通过光能量转移动力学揭示的cytochrome C化球体的结构特征
Julia G Lyubovitsky1, Harry B Gray, Jay R Winkler
1Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA.
Journal of the American Chemical Society
|December 12, 2002
概括
阴离子在重新折叠过程中改变蛋白质结构. 高度的盐促进了紧的蛋白质状态,有助于研究蛋白质折叠和非原生蛋白质状态.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 生物物理学的生物物理.
背景情况:
- 非原蛋白状态对于细胞功能至关重要,例如膜转位和粉样蛋白形成.
- 了解蛋白质结构异质性是分类这些状态的关键.
研究的目的:
- 为了研究阴离子如何影响蛋白质在重新折叠过程中的结构平衡.
- 描述Saccharomyces cerevisiae iso-1 细胞染色体c的结构变化.
主要方法:
- 利用光能量转移 (FRET) 动力学来监测蛋白质折叠.
- 在不同的盐条件下分析了多结构的变化 (紧与延伸).
主要成果:
- 发现添加的离子会改变紧和扩展的多结构之间的平衡.
- 在高盐度 (>=700 mM) 时,所有多都采用了紧的外形.
- 在紧状态下,C端基-血分离的平均值接近原生蛋白 (25 Å).
结论:
- 阴离子在重新折叠期间调节蛋白质结构动态方面发挥着重要作用.
- 高度的盐稳定了紧的蛋白质结构,提供了对非原生蛋白质状态的见解.
相关概念视频
Anatomy of Chloroplasts
Green algae and plants, including green stems and unripe fruit, harbor chloroplasts—the vital organelles where photosynthesis takes place. In plants, the highest density of chloroplasts is found in the mesophyll cells of leaves.
Photosystem I
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
The Anatomy of Chloroplasts
Green algae and plants, including green stems and unripe fruit, harbor specialized organelles called chloroplasts to carry out photosynthesis. They coordinate both stages of photosynthesis — the light-dependent reactions and the light-independent reactions. The light-dependent reactions use sunlight to release oxygen and produce chemical energy in the form of ATP and NADPH, and the light-independent reactions capture CO2 and use ATP and NADPH to produce sugar.
Structure of Chloroplasts
A...
Structure of Chloroplasts
A...
The Antenna Complex
Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - the main site of photochemical reactions as well as in the antenna complex. Under average light conditions, the rate at which reaction center pigments absorb light is far below the electron transport chain's capacity. As a result, the reaction center alone cannot provide enough energy to drive photosynthesis. The photosynthetic efficiency can...
ATP Synthase: Structure
ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in response to the electrochemical gradient, producing ATP from ADP and inorganic phosphate. ATP synthase can also work in a reverse direction by hydrolyzing ATP and generating an electrochemical gradient. Different forms of ATP synthases have evolved special features to meet the specific demands of the cell. Based on their specific feature, ATP...
Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...


