scholarly journals LRET Investigations of Conformational Changes in the Ligand Binding Domain of a Functional AMPA Receptor†

Biochemistry ◽  
2008 ◽  
Vol 47 (38) ◽  
pp. 10027-10032 ◽  
Author(s):  
Jennifer Gonzalez ◽  
Anu Rambhadran ◽  
Mei Du ◽  
Vasanthi Jayaraman
Biochemistry ◽  
1994 ◽  
Vol 33 (20) ◽  
pp. 6100-6109 ◽  
Author(s):  
Mark A. Danielson ◽  
Hans-Peter Biemann ◽  
Daniel E. Koshland ◽  
Joseph J. Falke

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e92716 ◽  
Author(s):  
Tino Wolter ◽  
Thomas Steinbrecher ◽  
Dirk Trauner ◽  
Marcus Elstner

2018 ◽  
Vol 114 (3) ◽  
pp. 125a
Author(s):  
Hiraku Oshima ◽  
Suyong Re ◽  
Masayoshi Sakakura ◽  
Hideo Takahashi ◽  
Yuji Sugita

2019 ◽  
Vol 116 (37) ◽  
pp. 18578-18583 ◽  
Author(s):  
Peter J. Fuller ◽  
Yi-Zhou Yao ◽  
Ruitao Jin ◽  
Sitong He ◽  
Beatriz Martín-Fernández ◽  
...  

The mineralocorticoid receptor (MR) is highly conserved across vertebrate evolution. In terrestrial vertebrates, the MR mediates sodium homeostasis by aldosterone and also acts as a receptor for cortisol. Although the MR is present in fish, they lack aldosterone. The MR binds progesterone and spironolactone as antagonists in human MR but as agonists in zebrafish MR. We have defined the molecular basis of these divergent responses using MR chimeras between the zebrafish and human MR coupled with reciprocal site-directed mutagenesis and molecular dynamic (MD) simulation based on the crystal structures of the MR ligand-binding domain. Substitution of a leucine by threonine in helix 8 of the ligand-binding domain of the zebrafish MR confers the antagonist response. This leucine is conserved across fish species, whereas threonine (serine in rodents) is conserved in terrestrial vertebrate MR. MD identified an interaction of the leucine in helix 8 with a highly conserved leucine in helix 1 that stabilizes the agonist conformation including the interaction between helices 3 and 5, an interaction which has previously been characterized. This switch in the MR coincides with the evolution of terrestrial vertebrates and of aldosterone synthesis. It was perhaps mandatory if the appearance of aldosterone as a specific mediator of the homeostatic salt retention was to be tolerated. The conformational changes also provide insights into the structural basis of agonism versus antagonism in steroid receptors with potential implications for drug design in this important therapeutic target.


2009 ◽  
Vol 23 (8) ◽  
pp. 1231-1241 ◽  
Author(s):  
Ravi Jasuja ◽  
Jagadish Ulloor ◽  
Christopher M. Yengo ◽  
Karen Choong ◽  
Andrei Y. Istomin ◽  
...  

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.


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