在细菌硫酸盐脱酶中的分子内电子转移
Changjian Feng1, Ulrike Kappler, Gordon Tollin
1Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA.
Journal of the American Chemical Society
|December 3, 2003
概括
硫酸盐脱酶 (SDH) 通过其蛋白质介质表现出直接的分子内电子转移 (IET). 这与其他硫酸盐氧化酶形成鲜明对比,表明IET并不普遍依赖子单元运动或粘度.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 结构生物学 结构生物学
背景情况:
- 硫酸盐脱酶 (SDH) 是一种含有的酶,对硫酸盐氧化至关重要.
- 来自Starkeya小说中的SDH具有独特的alphabeta-heterodimeric结构,其Mo辅因子和c型heme具有不同的子单位.
- 酶中的分子内部电子转移 (IET) 机制对于它们的催化功能至关重要,并且可以受到蛋白质结构和环境的影响.
研究的目的:
- 研究Starkeya新型硫酸盐脱酶 (SDH) 中的分子内部电子转移 (IET) 的机制.
- 阐明蛋白质结构和环境因素对SDH中的IET动力学的作用.
- 将SDH的IET机制与动物硫酸盐氧化酶 (SO) 的IET机制进行比较.
主要方法:
- 利用闪光光电解来研究纯化SDH中的分子内部电子转移 (IET) 的动力学.
- 评估了溶液粘度和硫酸盐度对IET率的影响.
- 将实验结果与和人类硫酸盐氧化酶 (SO) 的已知数据进行比较.
主要成果:
- 在SDH中IET被发现是一个第一阶段的过程,独立于溶液粘度和硫酸盐度.
- 这些发现表明,IET直接通过蛋白质介质发生,没有显著的子单元运动.
- SDH的IET机制与动物SO形成鲜明对比,其中IET依赖粘度和硫酸盐,暗示了域间对接.
结论:
- 在Starkeya novella硫酸盐脱酶中,分子内电子转移直接通过蛋白质支架进行.
- 在SDH中观察到的IET机制支持动物硫酸盐氧化酶的域间对接假设.
- IET的粘度和硫酸盐依赖性不是所有硫酸盐氧化酶的固有特性.
相关概念视频
Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
UV–Vis Spectroscopy: Molecular Electronic Transitions
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this process,...
Electrochemical Systems
Electrochemical systems provide a fascinating insight into the dynamic interplay of charged species within various phases. One notable example is the interaction between a membrane permeable to K⁺ ions but not to Cl⁻ ions, separating an aqueous KCl solution from pure water. As K⁺ ions diffuse through the membrane, they generate net charges on each phase, leading to a potential difference between them.Similarly, when a piece of Zn is immersed in an aqueous ZnSO₄ solution, the Zn metal, composed...
The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
Electron Transport Chain Components
The electron transport chain (ETC) is a crucial metabolic pathway that facilitates energy conversion in prokaryotic and eukaryotic cells. In eukaryotes, the ETC comprises four membrane-associated protein complexes in the inner mitochondrial membrane. In prokaryotes, the ETC in the plasma membrane can vary in composition, with fewer or different complexes depending on the organism and environmental conditions. These complexes transfer electrons from electron donors, such as NADH and FADH2, to...
Amino Acid Catabolism
Microorganisms rely on proteins as an essential carbon and energy source, particularly in environments with limited polysaccharides or lipids. However, proteins are too large to cross the plasma membrane unaided, necessitating enzymatic degradation. Microbes secrete extracellular proteases and peptidases that hydrolyze proteins into peptides, which can then be transported across the membrane. Once inside the cell, intracellular proteases degrade these peptides into free amino acids, which...


