Key Amino Acids in the γ Subunit of the γ-Aminobutyric AcidA Receptor that Determine Ligand Binding and Modulation at the Benzodiazepine Site

1997 ◽  
Vol 52 (5) ◽  
pp. 874-881 ◽  
Author(s):  
Peter B. Wingrove ◽  
Sally A. Thompson ◽  
Keith A. Wafford ◽  
Paul J. Whiting
Keyword(s):  
Amino Acids ◽  
Ligand Binding ◽  
Γ Subunit ◽  
Benzodiazepine Site

Molecular Docking Analysis of Flavonoid Compounds with Matrix Metalloproteinase-8 for the Identification of Potential Effective Inhibitors

2020 ◽  
Vol 17 ◽  
Author(s):  
Amir Taherkhani ◽  
Athena Orangi ◽  
Shirin Moradkhani ◽  
Zahra Khamverdi
Keyword(s):  
Amino Acids ◽  
Molecular Docking ◽  
Amino Acid ◽  
Matrix Metalloproteinase ◽  
Ligand Binding ◽  
Chronic Inflammation ◽  
Cancer Progression ◽  
Dimensional Structure ◽  
Control Test ◽  
Therapeutic Procedures

Background: Matrix metalloproteinase-8 (MMP-8) participates in degradation of different types of collagens in the extracellular matrix and basement membrane. Up-regulation of the MMP-8 has been demonstrated in many of disorders including cancer development, tooth caries, periodontal/peri-implant soft and hard tissue degeneration, and acute/chronic inflammation. Therefore, MMP-8 has become an encouraging target for therapeutic procedures for scientists. We carried out molecular docking approach to study the binding affinity of 29 flavonoids, as drug candidates, with the MMP-8. Pharmacokinetic and toxicological properties of the compounds were also studied. Moreover, it was attempted to identify the most important amino acids participating in ligand binding based on degree of each of the amino acids in the ligand-amino acid interaction network for MMP-8. Methods: Three-dimensional structure of the protein was gained from the RCSB database (PDB ID: 4QKZ). AutoDock version 4.0 and Cytoscape 3.7.2 were used for molecular docking and network analysis, respectively. Notably, the inhibitor of the protein in the crystalline structure of the 4QKZ was considered as a control test. Pharmacokinetic and toxicological features of compounds were predicted using bioinformatic web tools. Post-docking analyses were performed using BIOVIA Discovery Studio Visualizer version 19.1.0.18287. Results and Discussions: According to results, 24 of the studied compounds considered to be top potential inhibitors for MMP-8 based on their salient estimated free energy of binding and inhibition constant as compared with the control test: Apigenin-7-glucoside, nicotiflorin, luteolin, glabridin, taxifolin, apigenin, licochalcone A, quercetin, isorhamnetin, myricetin, herbacetin, kaemferol, epicatechin, chrysin, amentoflavone, rutin, orientin, epiafzelechin, quercetin-3-rhamnoside, formononetin, isoliquiritigenin, vitexin, catechine, isoquercitrin. Moreover, His-197 was found to be the most important amino acid involved in the ligand binding for the enzyme. Conclusion: The results of the current study could be used in the prevention and therapeutic procedures of a number of disorders such as cancer progression and invasion, oral diseases, and acute/chronic inflammation. Although, in vitro and in vivo tests are inevitable in the future.

scholarly journals Identification by site-directed mutagenesis of amino acids contributing to ligand-binding specificity or signal transduction properties of the human FP prostanoid receptor

2003 ◽  
Vol 371 (2) ◽  
pp. 443-449 ◽  
Author(s):  
Frank NEUSCHÄFER-RUBE ◽  
Eva ENGEMAIER ◽  
Sina KOCH ◽  
Ulrike BÖER ◽  
Gerhard P. PÜSCHEL
Keyword(s):  
Amino Acids ◽  
Ligand Binding ◽  
G Protein ◽  
Transmembrane Domain ◽  
Sequence Similarity ◽  
Membrane Receptors ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Receptor Subtypes ◽  
Plasma Membrane Receptors

Prostanoid receptors belong to the class of heptahelical plasma membrane receptors. For the five prostanoids, eight receptor subtypes have been identified. They display an overall sequence similarity of roughly 30%. Based on sequence comparison, single amino acids in different subtypes of different species have previously been identified by site-directed mutagenesis or in hybrid receptors that appear to be essential for ligand binding or G-protein coupling. Based on this information, a series of mutants of the human FP receptor was generated and characterized in ligand-binding and second-messenger-formation studies. It was found that mutation of His-81 to Ala in transmembrane domain 2 and of Arg-291 to Leu in transmembrane domain 7, which are putative interaction partners for the prostanoid's carboxyl group, abolished ligand binding. Mutants in which Ser-263 in transmembrane domain 6 or Asp-300 in transmembrane domain 7 had been replaced by Ala or Gln, respectively, no longer discriminated between prostaglandins PGF2α and PGD2. Thus distortion of the topology of transmembrane domains 6 and 7 appears to interfere with the cyclopentane ring selectivity of the receptor. PGF2α-induced inositol formation was strongly reduced in the mutant Asp-300Gln, inferring a role for this residue in agonist-induced G-protein activation.

The Pharmacology of the Benzodiazepine Site of the GABA-A Receptor is Dependent on the Type of γ-Subunit Present

1995 ◽  
Vol 15 (1-4) ◽  
pp. 173-183 ◽  
Author(s):  
R. M. McKernan ◽  
K. Wafford ◽  
K. Quirk ◽  
K. L. Hadingham ◽  
E. A. Harley ◽  
...  
Keyword(s):  
Gaba A ◽  
Γ Subunit ◽  
Benzodiazepine Site

scholarly journals Unique functional properties of a member of the Fushi Tarazu-Factor 1 family from Schistosoma mansoni

2004 ◽  
Vol 382 (1) ◽  
pp. 337-351 ◽  
Author(s):  
Benjamin BERTIN ◽  
Souphatta SASORITH ◽  
Stéphanie CABY ◽  
Frédérik OGER ◽  
Jocelyne CORNETTE ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ligand Binding ◽  
Schistosoma Mansoni ◽  
Transcriptional Activity ◽  
Binding Pocket ◽  
Activation Function ◽  
Orphan Receptor ◽  
Fushi Tarazu ◽  
Dependent Activity ◽  
Arginine Residues

SmFtz-F1 (Schistosoma mansoni Fushi Tarazu-Factor 1) belongs to the Ftz-F1 subfamily of nuclear receptors, but displays marked structural differences compared with its mammalian homologues SF-1 (steroidogenic factor-1) or liver receptor homologue-1. These include a long F domain (104 amino acids), an unusually large hinge region (133 amino acids) and a poorly conserved E-domain. Here, using Gal4 constructs and a mammalian two-hybrid assay, we have characterized the roles of these specific regions both in the transcriptional activity of the receptor and in its interactions with cofactors. Our results have shown that, although the AF-2 (activation function-2) region is the major activation function of the receptor, both the F and D domains are essential for AF-2-dependent activity. Modelling of SmFtz-F1 LBD (ligand-binding domain) and structure-guided mutagenesis allowed us to show the important role of helix H1 in maintaining the structural conformation of the LBD, and suggested that its autonomous transactivation activity, also observed with SF-1, is fortuitous. This strategy also allowed us to study an eventual ligand-dependence for this orphan receptor, the predicted three-dimensional models suggesting that the SmFtz-F1 LBD contains a large and well-defined ligand-binding pocket sealed by two arginine residues orientated towards the interior of the cavity. Mutation of these two residues provoked a loss of transcriptional activity of the receptor, and strongly reduced its interaction with SRC1 (steroid receptor cofactor-1), suggesting a ligand-dependent activity for SmFtz-F1. Taken together, our results argue for original and specific functional activities for this platyhelminth nuclear receptor.

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

scholarly journals Evolutionary proteomics identifies amino acids essential for ligand-binding of the cytokinin receptor CHASE domain

2007 ◽  
Vol 7 (1) ◽  
pp. 62 ◽  
Author(s):  
Alexander Heyl ◽  
Klaas Wulfetange ◽  
Birgit Pils ◽  
Nicola Nielsen ◽  
Georgy A Romanov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ligand Binding ◽  
Cytokinin Receptor

scholarly journals Intron retention generates a novel isoform of the murine vitamin D receptor that acts in a dominant negative way on the vitamin D signaling pathway.

1996 ◽  
Vol 16 (7) ◽  
pp. 3393-3400 ◽  
Author(s):  
K Ebihara ◽  
Y Masuhiro ◽  
T Kitamoto ◽  
M Suzawa ◽  
Y Uematsu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Vitamin D ◽  
Ligand Binding ◽  
Signaling Pathway ◽  
Vitamin D Receptor ◽  
Target Genes ◽  
Stop Codon ◽  
Dominant Negative ◽  
Transient Expression Assay ◽  
Vitamin D Signaling

We identified and characterized a novel rat vitamin D receptor isoform (rVDR1), which retains intron 8 of the canonical VDR (rVDR0) during alternative splicing. In this isoform protein directed by the stop codon in this newly identified exon, a part of the ligand binding domain (86 amino acids) is truncated at the C-terminal end but contains 19 extra amino acids. The rVDR1 transcript was expressed at a level 1/15 to 1/20 of that of rVDR0 in the kidney and intestine in adult rats but not in embryos. The recombinant rVDR1 protein showed no ligand binding activity. Homo- and heterodimers of the recombinant rVDR0 and rVDR1 proteins bound to a consensus vitamin D response element (VDRE) but not to consensus response elements for thyroid hormone and retinoic acid. However, unlike rVDR0, rVDR1 did not form a heterodimeric complex with RXR on the VDRE. A transient expression assay showed that this isoform acted as a dominant negative receptor against rVDR0 transactivation. Interestingly, the dominant negative activities of rVDR1 differed among VDREs. Thus, the present study indicates that this new VDR isoform negatively modulates the vitamin D signaling pathway, through a particular set of target genes.

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