直接观察和测量蛋白质中的平均量子甲基道频率,使用编辑的双电子电子共振EPR光谱
Thomas Schmidt1, Francesco Torricella1, G Marius Clore1
1Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA. thomas.schmidt@nih.gov.
概括
在蛋白质中的甲基道直接观察使用电子磁共振. 这项研究揭示了标记蛋白质中的甲基道化速率,表明其旋转屏障很高.
科学领域:
- 生物物理学的生物物理.
- 蛋白质动力学 蛋白质动力学
- 电子偏磁共振光谱学 电子偏磁共振光谱学
背景情况:
- 蛋白质表现出复杂的动态,包括甲基旋转,这对它们的功能至关重要.
- 在分子层面上理解这些动态需要先进的光谱技术.
- 甲基道化是一种量子力学现象,已经被理论化,但很难在蛋白质中直接观察.
研究的目的:
- 在蛋白质环境中直接观察和量化甲基道化,使用电子磁共振 (EPR).
- 为了研究蛋白质结构内的甲基组的旋转动力学.
- 建立一种测量生物宏分子中甲基道化速率的方法.
主要方法:
- 使用了一种专门设计的同位素标记模型蛋白 ({U[2H];[Leu-[13CH3]}).
- 采用双电子-电子共振 (DEER) 光谱与Tm编辑的实验.
- 在两个站点内嵌入了旋转标签 (R1p氧化物侧链),其中一个站点展示了不同的符合性.
主要成果:
- 在DEER衍生的距离分布中观察到的振荡,归因于甲基道旋回回声封膜调制.
- 量化确定了0.12 MHz的平均甲基道速率.
- 提供了第一个直接的EPR证据,证明了蛋白质中的甲基道化.
结论:
- 甲基道化是一种可测量的蛋白质现象,受旋转屏障的影响.
- 观察到的道化速率表明甲基组存在显著的旋转障碍.
- 这项工作为使用EPR研究生物系统中的蛋白质动力学和量子效应开辟了新的途径.
相关概念视频
Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
3.5K
Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling interactions can occur between the spins of the unpaired electron and any neighboring spin-active nuclei. This hyperfine coupling results in hyperfine splitting, where the EPR signal is split into multiplets. The signals split into 2nI + 1 peaks, where n is the number of equivalent nuclei and I is the nuclear spin. These splitting patterns provide...
3.5K
Electron Affinity
43.4K
The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion).
43.4K
Quantum Numbers
50.5K
It is said that the energy of an electron in an atom is quantized; that is, it can be equal only to certain specific values and can jump from one energy level to another but not transition smoothly or stay between these levels.
50.5K
Electron Carriers
91.9K
Electron carriers can be thought of as electron shuttles. These compounds can easily accept electrons (i.e., be reduced) or lose them (i.e., be oxidized). They play an essential role in energy production because cellular respiration is contingent on the flow of electrons.
Over the many stages of cellular respiration, glucose breaks down into carbon dioxide and water. Electron carriers pick up electrons lost by glucose in these reactions, temporarily storing and releasing them into the electron...
Over the many stages of cellular respiration, glucose breaks down into carbon dioxide and water. Electron carriers pick up electrons lost by glucose in these reactions, temporarily storing and releasing them into the electron...
91.9K
Electron Transport Chains
112.4K
The final stage of cellular respiration is oxidative phosphorylation that consists of two steps: the electron transport chain and chemiosmosis. The electron transport chain is a set of proteins found in the inner mitochondrial membrane in eukaryotic cells. Its primary function is to establish a proton gradient that can be used during chemiosmosis to produce ATP and generate electron carriers, such as NAD+ and FAD, that are used in glycolysis and the citric acid cycle.
The ETC is comprised of...
The ETC is comprised of...
112.4K
Electron Behavior
109.0K
Overview
Electrons are negatively charged subatomic particles that are attracted to an orbit around the positively-charged nucleus of an atom. They reside in locations that are associated with energy levels called shells and are further organized into sub-shells and orbitals within each shell.
Electrons Orbit the Nucleus
Electrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the...
Electrons are negatively charged subatomic particles that are attracted to an orbit around the positively-charged nucleus of an atom. They reside in locations that are associated with energy levels called shells and are further organized into sub-shells and orbitals within each shell.
Electrons Orbit the Nucleus
Electrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the...
109.0K


