对Rac特定的GAP,β2-chimaerin的脂质激活的结构机制
Bertram Canagarajah1, Federico Coluccio Leskow, Jonathan Yew Seng Ho
1Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, US Department of Health and Human Services, Bethesda, MD 20892, USA.
Cell
|October 28, 2004
概括
通过结合糖醇,通过破坏抑制相互作用来激活β2-基马林. 这项结构研究揭示了脂结合如何解锁Rac GTPase激活蛋白,使Rac结合和酶激活成为可能.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 细胞信号传递 细胞信号传递
背景情况:
- 甲糖醇 (DAG) 是一种脂质的第二信使.
- DAG与标蛋白的C1域结合,诱导转移到细胞膜和全激活.
- 贝塔2-基马林是一种小GTPase Rac.的GTPase激活蛋白 (GAP).
研究的目的:
- 为了确定β2-基马林在其无活性构造中的晶体结构.
- 阐明贝塔2-基马林由二甲酸甘油和脂调节的基础分子机制.
主要方法:
- 在3.2 Å分辨率的X射线晶体学.
- 蛋白质-蛋白质和蛋白质-脂质相互作用的结构分析.
主要成果:
- 不活跃的β2-基马林结构揭示了阻断RacGAP活性位点的N端.
- C1域的脂质结合部位被多个蛋白质区域的相互作用所掩盖.
- 脂与C1域的结合导致这些抑制相互作用的解离.
结论:
- 对C1域的脂结合是启动β2-基马林激活的关键事件.
- 抑制元素的解离允许N端解锁活性部位,激活RacGAP活动.
- 这项工作为C1域含有蛋白质的全激活机制提供了结构性的见解.
相关概念视频
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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...


