乙2上腺素受体的上腺素激活结构被一个工程纳米体稳定
Aaron M Ring1,2, Aashish Manglik1, Andrew C Kruse1
1Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
Nature
|September 24, 2013
概括
研究人员捕获了与上腺素结合的β-2上腺受体 (β2AR) 的活性状态. 这一突破揭示了G-蛋白合受体 (GPCRs) 尽管具有不同的连接体亲和力,但仍然保留了激活机制.
科学领域:
- 生物化学和结构生物学.
- 分子药理学分子药理学
- 膜蛋白结构和功能 膜蛋白结构和功能
背景情况:
- G蛋白结合受体 (GPCRs) 对人类生理学至关重要,但它们的激活机制尚不清楚.
- 捕获与原生低亲和度神经递质结合的活性状态GPCRs一直是一个重大挑战.
- 之前的结构研究依赖于高亲和度连接体或通过突变发生的受体稳定.
研究的目的:
- 确定由本地激动剂激活GPCR的结构基础.
- 为了可视化β-2上腺受体 (β2AR) 与其内源性激动剂上腺素结合的活性状态.
- 为了研究不同GPCR激动剂的保存性联体识别和激活模式.
主要方法:
- 使用定向进化来设计驼类抗体片段,以稳定β2AR的活性状态.
- 采用X射线晶体学,获得激活的β2AR的高分辨率结构.
- 确定了与三种不同的激动剂结合的β2AR的结构:BI167107,基基异二醇和上腺素.
主要成果:
- 获得了与三种激动剂结合的活态人类β2AR的晶体结构,其亲和度从100nM到80pM不等.
- 尽管激动剂的化学结构和亲缘关系不同,但观察到一种保留的连接体识别和激活模式.
- 与上腺素结合的β2AR结构在细胞外循环3和跨膜螺旋6.6中显示了特定的重组.
- 确定了两种保存的氨酸之间的以水为媒介的键是活性GPCR状态的潜在稳定剂.
结论:
- 工程抗体碎片可以成功稳定并使具有本地连接体的活性状态GPCRs的结构研究成为可能.
- β2AR表现出一种保存的激活机制,即使与像上腺素这样的低亲和力内源激动剂.
- 对β2AR激活的结构洞察力为了解相关的G蛋白结合受体和药物开发提供了基础.
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