The orthosteric agonist-binding pocket in the prototypic class B G-protein-coupled secretin receptor

2013 ◽  
Vol 41 (1) ◽  
pp. 154-158 ◽  
Author(s):  
Laurence J. Miller ◽  
Maoqing Dong
Keyword(s):  
G Protein ◽  
Fluorescence Analysis ◽  
Binding Pocket ◽  
Rational Development ◽  
Secretin Receptor ◽  
Natural Ligands ◽  
Class B ◽  
G Protein Coupled ◽  
Moderate Length ◽  
Activity Series

Class B GPCRs (G-protein-coupled receptors) share heptahelical topology and G-protein binding with other superfamily members, yet have unique structures and modes of activation. Natural ligands for these receptors are moderate-length peptides with C-terminal α-helices. NMR and crystal structures of the peptide-bound disulfide-bonded receptor N-terminal domains demonstrate that these helices occupy a conserved groove; however, the details of this interaction vary from one receptor to another. In this review, we focus on the prototypic secretin receptor and use extensive intrinsic photoaffinity labelling, structure–activity series, alanine-replacement mutagenesis and fluorescence analysis to define the molecular basis for this interaction. Additionally, experimental validation of predictions coming from in silico molecular modelling has provided a basis for enhancement of binding affinity. Such insights will be useful in the rational development of drugs acting at this important group of targets.

scholarly journals Insights into Nuclear G-Protein-Coupled Receptors as Therapeutic Targets in Non-Communicable Diseases

2021 ◽  
Vol 14 (5) ◽  
pp. 439
Author(s):  
Salomé Gonçalves-Monteiro ◽  
Rita Ribeiro-Oliveira ◽  
Maria Sofia Vieira-Rocha ◽  
Martin Vojtek ◽  
Joana B. Sousa ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
G Protein ◽  
Communicable Disease ◽  
G Protein Coupled Receptors ◽  
Metabotropic Glutamate ◽  
Secretin Receptor ◽  
Class B ◽  
Fungal Mating ◽  
Extracellular Stimuli ◽  
G Protein Coupled

G-protein-coupled receptors (GPCRs) comprise a large protein superfamily divided into six classes, rhodopsin-like (A), secretin receptor family (B), metabotropic glutamate (C), fungal mating pheromone receptors (D), cyclic AMP receptors (E) and frizzled (F). Until recently, GPCRs signaling was thought to emanate exclusively from the plasma membrane as a response to extracellular stimuli but several studies have challenged this view demonstrating that GPCRs can be present in intracellular localizations, including in the nuclei. A renewed interest in GPCR receptors’ superfamily emerged and intensive research occurred over recent decades, particularly regarding class A GPCRs, but some class B and C have also been explored. Nuclear GPCRs proved to be functional and capable of triggering identical and/or distinct signaling pathways associated with their counterparts on the cell surface bringing new insights into the relevance of nuclear GPCRs and highlighting the nucleus as an autonomous signaling organelle (triggered by GPCRs). Nuclear GPCRs are involved in physiological (namely cell proliferation, transcription, angiogenesis and survival) and disease processes (cancer, cardiovascular diseases, etc.). In this review we summarize emerging evidence on nuclear GPCRs expression/function (with some nuclear GPCRs evidencing atypical/disruptive signaling pathways) in non-communicable disease, thus, bringing nuclear GPCRs as targets to the forefront of debate.

Mechanochemical Activation of Class-B G-Protein-Coupled Receptor upon Peptide–Ligand Binding

Nano Letters ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 5575-5582 ◽  
Author(s):  
Cristina Lo Giudice ◽  
Haonan Zhang ◽  
Beili Wu ◽  
David Alsteens
Keyword(s):  
Ligand Binding ◽  
G Protein ◽  
Mechanochemical Activation ◽  
Peptide Ligand ◽  
G Protein Coupled Receptor ◽  
Class B ◽  
G Protein Coupled

Receptor Activity Modifying Proteins Have Limited Effects on the Class B G Protein-Coupled Receptor Calcitonin Receptor-Like Receptor Stalk

Biochemistry ◽  
2018 ◽  
Vol 57 (8) ◽  
pp. 1410-1422 ◽  
Author(s):  
Michael L. Garelja ◽  
Christina A. Walker ◽  
Andrew Siow ◽  
Sung H. Yang ◽  
Paul W.R. Harris ◽  
...  
Keyword(s):  
G Protein ◽  
Receptor Activity ◽  
Calcitonin Receptor ◽  
G Protein Coupled Receptor ◽  
Class B ◽  
Receptor Activity Modifying Proteins ◽  
G Protein Coupled

scholarly journals The Retinoid and Non-Retinoid Ligands of the Rod Visual G Protein-Coupled Receptor

2019 ◽  
Vol 20 (24) ◽  
pp. 6218 ◽  
Author(s):  
Joseph T. Ortega ◽  
Beata Jastrzebska
Keyword(s):  
Drug Discovery ◽  
G Protein ◽  
Binding Sites ◽  
Binding Pocket ◽  
Biologically Active ◽  
Surface Receptors ◽  
Beneficial Effects ◽  
Light Sensing ◽  
Potential Binding ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) play a predominant role in the drug discovery effort. These cell surface receptors are activated by a variety of specific ligands that bind to the orthosteric binding pocket located in the extracellular part of the receptor. In addition, the potential binding sites located on the surface of the receptor enable their allosteric modulation with critical consequences for their function and pharmacology. For decades, drug discovery focused on targeting the GPCR orthosteric binding sites. However, finding that GPCRs can be modulated allosterically opened a new venue for developing novel pharmacological modulators with higher specificity. Alternatively, focus on discovering of non-retinoid small molecules beneficial in retinopathies associated with mutations in rhodopsin is currently a fast-growing pharmacological field. In this review, we summarize the accumulated knowledge on retinoid ligands and non-retinoid modulators of the light-sensing GPCR, rhodopsin and their potential in combating the specific vision-related pathologies. Also, recent findings reporting the potential of biologically active compounds derived from natural products as potent rod opsin modulators with beneficial effects against degenerative diseases related to this receptor are highlighted here.

scholarly journals Mechanism of the G-protein mimetic nanobody binding to a muscarinic G-protein-coupled receptor

2018 ◽  
Vol 115 (12) ◽  
pp. 3036-3041 ◽  
Author(s):  
Yinglong Miao ◽  
J. Andrew McCammon
Keyword(s):  
Protein Binding ◽  
G Protein ◽  
Protein Interactions ◽  
Intracellular Signaling ◽  
Md Simulations ◽  
Binding Pocket ◽  
Signaling Proteins ◽  
Protein Protein Interactions ◽  
Intracellular Loops ◽  
G Protein Coupled

Protein–protein binding is key in cellular signaling processes. Molecular dynamics (MD) simulations of protein–protein binding, however, are challenging due to limited timescales. In particular, binding of the medically important G-protein-coupled receptors (GPCRs) with intracellular signaling proteins has not been simulated with MD to date. Here, we report a successful simulation of the binding of a G-protein mimetic nanobody to the M2 muscarinic GPCR using the robust Gaussian accelerated MD (GaMD) method. Through long-timescale GaMD simulations over 4,500 ns, the nanobody was observed to bind the receptor intracellular G-protein-coupling site, with a minimum rmsd of 2.48 Å in the nanobody core domain compared with the X-ray structure. Binding of the nanobody allosterically closed the orthosteric ligand-binding pocket, being consistent with the recent experimental finding. In the absence of nanobody binding, the receptor orthosteric pocket sampled open and fully open conformations. The GaMD simulations revealed two low-energy intermediate states during nanobody binding to the M2 receptor. The flexible receptor intracellular loops contribute remarkable electrostatic, polar, and hydrophobic residue interactions in recognition and binding of the nanobody. These simulations provided important insights into the mechanism of GPCR–nanobody binding and demonstrated the applicability of GaMD in modeling dynamic protein–protein interactions.

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