol 33 (20) ◽  
pp. 6100-6109 ◽  
Author(s):  
Mark A. Danielson ◽  
Hans-Peter Biemann ◽  
Daniel E. Koshland ◽  
Joseph J. Falke
Keyword(s):  
Ligand Binding ◽  
Conformational Changes ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
19F Nmr ◽  
Aspartate Receptor ◽  
Nmr Study

scholarly journals SAT-288 Successful Virilization of a PAIS Patient with a Missense Mutation In The Ligand-binding Domain Of The Androgen Receptor with Combined High-dose Testosterone and Aromatase Inhibitor

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
DANIELA MORAES ◽  
SORAHIA DOMENICE ◽  
Eduardo FERREIRA ◽  
NATHALIA GOMES ◽  
MARIA HELENA SIRCILI ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Ligand Binding ◽  
Aromatase Inhibitor ◽  
Missense Mutation ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
High Dose

scholarly journals Ligand Photo-Isomerization Triggers Conformational Changes in iGluR2 Ligand Binding Domain

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e92716 ◽  
Author(s):  
Tino Wolter ◽  
Thomas Steinbrecher ◽  
Dirk Trauner ◽  
Marcus Elstner
Keyword(s):  
Ligand Binding ◽  
Conformational Changes ◽  
Binding Domain ◽  
Ligand Binding Domain
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