跨膜螺旋之间的直接相互作用稳定了细胞P450 2B4和细胞B5氧化还原复合体
Bikash R Sahoo1, Ayyalusamy Ramamoorthy1
1Biophysics Program, Department of Chemistry, Macromolecular Science and Engineering, Biomedical Engineering, Michigan Neuroscience Institute, The University of Michigan, Ann Arbor, MI 48109-1055, USA.
Biophysical chemistry
|August 16, 2023
概括
细胞染色体P450 2B4 (CYP2B4) 和细胞染色体b5 (Cyt-b5) 在ER膜中形成一个复合体,由盐桥和疏水相互作用驱动. 这种复杂化增强了结构稳定性和结合亲和力,影响了药物代谢.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 膜蛋白相互作用 相互作用
背景情况:
- 细胞染色体P450 2B4 (CYP2B4) 的活性是由其氧化还原伙伴细胞染色体b5 (Cyt-b5) 调节的.
- 细胞内膜中的相互作用会影响CYP2B4和Cyt-b5的复杂化和催化活性.
- 之前的研究使用固态NMR确定了自由和复杂的跨膜域 (TMD) 的膜拓.
研究的目的:
- 在膜环境中阐明CYP2B4和Cyt-b5复合的分子基础.
- 了解跨膜相互作用如何影响CYP2B4酶活性和反应速率.
- 提供ER膜中全长CYP2B4-Cyt-b5复合物的高分辨率结构模型.
主要方法:
- 多微秒的分子动态模拟,以建模TM域的交叉角度复杂形成.
- 确定稳定相互作用,包括盐桥,氨酸拉链和pi堆叠.
- 使用MM/PBSA计算结合的自由能量,用于全长和截断的可溶域.
主要成果:
- CYP2B4和Cyt-b5的跨膜域形成一个通过盐桥 (E2-R128,R21-D104,K25-D104) 和疏水相互作用稳定的横角复合体.
- 在CYP2B4中的氨酸拉链残留物和pi堆叠相互作用有助于在ER膜中的TM-TM复合物的稳定.
- 模拟的螺旋倾斜与以前的固态NMR数据保持一致;TM-TM包装与可溶域相比增强了结构稳定性.
结论:
- 这项研究揭示了CYP2B4-Cyt-b5复合体在ER膜中形成的详细分子机制.
- 跨膜域复合体表现出明显更高的结合亲和力和结构稳定性,而不是截断的可溶域复合体.
- 对全长CYP2B4-Cyt-b5复合物的高分辨率结构和动态洞察力可以为调节CYP2B4药物代谢活性的策略提供信息.
更多相关视频
相关概念视频
Electron Transport Chain: Complex III and IV
7.6K
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...
7.6K
The Supercomplexes in the Crista Membrane
2.5K
The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through respiratory complexes I to V. These complexes have been widely studied for decades, and it has been proven that they form supramolecular structures called respiratory supercomplexes (SC). These higher-order complexes may be crucial in maintaining the biochemical structure and improving the physiological activity of the individual complexes while...
2.5K
Electron Transport Chain: Complex I and II
14.5K
The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
ROS generation is regulated and maintained at moderate levels necessary...
14.5K
Electron Transport Chains
99.5K
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...
99.5K
Drug Metabolism: Phase I Reactions
3.4K
A phase I reaction is a biochemical process that introduces a functionally reactive polar group to a substance. This transformation predominantly occurs in the liver, facilitated by the cytochrome P450 system of hemoproteins situated in the lipophilic endoplasmic reticulum of cells. The metabolite generated through this process can have varying polarities. If it is sufficiently polar, it can be easily excreted in the urine due to its water compatibility. However, if the metabolite is nonpolar,...
3.4K
Redox Reactions
41
Redox reactions are vital biochemical processes that underpin energy metabolism in cells. These reactions involve the transfer of electrons between molecules, occurring in tandem as oxidation and reduction. Oxidation refers to the loss of electrons, while reduction denotes their gain. This coupling ensures the seamless flow of electrons through metabolic pathways. For example, in bacterial metabolism, glucose undergoes oxidation to carbon dioxide, while oxygen is simultaneously reduced to...
41


