scholarly journals Cryo-EM structure of the benzodiazepine-sensitive α1β1γ2 heterotrimeric GABAA receptor in complex with GABA illuminates mechanism of receptor assembly and agonist binding

2018 ◽  
Author(s):  
Swastik Phulera ◽  
Hongtao Zhu ◽  
Jie Yu ◽  
Derek P. Claxton ◽  
Nate Yoder ◽  
...  
Keyword(s):  
Ion Channel ◽  
Rational Design ◽  
Neurological Diseases ◽  
Therapeutic Agents ◽  
Structural Studies ◽  
Agonist Binding ◽  
Mutant Forms ◽  
Receptor Assembly ◽  
Anticonvulsive Agents ◽  
Α1 Subunit

ABSTRACTFast inhibitory neurotransmission in the mammalian nervous system is largely mediated by GABAA receptors, chloride-selective members of the superfamily of pentameric Cys-loop receptors. Native GABAA receptors are heteromeric assemblies sensitive to many important drugs, from sedatives to anesthetics and anticonvulsive agents, with mutant forms of GABAA receptors implicated in multiple neurological diseases, including epilepsy. Despite the profound importance of heteromeric GABAA receptors in neuroscience and medicine, they have proven recalcitrant to structure determination. Here we present the structure of the triheteromeric α1β1γ2EM GABAA receptor in complex with GABA, determined by single particle cryo-EM at 3.1-3.8 Å resolution, elucidating the molecular principles of receptor assembly and agonist binding. Remarkable N-linked glycosylation on the α1 subunit occludes the extracellular vestibule of the ion channel and is poised to modulate receptor assembly and perhaps ion channel gating. Our work provides a pathway to structural studies of heteromeric GABAA receptors and a framework for the rational design of novel therapeutic agents.

scholarly journals Cryo-EM structure of the benzodiazepine-sensitive α1β1γ2S tri-heteromeric GABAA receptor in complex with GABA

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Swastik Phulera ◽  
Hongtao Zhu ◽  
Jie Yu ◽  
Derek P Claxton ◽  
Nate Yoder ◽  
...  
Keyword(s):  
Ion Channel ◽  
Gabaa Receptor ◽  
Gabaa Receptors ◽  
Rational Design ◽  
Neurological Diseases ◽  
Therapeutic Agents ◽  
Structural Studies ◽  
Mutant Forms ◽  
Receptor Assembly ◽  
Α1 Subunit

Fast inhibitory neurotransmission in the mammalian nervous system is largely mediated by GABAA receptors, chloride-selective members of the superfamily of pentameric Cys-loop receptors. Native GABAA receptors are heteromeric assemblies sensitive to many important drugs, from sedatives to anesthetics and anticonvulsant agents, with mutant forms of GABAA receptors implicated in multiple neurological diseases. Despite the profound importance of heteromeric GABAA receptors in neuroscience and medicine, they have proven recalcitrant to structure determination. Here we present the structure of a tri-heteromeric α1β1γ2SEM GABAA receptor in complex with GABA, determined by single particle cryo-EM at 3.1–3.8 Å resolution, elucidating molecular principles of receptor assembly and agonist binding. Remarkable N-linked glycosylation on the α1 subunit occludes the extracellular vestibule of the ion channel and is poised to modulate receptor assembly and perhaps ion channel gating. Our work provides a pathway to structural studies of heteromeric GABAA receptors and a framework for rational design of novel therapeutic agents.

scholarly journals Monoclonal Antibodies as Neurological Therapeutics

2021 ◽  
Vol 14 (2) ◽  
pp. 92
Author(s):  
Panagiotis Gklinos ◽  
Miranta Papadopoulou ◽  
Vid Stanulovic ◽  
Dimos D. Mitsikostas ◽  
Dimitrios Papadopoulos
Keyword(s):  
Monoclonal Antibodies ◽  
Molecular Mechanisms ◽  
Neurological Diseases ◽  
Therapeutic Agents ◽  
Medical Specialties ◽  
Specific Effects ◽  
Different Types ◽  
Neurological Conditions ◽  
Disease Pathways

Over the last 30 years the role of monoclonal antibodies in therapeutics has increased enormously, revolutionizing treatment in most medical specialties, including neurology. Monoclonal antibodies are key therapeutic agents for several neurological conditions with diverse pathophysiological mechanisms, including multiple sclerosis, migraines and neuromuscular disease. In addition, a great number of monoclonal antibodies against several targets are being investigated for many more neurological diseases, which reflects our advances in understanding the pathogenesis of these diseases. Untangling the molecular mechanisms of disease allows monoclonal antibodies to block disease pathways accurately and efficiently with exceptional target specificity, minimizing non-specific effects. On the other hand, accumulating experience shows that monoclonal antibodies may carry class-specific and target-associated risks. This article provides an overview of different types of monoclonal antibodies and their characteristics and reviews monoclonal antibodies currently in use or under development for neurological disease.

scholarly journals A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

2016 ◽  
Vol 12 ◽  
pp. 125-138 ◽  
Author(s):  
Steven C Zimmerman
Keyword(s):  
Small Molecules ◽  
Supramolecular Chemistry ◽  
Myotonic Dystrophy ◽  
Small Molecule ◽  
Early Life ◽  
Rational Design ◽  
Early Experience ◽  
Therapeutic Agents ◽  
Early Career ◽  
Molecular Tweezers

This review summarizes part of the author’s research in the area of supramolecular chemistry, beginning with his early life influences and early career efforts in molecular recognition, especially molecular tweezers. Although designed to complex DNA, these hosts proved more applicable to the field of host–guest chemistry. This early experience and interest in intercalation ultimately led to the current efforts to develop small molecule therapeutic agents for myotonic dystrophy using a rational design approach that heavily relies on principles of supramolecular chemistry. How this work was influenced by that of others in the field and the evolution of each area of research is highlighted with selected examples.

scholarly journals Cryo-EM structures of a lipid-sensitive pentameric ligand-gated ion channel embedded in a phosphatidylcholine-only bilayer

2020 ◽  
Vol 117 (3) ◽  
pp. 1788-1798 ◽  
Author(s):  
Pramod Kumar ◽  
Yuhang Wang ◽  
Zhening Zhang ◽  
Zhiyu Zhao ◽  
Gisela D. Cymes ◽  
...  
Keyword(s):  
Ion Channel ◽  
Binding Sites ◽  
Electric Organ ◽  
Structural Models ◽  
Erwinia Chrysanthemi ◽  
Structural Basis ◽  
Agonist Binding ◽  
Nicotinic Acetylcholine ◽  
Bacterial Homolog ◽  
Straightforward Interpretation

The lipid dependence of the nicotinic acetylcholine receptor from the Torpedo electric organ has long been recognized, and one of the most consistent experimental observations is that, when reconstituted in membranes formed by zwitterionic phospholipids alone, exposure to agonist fails to elicit ion-flux activity. More recently, it has been suggested that the bacterial homolog ELIC (Erwinia chrysanthemi ligand-gated ion channel) has a similar lipid sensitivity. As a first step toward the elucidation of the structural basis of this phenomenon, we solved the structures of ELIC embedded in palmitoyl-oleoyl-phosphatidylcholine- (POPC-) only nanodiscs in both the unliganded (4.1-Å resolution) and agonist-bound (3.3 Å) states using single-particle cryoelectron microscopy. Comparison of the two structural models revealed that the largest differences occur at the level of loop C—at the agonist-binding sites—and the loops at the interface between the extracellular and transmembrane domains (ECD and TMD, respectively). On the other hand, the transmembrane pore is occluded in a remarkably similar manner in both structures. A straightforward interpretation of these findings is that POPC-only membranes frustrate the ECD–TMD coupling in such a way that the “conformational wave” of liganded-receptor gating takes place in the ECD and the interfacial M2–M3 linker but fails to penetrate the membrane and propagate into the TMD. Furthermore, analysis of the structural models and molecular simulations suggested that the higher affinity for agonists characteristic of the open- and desensitized-channel conformations results, at least in part, from the tighter confinement of the ligand to its binding site; this limits the ligand’s fluctuations, and thus delays its escape into bulk solvent.

Structural elements involved in activation of the γ-aminobutyric acid type A (GABAA) receptor

2004 ◽  
Vol 32 (3) ◽  
pp. 540-546 ◽  
Author(s):  
T.L. Kash ◽  
J.R. Trudell ◽  
N.L. Harrison
Keyword(s):  
Ion Channels ◽  
Ion Channel ◽  
Binding Site ◽  
Type A ◽  
Aminobutyric Acid ◽  
Structural Elements ◽  
Agonist Binding ◽  
Acid Type ◽  
Gated Ion Channels ◽  
Ligand Gated Ion Channels

Ligand-gated ion channels function as rapid signal transducers, converting chemical signals (in the form of neurotransmitters) into electrical signals in the postsynaptic neuron. This is achieved by the recognition of neurotransmitter at its specific-binding sites, which then triggers the opening of an ion channel (‘gating’). For this to occur rapidly (<1 ms), there must be an efficient coupling between the agonist-binding site and the gate, located more than 30 Å (1 Å=0.1 nm) away. Whereas a great deal of progress has been made in elucidating the structure and function of both the agonist-binding site and the ion permeation pathway in ligand-gated ion channels, our knowledge of the coupling mechanism between these domains has been limited. In this review, we summarize recent studies of the agonist-binding site and the ion channel in the γ-aminobutyric acid type A receptor, and discuss those structural elements that may mediate coupling between them. We will also consider some possible molecular mechanisms of receptor activation.

scholarly journals Structural Studies of the Gating Mechanism in a Pentameric Ligand-Gated Ion Channel Containing Two Additional N-Terminal Periplasmic Domains

2019 ◽  
Vol 116 (3) ◽  
pp. 396a
Author(s):  
Marc H. Delarue ◽  
Haidai Hu ◽  
Rebecca J. Howard ◽  
Urska Rovsnik ◽  
Sirine Hlioui ◽  
...  
Keyword(s):  
Ion Channel ◽  
Structural Studies ◽  
Gating Mechanism

scholarly journals Use of Organosilicon Compounds towards the Rational Design of Antiparasitic and Antiviral Drugs

1995 ◽  
Vol 2 (3) ◽  
pp. 143-151 ◽  
Author(s):  
Gérard Déléris
Keyword(s):  
Reverse Transcriptase ◽  
Antisense Oligonucleotides ◽  
Rational Design ◽  
Chemical Properties ◽  
Therapeutic Agents ◽  
Main Group ◽  
Biologically Active ◽  
Hiv Reverse Transcriptase ◽  
Antiparasitic Drugs ◽  
High Level

One of the major problems met for the conception of antiviral or antiparasitic drugs is to reach a high level of selectivity towards the pathogenic agent versus the host. We shall describe two synthetic approaches where main group organometallics have been used towards this goal. A series of nucleoside sila-analogues was synthesized as potential therapeutic agents designed to inhibit HIV Reverse Transcriptase. In a second approach novel organosilicon derivatives have been synthesized as mimics of antisense oligonucleotides.Infectious agents, namely viruses or parasites, more or less use cellular machinery. Therefore therapeutic agents must interfere with biochemical mechanisms or possess high affinity towards specific molecular cellular components, to reach selectivity.We thought that main group organometallics could show many advantages for designing biologically active molecules in this field. They allow a high synthetic flexibility for the modulations of physico-chemical properties and they show a mechanistic behaviour which may be close to the one of several heteroelements present in living organisms such as sulfur or phosphorus.We tried to use this approach towards two directions involving the synthesis of organosilicon derivatives i.e:-the synthesis of organosilicon derivatives as inhibitors of HIV Reverse Transcriptase,-the synthesis of organosilicon precursors of modified antisense oligonucleotides.

scholarly journals Towards Rational Design of a Toxoid Vaccine against the Heat-Stable Toxin of Escherichia coli

2016 ◽  
Vol 84 (4) ◽  
pp. 1239-1249 ◽  
Author(s):  
Arne M. Taxt ◽  
Yuleima Diaz ◽  
Rein Aasland ◽  
John D. Clements ◽  
James P. Nataro ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rational Design ◽  
Diarrheal Disease ◽  
Cross Reactivity ◽  
Single Amino Acid ◽  
Minimal Risk ◽  
Content Type ◽  
Heat Stable ◽  
Low Toxicity ◽  
Mutant Forms

EnterotoxigenicEscherichia coli(ETEC) is an important cause of diarrheal disease and death in children <5 years old. ETEC strains that express the heat-stable toxin (ST), with or without the heat-labile toxin, are among the four most important diarrhea-causing pathogens. This makes ST an attractive target for an ETEC vaccine. An ST vaccine should be nontoxic and elicit an immune response that neutralizes native ST without cross-reacting with the human endogenous guanylate cyclase C receptor ligands. To identify variants of ST with no or low toxicity, we screened a library of all 361 possible single-amino-acid mutant forms of ST by using the T84 cell assay. Moreover, we identified mutant variants with intact epitopes by screening for the ability to bind neutralizing anti-ST antibodies. ST mutant forms with no or low toxicity and intact epitopes are termed toxoid candidates, and the top 30 candidates all had mutations of residues A14, N12, and L9. The identification of nontoxic variants of L9 strongly suggests that it is a novel receptor-interacting residue, in addition to the previously identified N12, P13, and A14 residues. The screens also allowed us to map the epitopes of three neutralizing monoclonal antibodies, one of which cross-reacts with the human ligand uroguanylin. The common dominant epitope residue for all non-cross-reacting antibodies was Y19. Our results suggest that it should be possible to rationally design ST toxoids that elicit neutralizing immune responses against ST with minimal risk of immunological cross-reactivity.

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