关于G蛋白与激素结合的G蛋白结合受体的机制性见解
Hossein Batebi1,2, Guillermo Pérez-Hernández3, Sabrina N Rahman4
1Universität Leipzig, Medizinische Fakultät, Institut für Medizinische Physik und Biophysik, Leipzig, Germany.
Nature structural & molecular biology
|June 12, 2024
概括
G-蛋白结合受体 (GPCRs) 通过释放GDP来激活G蛋白. 分子动力学揭示了受体结合如何触发Gs蛋白的结构变化,促进GDP喷射和信号传输.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- G蛋白结合受体 (GPCR) 是关键的细胞表面受体,参与许多生理过程.
- GPCRs激活异构三基G蛋白,启动细胞内信号级联.
- 激活过程涉及在Gα子单元上将瓜二酸盐 (GDP) 与瓜三酸盐 (GTP) 交换,这是一个关键的监管步骤.
研究的目的:
- 研究Gs蛋白在与β2-上腺素受体 (β2AR) 合时发生的原子层结构重组.
- 为了阐明GDP从Gs蛋白释放的机制,G蛋白激活的速度限制步骤.
- 了解信号是如何从受体传输到G蛋白的.
主要方法:
- 关于β2AR-Gs·GDP复合物的分子动力学 (MD) 模拟.
- 分析结构变化,包括螺旋运动和域开放.
- 现场定向突变发生和功能测试,以验证模拟结果.
主要成果:
- 结合GPCR会在Gs蛋白中诱导长距离的全效应,降低GDP释放的能量障碍.
- 关键的结构事件包括α1-αF螺旋的开放,αG螺旋的位移和α-螺旋域的开放.
- 信号传播涉及到一个扩展的受体接口,包括一个氨酸丰富的图案在跨膜螺旋6.
结论:
- 这项研究提供了G蛋白激活的动态视图,超越了静态快照.
- 识别受体-G蛋白界面的特定结构元素和相互作用,对信号传导至关重要.
- 提供了关于G蛋白合特异性和信号效率的分子基础的见解.
相关概念视频
G-protein Coupled Receptors
118.2K
G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
118.2K
G Protein-coupled Receptors
11.8K
G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
11.8K
Activation and Inactivation of G Proteins
7.0K
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high...
7.0K
Transducer Mechanism: G Protein–Coupled Receptors
1.9K
G Protein–Coupled Receptors (GPCRs) are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to various stimuli. GPCRs regulate critical physiological pathways and are excellent drug targets for treating diseases such as diabetes, cancer, obesity, depression, or Alzheimer's. Nearly 35% of approved drugs implement their therapeutic effects by selectively interacting with specific GPCRs.
GPCRs are also called heptahelical,...
GPCRs are also called heptahelical,...
1.9K
GPCRs Regulate Adenylyl Cylase Activity
5.5K
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...
5.5K
The Two-State Receptor Model
1.9K
The two-state receptor model explains a drug's interaction with receptors, such as G protein-coupled receptors and ligand-gated ion channels, to induce or inhibit a biological response. When no natural ligands are present, a receptor exists in an equilibrium of inactive (Ri) and active (Ra) conformations. The inactive form does not produce a response, while the active form generates a basal effect known as constitutive activity.
The binding affinity of a drug determines its interaction with...
The binding affinity of a drug determines its interaction with...
1.9K


