在GTP水解上对Ha-Ras p21蛋白的构造变化的时间解析X射线晶体学研究
I Schlichting1, S C Almo, G Rapp
1Abteilung Biophysik, Max-Planck-Institut für Medizinische Forschung, Heidelberg, FRG.
Nature
|May 24, 1990
概括
研究了GTP水解后Ha-Ras p21中的结构变化. GTP水解引发了p21的结构变化,影响了与GTPase激活蛋白的相互作用.
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:
- 哈拉斯p21是一种关键的信号蛋白,参与细胞生长和分化.
- GTP 水解是调节Ras蛋白活性的一个关键步骤.
- 了解p21的形状变化对于破译其生物功能至关重要.
研究的目的:
- 在GTP水解过程中研究Ha-Ras p21的结构动力学.
- 阐明了p21形状变化的基础分子机制.
- 为了确定这些结构变化的触发因素.
主要方法:
- 哈拉斯p21的结晶与被关闭的GTP.
- 使用Laue衍射的p21.GTP复合结构的确定.
- 在GTP水解前后对结构差异的分析.
主要成果:
- 暂时的p21.GTP复合物的结构得到了解决.
- 在与GTPase激活蛋白在水解后相互作用的区域观察到显著的形状变化.
- 活动部位Mg2+离子的协调转移被确定为可能的触发因素.
结论:
- GTP水解诱导了哈拉斯的实质性结构重组 p21.
- 这些变化对于调节与GTPase激活蛋白的相互作用至关重要.
- 2+离子的协调状态在启动水解合的构造级联中起着关键作用.
相关概念视频
02:14GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
01:14Rab Proteins
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
02:38The Ras Gene
The Ras-gene-encoded proteins are regulators of signaling pathways controlling cell proliferation, differentiation, or cell survival. The Ras-gene family in humans constitutes three primary members—the HRas, NRas, and KRas. These genes code for four functionally distinct yet closely related proteins—the HRas, NRas, KRas4A, and KRas4B. The involvement of mutant Ras genes in human cancer was first discovered in 1982 and is among the most common causes of human tumorigenesis.
Ras is a superfamily...
Ras is a superfamily...
01:25Rab Cascades
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
01:24Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
01:22Activation and Inactivation of G Proteins
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 affinity and are together...