人間のアデノシンA (((2A)) 受容体のリガンド依存の活性化と無活性化
Jianing Li1, Amanda L Jonsson, Thijs Beuming
1Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute and Computation Institute, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, USA.
Journal of the American Chemical Society
|May 18, 2013
まとめ
Gタンパク質結合受容体 (GPCR) は,薬物の主要標的である. 分子シミュレーションにより,ヒトのアデノシンA2A受容体が検出されました.
科学分野:
- 分子生物学は分子生物学である.
- バイオフィジックス 生物物理学
- 薬理学 薬理学とは
背景:
- Gタンパク質結合受容体 (GPCR) は,細胞シグナル伝達における重要な膜タンパク質であり,主要な薬物標的である.
- リンガンド依存のGPCR活性化の理解は,薬剤開発に不可欠ですが,実験的に困難です.
- アデノシンA2A受容体 (AA2AR) は,様々な疾患において重要な意味を持つクラスAGPCRである.
研究 の 目的:
- 人間のアデノシンA2A受容体 (AA2AR) のリガンド依存活性化および無活性化の原子レベルのメカニズムを解明する.
- AA2ARの構成変異とリガンド相互作用に関与する主要な構造要素と残基を特定する.
- GPCRsを標的とした構造ベースの薬物設計のためのダイナミックな枠組みを提供すること.
主な方法:
- 膜環境におけるAA2ARの大規模な偏らない分子動力学シミュレーション.
- メタダイナミクスのシミュレーションで,コンフォメーションの景観と自由エネルギーの探索を図る.
- 異なる構造状態と協同的な構成変化の分析.
主要な成果:
- 原子レベルでAA2ARの異なる活性・無活性構造状態を観測した.
- レセプター活性化中に重要なトリプトファン残留物 (Trp246 ((6.48)) を含む協調型構成変異を特定しました.
- リガンド結合が活性状態と非活性状態の間の均衡を変化させるという定量的証拠を提供した.
- リンガンド結合ポケット内の3つの異なる領域を提案し,アゴニズム,アンタゴニズム,親和性,選択性に影響を与えた.
結論:
- この研究は,AA2ARの動的活性化/無活性化メカニズムに関する原子レベルの洞察を提供し,結晶構造データを補完しています.
- この発見は,リガンド結合がGPCRの活性と構成状態をどのように調節するかを明らかにしています.
- 特定されたリガンド結合ポケットの構造的特徴と動的特性は,より効果的で選択的なGPCR標的薬の設計を導くことができます.
関連する概念動画
Adrenergic Receptors: ɑ Subtype
Adrenoceptors are classified into α and ꞵ classes based on their potencies to catecholamine agonists. α-adrenoceptors show the following order of catecholamine potency:
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...
Adrenergic Receptors (Adrenoceptors): Classification
Adrenergic receptors, or adrenoceptors, respond to the autonomic neurotransmitter noradrenaline and other endogenous catecholamine agonists. They are classified into two main families, α and β, based on their pharmacological response and are further subdivided depending on their location, elicited response, and affinity to specific agonists or antagonists.
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
Adrenergic Receptors: β Subtype
β-adrenoceptors have varied sensitivities towards adrenaline, noradrenaline, and isoprenaline. The order of agonist potency is as follows:
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
Adrenergic Agonists: Chemistry and Structure-Activity Relationship
Adrenergic agonists' structure-activity relationship (SAR) determines their selectivity and efficacy. These agonists comprise a phenylethylamine moiety with an aromatic ring and an ethylamine side chain.
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...


